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_THE CENTURY SCIENCE SERIES_

EDITED BY SIR HENRY E. ROSCOE, D.C.L., LL.D., F.R.S.


HUMPHRY DAVY

POET AND PHILOSOPHER




The Century Science Series.

EDITED BY

SIR HENRY E. ROSCOE, D.C.L., F.R.S.


  =John Dalton and the Rise of Modern Chemistry.=
     By Sir HENRY E. ROSCOE, F.R.S.


  =Major Rennell, F.R.S., and the Rise of English Geography.=
     By Sir CLEMENTS R. MARKHAM, C. B., F.R.S., President of the Royal
     Geographical Society.


  =Justus von Liebig: his Life and Work (1803-1873).=
     By W. A. SHENSTONE, F.I.C., Lecturer on Chemistry in Clifton
     College.


  =The Herschels and Modern Astronomy.=
     By AGNES M. CLERKE, Author of “A Popular History of Astronomy
     during the 19th Century,” &c.


  =Charles Lyell and Modern Geology.=
     By Rev. Professor T. G. BONNEY, F.R.S.


  =James Clerk Maxwell and Modern Physics.=
     By R. T. GLAZEBROOK, F.R.S., Fellow of Trinity College, Cambridge.


  =Humphry Davy, Poet and Philosopher.=
     By T. E. THORPE, LL.D., F.R.S., Principal Chemist of the Government
     Laboratories.


In Preparation.

  =Michael Faraday: his Life and Work.=
     By Professor SILVANUS P. THOMPSON, F.R.S.


  =Pasteur: his Life and Work.=
     By M. ARMAND RUFFER, M.D., Director of the British Institute of
     Preventive Medicine.


  =Charles Darwin and the Origin of Species.=
     By EDWARD B. POULTON, M.A., F.R.S., Hope Professor of Zoology in
     the University of Oxford.


  =Hermann von Helmholtz.=
     By A. W. RÜCKER, F.R.S., Professor of Physics in the Royal College
     of Science, London.


MACMILLAN & CO., LIMITED, _New York_.




[Illustration: HUMPHRY DAVY.

_ÆTAT 45._

(_From a painting by Jackson_)]




  _THE CENTURY SCIENCE SERIES_


  HUMPHRY DAVY

  POET AND PHILOSOPHER


  BY
  T. E. THORPE, LL.D., F.R.S.


  New York
  MACMILLAN & CO., LIMITED
  1896




PREFACE


For the details of Sir Humphry Davy’s personal history, as set forth
in this little book, I am mainly indebted to the well-known memoirs by
Dr. Paris and Dr. John Davy. As biographies, these works are of very
unequal value. To begin with, Dr. Paris is not unfrequently inaccurate
in his statements as to matters of fact, and disingenuous in his
inferences as to matters of conduct and opinion. The very extravagance
of his laudation suggests a doubt of his judgment or of his sincerity,
and this is strengthened by the too evident relish with which he dwells
upon the foibles and frailties of his subject. The insincerity is
reflected in the literary style of the narrative, which is inflated
and over-wrought. Sir Walter Scott, who knew Davy well and who admired
his genius and his many social gifts, characterised the book as
“_ungentlemanly_” in tone; and there is no doubt that it gave pain to
many of Davy’s friends who, like Scott, believed that justice had not
been done to his character.

Dr. Davy’s book, on the other hand, whilst perhaps too partial at
times--as might be expected from one who writes of a brother to whom he
was under great obligations, and for whom, it is evident, he had the
highest respect and affection--is written with candour, and a sobriety
of tone and a directness and simplicity of statement far more effective
than the stilted euphuistic periods of Dr. Paris, even when he seeks to
be most forcible. When, therefore, I have had to deal with conflicting
or inconsistent statements in the two works on matters of fact, I have
generally preferred to accept the version of Dr. Davy, on the ground
that he had access to sources of information not available to Dr. Paris.

Davy played such a considerable part in the social and intellectual
world of London during the first quarter of the century that, as
might be expected, his name frequently occurs in the personal memoirs
and biographical literature of his time; and a number of journals
and diaries, such as those of Horner, Ticknor, Henry Crabb Robinson,
Lockhart, Maria Edgeworth, and others that might be mentioned, make
reference to him and his work, and indicate what his contemporaries
thought of his character and achievements. Some of these references
will be found in the following pages. It will surprise many Londoners
to know that they owe the Zoological Gardens, in large measure, to a
Professor of Chemistry in Albemarle Street, and that the magnificent
establishment in the Cromwell Road, South Kensington, is the outcome
of the representations, unsuccessful for a time, which he made to his
brother trustees of the British Museum as to the place of natural
history in the national collections. Davy had a leading share also in
the foundation of the Athenæum Club, and was one of its first trustees.

I am further under very special obligations to Dr. Humphry D.
Rolleston, the grand-nephew of Sir Humphry Davy, for much valuable
material, procured through the kind co-operation of Miss Davy, the
granddaughter of Dr. John Davy. This consisted of letters from
Priestley, Kirwan, Southey, Coleridge, Maria Edgeworth, Mrs. Beddoes
(Anna Edgeworth), Sir Joseph Banks, Gregory Watt, and others; and,
what is of especial interest to his biographer, a large number of
Davy’s own letters to his wife. In addition were papers relating to the
invention of the Safety Lamp. Some of the letters have already been
published by Dr. John Davy, but others now appear in print for the
first time. I am also indebted to Dr. Rolleston for the loan of the
portrait representing Davy in Court dress and in the presidential chair
of the Royal Society, which, reproduced in photogravure, forms the
frontispiece to this book. The original is a small highly-finished work
by Jackson, and was painted about 1823. The picture originally belonged
to Lady Davy, who refers to it in the letter to Davies Gilbert (quoted
by Weld in his “History of the Royal Society”), in which she offers
Lawrence’s well-known portrait to the Society, and which, by the way,
the Society nearly lost through the subsequent action of the painter.

For the references to the early history of the Royal Institution I
am mainly indebted to Dr. Bence Jones’s book. I have, moreover, to
thank the Managers of the Institution for their kindness in giving
me permission to see the minutes of the early meetings, and also for
allowing me to consult the manuscripts and laboratory journals in their
possession. These include the original records of Davy’s work, and also
the notes taken by Faraday of his lectures. The Managers have also
allowed me to reproduce Miss Harriet Moore’s sketch--first brought
to my notice by Professor Dewar--of the chemical laboratory of the
Institution as it appeared in the time of Davy and Faraday, and I have
to thank them for the loan of Gillray’s characteristic drawing of the
Lecture Theatre, from which the illustration on p. 70 has been prepared.

I have necessarily had to refer to the relations of Davy to Faraday,
and I trust I have said enough on that subject. Indeed, in my opinion,
more than enough has been said already. It is not necessary to
belittle Davy in order to exalt Faraday; and writers who, like Dr.
Paris, unmindful of George Herbert’s injunction, are prone to adopt an
antithetical style in biographical narrative have, I am convinced, done
Davy’s memory much harm.

I regret that the space at my command has not allowed me to go into
greater detail into the question of George Stephenson’s relations to
the invention of the safety lamp. I have had ample material placed
at my disposal for a discussion of the question, and I am specially
indebted to Mr. John Pattinson and the Council of the Literary and
Philosophical Society of Newcastle-upon-Tyne for their kindness in
lending me a rare, if not unique, collection of pamphlets and reprints
of newspaper articles which made their appearance when the idea of
offering Davy some proof of the value which the coal owners entertained
of his invention was first promulgated. George Stephenson’s claims are
not to be dismissed summarily as pretensions. Indeed, his behaviour
throughout the whole of the controversy increases one’s respect for him
as a man of integrity and rectitude, conscious of what he thought due
to himself, and showing only a proper assurance in his own vindication.
I venture to think, however, that the conclusion to which I have
arrived, and which, from the exigencies of space, is, I fear, somewhat
baldly stated, as to the apportionment of the merit of this memorable
invention, is just and can be well established. Stephenson _might_
possibly have hit upon a safety lamp if he had been allowed to work
out his own ideas independently and by the purely empirical methods
he adopted, and it is conceivable that his lamp _might_ have assumed
its present form without the intervention of Davy; but it is difficult
to imagine that an unlettered man, absolutely without knowledge of
physical science, could have discovered the philosophical principle
upon which the security of the lamp depends.

            T. E. T.
  _May, 1896._




CONTENTS


  CHAPTER                                                           PAGE

     I.--PENZANCE: 1778-1798                                           9

    II.--THE PNEUMATIC INSTITUTION, BRISTOL: 1798-1801                26

   III.--THE PNEUMATIC INSTITUTION, BRISTOL: 1798-1801 (_continued_)  54

    IV.--THE ROYAL INSTITUTION                                        66

     V.--THE CHEMICAL LABORATORY OF THE ROYAL INSTITUTION             90

    VI.--THE ISOLATION OF THE METALS OF THE ALKALIS                  110

   VII.--CHLORINE                                                    134

  VIII.--MARRIAGE--KNIGHTHOOD--“ELEMENTS OF CHEMICAL
           PHILOSOPHY”--NITROGEN TRICHLORIDE--FLUORINE               155

    IX.--DAVY AND FARADAY--IODINE                                    173

     X.--THE SAFETY LAMP                                             192

    XI.--DAVY AND THE ROYAL SOCIETY--HIS LAST DAYS                   213




HUMPHRY DAVY,

POET AND PHILOSOPHER.




CHAPTER I.

PENZANCE: 1778-1798.


Humphry Davy, the eldest son of “Carver” Robert Davy and his wife Grace
Millett, was born on the 17th December, 1778.[A] His biographers are
not wholly agreed as to the exact place of his birth. In the “Lives
of Philosophers of the Time of George III.” Lord Brougham states that
the great chemist was born at Varfell, a homestead or “town-place” in
the parish of Ludgvan, in the Mount’s Bay, where, as the registers and
tombstones of Ludgvan Church attest, the family had been settled for
more than two hundred years.

    [A] In some biographical notices--e.g. in the _Gentleman’s
        Magazine_, xcix. pt. ii. 9--the year is given as 1779.

Mr. Tregellas, in his “Cornish Worthies” (vol. i., p. 247), also leaves
the place uncertain, hesitating, apparently, to decide between Varfell
and Penzance.

According to Dr. John Davy, his brother Humphry was born in Market Jew
Street, Penzance, in a house now pulled down, but which was not far
from the statue of him that stands in front of the Market House of this
town. Dr. Davy further states that Humphry’s parents removed to Varfell
some years after his birth, when he himself was taken charge of by a
Mr. Tonkin.

The Davys originally belonged to Norfolk. The first member of the
family that settled in Cornwall was believed to have acted as steward
to the Duke of Bolton, who in the time of Elizabeth had a considerable
property in the Mount’s Bay. They were, as a class, respectable yeomen
in fairly comfortable circumstances, who for generations back had
received a lettered education. They took to themselves wives from the
Eusticks, Adamses, Milletts, and other old Cornish families, and, if
we may credit the testimony of the tombstones, had many virtues, were
not overgiven to smuggling or wrecking, and, for the most part, died in
their own beds.

The grandfather of Humphry, Edmund Davy, was a builder of repute in the
west of Cornwall, who married well and left his eldest son Robert, the
father of the chemist, in possession of the small copyhold property of
Varfell, to which reference has already been made. Robert, although
a person of some capacity, seems to have been shiftless, thriftless,
and lax in habits. In his youth he had been taught wood-carving, and
specimens of his skill are still to be seen in and about Penzance. But
he practised his art in an irregular fashion, his energies being mainly
spent in field sports, in unsuccessful experiments in farming, and in
hazardous, and for the most part fruitless, ventures in mining. At his
death, which occurred when he was forty-eight, his affairs were found
to be sadly embarrassed; his widow and five children were left in very
straitened circumstances, and Varfell had to be given up.

Fortunately for the children, the mother possessed the qualities
which the father lacked. Casting about for the means of bringing up
and educating her family, she opened a milliner’s shop in the town,
in partnership with a French lady who had fled to England during the
Revolution.

By prudence, good management, and the forbearance of creditors, she not
only succeeded in rearing and educating her children, but gradually
liquidated the whole of her husband’s debts. Some years later, by an
unexpected stroke of fortune, she was able to relinquish her business.
She lived to a good old age, cheerful and serene, happy in the respect
and affection of her children and in the esteem and regard of her
townspeople. Such a woman could not fail to exercise a strong and
lasting influence for good on her children. That it powerfully affected
the character of her son Humphry, he would have been the first to
admit. Nothing in him was more remarkable or more beautiful than his
strong and abiding love for his mother. No matter how immersed he was
in his own affairs, he could always find time amidst the whirl and
excitement of his London life, amidst the worry and anxiety of official
cares--or, when abroad, among the peaks of the Noric Alps or the ruins
of Italian cities--to think of his far-away Cornish home and of her
round whom it was centred. To the last he opened out his heart to her
as he did to none other; she shared in all his aspirations, and lived
with him through his triumphs; and by her death, just a year before his
own, she was happily spared the knowledge of his physical decay and
approaching end.

       *       *       *       *       *

Davy was about sixteen years of age when his father died. At that time
he was a bright, curly-haired, hazel-eyed lad, somewhat narrow-chested
and undergrown, awkward in manner and gait, but keenly fond of
out-door sport, and more distinguished for a love of mischief than of
learning.

Dr. Cardew, of the Truro Grammar School, where, by the kindness of the
Tonkins, he spent the year preceding his father’s death, wrote of him
that he did not at that time discover any extraordinary abilities,
or, so far as could be observed, any propensity to those scientific
pursuits which raised him to such eminence. “His best exercises were
translations from the classics into English verse.” He had previously
spent nine years in the Penzance Grammar School under the tyranny
of the Rev. Mr. Coryton, a man of irregular habits and as deficient
in good method as in scholarship. As Davy used to come up for the
customary castigation, the worthy follower of Orbilius was wont to
repeat--

   “Now, Master Davy,
    Now, sir! I have ’ee
    No one shall save ’ee--
    Good Master Davy!”

He had, too, an unpleasant habit of pulling the boys’ ears, on the
supposition, apparently, that their receptivity for oral instruction
was thereby stimulated. It is recorded that on one occasion Davy
appeared before him with a large plaster on each ear, explaining,
with a very grave face, that he had “put the plasters on to prevent
mortification.” Whence it may be inferred that, in spite of all the
caning and the ear-pulling, there was still much of the unregenerate
Adam left in “good Master Davy.”

Mr. Coryton’s method of inculcating knowledge and the love of learning,
happily, had no permanent ill-effect on the boy. Years afterwards, when
reflecting on his school-life, he wrote, in a letter to his mother--

    “After all, the way in which we are taught Latin and Greek
    does not much influence the important structure of our minds.
    I consider it fortunate that I was left much to myself when a
    child, and put upon no particular plan of study, and that I
    enjoyed much idleness at Mr. Coryton’s school. I perhaps owe to
    these circumstances the little talents that I have and their
    peculiar application.”

If Davy’s abilities were not perceived by his masters, they seemed to
have been fully recognised by his school-fellows--to judge from the
frequency with which they sought his aid in their Latin compositions,
and from the fact that half the love-sick youths of Penzance employed
him to write their valentines and letters. His lively imagination,
strong dramatic power, and retentive memory combined to make him a good
story-teller, and many an evening was spent by his comrades beneath the
balcony of the Star Inn, in Market Jew Street, listening to his tales
of wonder or horror, gathered from the “Arabian Nights” or from his
grandmother Davy, a woman of fervid mind stored with traditions and
ancient legends, from whom he seems to have derived much of his poetic
instinct.

Those who would search in environment for the conditions which
determine mental aptitudes, will find it very difficult to ascertain
what there was in Davy’s boyish life in Penzance to mould him into
a natural philosopher. At school he seems to have acquired nothing
beyond a smattering of elementary mathematics and a certain facility
in turning Latin into English verse. Most of what he obtained in the
way of general knowledge he picked up for himself, from such books as
he found in the library of his benefactor, Mr. John Tonkin. Dr. John
Davy has left us a sketch of the state of society in the Mount’s Bay
during the latter part of the eighteenth century, which serves to show
how unfavourable was the soil for the stimulation and development of
intellectual power. Cornwall at that time had but little commerce; and
beyond the tidings carried by pedlars or ship-masters, or contained
in the _Sherborne Mercury_--the only newspaper which then circulated
in the west of England--it knew little or nothing of what was going
on in the outer world. Its roads were mostly mere bridle-paths, and a
carriage was as little known in Penzance as a camel. There was only one
carpet in the town, the floors of the rooms being, as a rule, sprinkled
with sea-sand:--

    “All classes were very superstitious; even the belief in witches
    maintained its ground, and there was an almost unbounded
    credulity respecting the supernatural and monstrous.... Amongst
    the middle and higher classes there was little taste for
    literature and still less for science, and their pursuits were
    rarely of a dignified or intellectual kind. Hunting, shooting,
    wrestling, cock-fighting, generally ending in drunkenness, were
    what they most delighted in. Smuggling was carried on to a great
    extent, and drunkenness and a low scale of morals were naturally
    associated with it.”

Davy, an ardent, impulsive youth of strong social instincts, fond of
excitement, and not over studious, seems, now that he was released
from the restraint of school-life, to have come under the influence of
such surroundings. For nearly a year he was restless and unsettled,
spending much of his time like his father in rambling about the
country and in fishing and shooting, and passing from desultory study
to occasional dissipation. The death of his father, however, made a
profound impression on his mind, and suddenly changed the whole course
of his conduct. As the eldest son, and approaching manhood, he seems at
once to have realised what was due to his mother and to himself. The
circumstances of the family supplied the stimulus to exertion, and he
dried his mother’s tears with the assurance that he would do all in his
power for his brothers and sisters. A few weeks after the decease of
his father he was apprenticed to Mr. Bingham Borlase, an apothecary and
surgeon practising in Penzance, and at once marked out for himself a
course of study and self-tuition almost unparalleled in the annals of
biography, and to which he adhered with a strength of mind and tenacity
of purpose altogether unlooked for in one of his years and of his gay
and careless disposition. That it was sufficiently ambitious will be
evident from the following transcript from the opening pages of his
earliest note-book--a small quarto, with parchment covers, dated 1795:--

  1. Theology,
    or Religion,              }   { taught by Nature;
      Ethics or Moral virtues }   { by Revelation.

  2. Geography.

  3. My Profession.
    1. Botany.
    2. Pharmacy.
    3. Nosology.
    4. Anatomy.
    5. Surgery.
    6. Chemistry.

  4. Logic.

  5. Languages.
    1. English.
    2. French.
    3. Latin.
    4. Greek.
    5. Italian.
    6. Spanish.
    7. Hebrew.

  6. Physics.
     1. The doctrines and properties of natural bodies.
     2. Of the operations of nature.
     3. Of the doctrines of fluids.
     4. Of the properties of organised matter.
     5. Of the organisation of matter.
     6. Simple astronomy.
     7. Mechanics.
     8. Rhetoric and Oratory.
     9. History and Chronology.
    10. Mathematics.

The note-book opens with “Hints Towards the Investigation of Truth in
Religious and Political Opinions, composed as they occurred, to be
placed in a more regular manner hereafter.” Then follow essays “On the
Immortality and Immateriality of the Soul”; “Body, Organised Matter”;
on “Governments”; on “The Credulity of Mortals”; “An Essay to Prove
that the Thinking Powers depend on the Organisation of the Body”; “A
Defence of Materialism”; “An Essay on the Ultimate End of Being”; “On
Happiness”; “On Moral Obligation.”

These early essays display the workings of an original mind, intent,
it may be, on problems beyond its immature powers, but striving in
all sincerity to work out its own thoughts and to arrive at its own
conclusions. Of course, the daring youth of sixteen who enters upon an
inquiry into the most difficult problems of theology and metaphysics,
with, what he is pleased to call, unprejudiced reason as his sole
guide, quickly passes into a cold fit of materialism. His mind was
too impressionable, however, to have reached the stage of settled
convictions; and in the same note-book we subsequently find the heads
of a train of argument in favour of a rational religious belief founded
on immaterialism.

Metaphysical inquiries seem, indeed, to have occupied the greater
part of his time at this period; and his note-books show that he
made himself acquainted with the writings of Locke, Hartley, Bishop
Berkeley, Hume, Helvetius, Condorcet, and Reid, and that he had some
knowledge of the doctrines of Kant and the Transcendentalists.

That he thought for himself, and was not unduly swayed by authority,
is evident from the general tenour of his notes, and from the critical
remarks and comments by which they are accompanied. Some of these are
worth quoting:--

    “Science or knowledge is the association of a number of ideas,
    with some idea or term capable of recalling them to the mind in a
    certain order.”

    “By examining the phenomena of Nature, a certain similarity of
    effects is discovered. The business of science is to discover
    these effects, and to refer them to some common cause; that is to
    generalise ideas.”

As his impulsive, ingenuous disposition led him, even to the last, to
speak freely of what was uppermost in his mind at the moment, we may be
sure that his elders, the Rev. Dr. Tonkin, his good friend John Tonkin,
and his grandmother Davy, with whom he was a great favourite, as he was
with most old people, must have been considerably exercised at times
with the metaphysical disquisitions to which they were treated; and we
can well imagine that their patience was occasionally as greatly tried
as that of the worthy member of the Society of Friends who wound up an
argument with the remark, “I tell thee what, Humphry, thou art the most
quibbling hand at a dispute I ever met with in my life.” Whether it was
in revenge for this sally that the young disputant composed the “Letter
on the Pretended Inspiration of the Quakers” which is to be found in
one of his early note-books, does not appear.

We easily trace in these early essays the evidences of that facility
and charm of expression which a few years later astonished and
delighted his audiences at the Royal Institution, and which remained
the characteristic features of his literary style. These qualities were
in no small degree strengthened by his frequent exercises in poetry.
For Davy had early tasted of the Pierian spring, and, like Pope, may
be said to have lisped in numbers. At five he was an _improvisatore_,
reciting his rhymes at some Christmas gambols, attired in a fanciful
dress prepared by a playful girl who was related to him. That he
had the divine gift was acknowledged by no less an authority than
Coleridge, who said that “if Davy had not been the first Chemist, he
would have been the first Poet of his age.” Southey also, who knew
him well, said after his death, “Davy was a most extraordinary man;
he would have excelled in any department of art or science to which
he had directed the powers of his mind. He had all the elements of a
poet; he only wanted the art. I have read some beautiful verses of his.
When I went to Portugal, I left Davy to revise and publish my poem of
‘Thalaba.’”

Throughout his life he was wont, when deeply moved, to express his
feelings in verse; and at times even his prose was so suffused with the
glow of poetry that to some it seemed altiloquent and inflated. Some of
his first efforts appeared in the “Annual Anthology,” a work printed
in Bristol in 1799, and edited by Southey and Tobin, and interesting
to the book-hunter as one of the first of the literary “Annuals” which
subsequently became so fashionable.

Davy had an intense love of Nature, and nothing stirred the poetic fire
within him more than the sight of some sublime natural object such as
a storm-beaten cliff, a mighty mountain, a resistless torrent, or some
spectacle which recalled the power and majesty of the sea. Not that he
was insensible to the simpler charms of pastoral beauty, or incapable
of sympathy with Nature in her softest, tenderest moods. But these
things never seemed to move him as did some scene of grandeur, or some
manifestation of stupendous natural energy.

The following lines, written on Fair Head during the summer of 1806,
may serve as an example of how scenery when associated in his mind with
the sentiments of dignity or strength affected him:--

   “Majestic Cliff! Thou birth of unknown time,
    Long had the billows beat thee, long the waves
    Rush’d o’er thy hollow’d rocks, ere life adorn’d
    Thy broken surface, ere the yellow moss
    Had tinted thee, or the wild dews of heaven
    Clothed thee with verdure, or the eagles made
    Thy caves their aëry. So in after time
    Long shalt thou rest unalter’d mid the wreck
    Of all the mightiness of human works;
    For not the lightning, nor the whirlwind’s force,
    Nor all the waves of ocean, shall prevail
    Against thy giant strength, and thou shalt stand
    Till the Almighty voice which bade thee rise
    Shall bid thee fall.”

In spite of a love-passage which seems to have provoked a succession
of sonnets, his devotions to Calliope were by no means so unremitting
as to prevent him from following the plan of study he had marked out
for himself. His note-books show that in the early part of 1796 he
attacked the mathematics, and with such ardour that in little more than
a year he had worked through a course of what he called “Mathematical
Rudiments,” in which he included “fractions, vulgar and decimal;
extraction of roots; algebra (as far as quadratic equations); Euclid’s
elements of geometry; trigonometry; logarithms; sines and tangents;
tables; application of algebra to geometry, etc.”

In 1797 he began the study of natural philosophy, and towards the
end of this year, when he was close on nineteen, he turned his
attention to chemistry, merely, however, at the outset as a branch of
his professional education, and with no other idea than to acquaint
himself with its general principles. His good fortune led him to select
Lavoisier’s “Elements”--probably Kerr’s translation, published in
1796--as his text-book. No choice could have been happier. The book
is well suited to a mind like Davy’s, and he could not fail to be
impressed by the boldness and comprehensiveness of its theory, its
admirable logic, and the clearness and precision of its statements.

From reading and speculation he soon passed to experiment. But at
this time he had never seen a chemical operation performed, and had
little or no acquaintance with even as much as the forms of chemical
apparatus. Phials, wine-glasses, tea-cups, and tobacco-pipes, with
an occasional earthen crucible, were all the paraphernalia he could
command; the common mineral acids, the alkalis, and a few drugs from
the surgery constituted his stock of chemicals. Of the nature of these
early trials we know little. It is, however, almost certain that the
experiments with sea-weed, described in his two essays “On Heat, Light
and the Combinations of Light” and “On the Generation of Phosoxygen
and the Causes of the Colours of Organic Beings” (see p. 30), were
made at this time, and it is highly probable that the experiments on
land-plants, which are directly related to those on the _Fuci_ and
are described in connection with them, were made at the same period.
That he pursued his experiments with characteristic ardour is borne
out by the testimony of members of his family, particularly by that of
his sister, who sometimes acted as his assistant, and whose dress too
frequently suffered from the corrosive action of his chemicals. The
good Mr. Tonkin and his worthy brother, the Reverend Doctor, were also
from time to time abruptly and unexpectedly made aware of his zeal.
“This boy Humphry is incorrigible! He will blow us all into the air!”
were occasional exclamations heard to follow the alarming noises which
now and then proceeded from the laboratory. The well-known anecdote
of the syringe which had formed part of a case of instruments of a
shipwrecked French surgeon, and which Davy had ingeniously converted
into an air-pump, although related by Dr. Paris “with a minuteness and
vivacity worthy of Defoe,” is, in all probability, apocryphal. Nor has
Lord Brougham’s story, that his devotion to chemical experiments and
“his dislike to the shop” resulted in a disagreement with his master,
and that “he went to another in the same place,” where “he continued in
the same course,” any surer foundation in fact.

Two or three circumstances conduced to develop Davy’s taste for
scientific pursuits, and to extend his opportunities for observation
and experiment. One was his acquaintance with Mr. Gregory Watt; another
was his introduction to Mr. Davies Gilbert (then Mr. Davies Giddy), a
Cornish gentleman of wealth and position, who lived to succeed him in
the presidential chair of the Royal Society.

Gregory Watt, the son of James Watt, the engineer, by his second
marriage, was a young man of singular promise who, had he lived,
would--if we may judge from his paper in the _Philosophical
Transactions_--have almost certainly acquired a distinguished position
in science. Of a weakly, consumptive habit, he was ordered to spend the
winter of 1797 in Penzance, where he lodged with Mrs. Davy, boarding
with the family. Young Watt was about two years older than Davy, and
had just left the University of Glasgow, “his mind enriched beyond
his age with science and literature, with a spirit above the little
vanities and distinctions of the world, devoted to the acquisition of
knowledge.” He remained in Penzance until the following spring, and by
his example, and by the generous friendship which he extended towards
him, he developed and strengthened Davy’s resolve to devote himself
to science. Davy’s introduction to Mr. Gilbert, “a man older than
himself, with considerable knowledge of science generally, and with
the advantages of a University education,” was also a most timely and
propitious circumstance. According to Dr. Paris--

    “Mr. Gilbert’s attention was attracted to the future philosopher,
    as he was carelessly swinging over the hatch, or half-gate, of
    Mr. Borlase’s house, by the humorous contortions into which
    he threw his features. Davy it may be remarked, when a boy,
    possessed a countenance which even in its natural state was very
    far from comely; while his round shoulders, inharmonious voice
    and insignificant manner, were calculated to produce anything
    rather than a favourable impression: in riper years, he was what
    might be called ‘good-looking,’ although as a wit of the day
    observed, his aspect was certainly of the ‘bucolic’ character.
    The change which his person underwent, after his promotion to the
    Royal Institution, was so rapid that in the days of Herodotus, it
    would have been attributed to nothing less than the miraculous
    interposition of the Priestesses of Helen. A person, who happened
    to be walking with Mr. Gilbert upon the occasion alluded to,
    observed that the extraordinary looking boy in question was young
    Davy, the carver’s son, who, he added, was said to be fond of
    making chemical experiments.”

Mr. Gilbert was thus led to interest himself in the boy, whom he
invited to his house at Tredrea, offering him the use of his library,
and such other assistance in his studies as he could render. On one
occasion he was taken over to the Hayle Copper-House, and had the
opportunity of seeing a well-appointed laboratory:

    “The tumultuous delight which Davy expressed on seeing, for the
    first time, a quantity of chemical apparatus, hitherto only
    known to him through the medium of engravings, is described
    by Mr. Gilbert as surpassing all description. The air-pump
    more especially fixed his attention, and he worked its piston,
    exhausted the receiver, and opened its valves, with the
    simplicity and joy of a child engaged in the examination of a new
    and favourite toy.”

It has already been stated that in the outset Davy attacked science as
he did metaphysics, approaching it from the purely theoretical side.
As might be surmised, his love of speculation quickly found exercise
for itself, and within four months of his introduction to the study of
science he had conceived and elaborated a new hypothesis on the nature
of heat and light, which he communicated to Dr. Beddoes.

Dr. Thomas Beddoes was by training a medical man, who in various ways
had striven to make a name for himself in science. He is known to the
chemical bibliographer as the translator of the Chemical Essays of
Scheele, and at one time occupied the Chair of Chemistry at Oxford. The
geological world at the end of the eighteenth century regarded him as a
zealous and uncompromising Plutonist. His character was thus described
by Davy, who in the last year of his life jotted down, in the form of
brief notes, his reminiscences of some of the more remarkable men of
his acquaintance:--

    “Beddoes was reserved in manner and almost dry; but his
    countenance was very agreeable. _He was cold_ in conversation,
    and apparently much occupied with his own peculiar views and
    theories. Nothing could be a stronger contrast to his apparent
    coldness in discussion than his wild and active imagination,
    which was as poetical as Darwin’s.... On his deathbed he wrote me
    a most affecting letter, regretting his scientific aberrations.”

One of Dr. Beddoes’s “scientific aberrations” was the inception and
establishment of the Pneumatic Institution, which he founded with a
view of studying the medicinal effects of the different gases, in the
sanguine hope that powerful remedies might be found amongst them. The
Institution, which was supported wholly by subscription, was to be
provided with all the means likely to promote its objects--a hospital
for patients, a laboratory for experimental research, and a theatre for
lecturing.

In seeking for a person to take charge of the laboratory, Dr. Beddoes
bethought him of Davy, who had been recommended to him by Mr. Gilbert.
In a letter dated July 4th, 1798, Dr. Beddoes thus writes to Mr.
Gilbert:--

    “I am glad that Mr. Davy has impressed you as he has me. I have
    long wished to write to you about him, for I think I can open
    a more fruitful field of investigation than any body else. Is
    it not also his most direct road to fortune? Should he not
    bring out a favourable result he may still exhibit talents for
    investigation, and entitle himself to public confidence more
    effectually than by any other mode. He must be maintained, but
    the fund will not furnish a salary from which a man can lay up
    anything. He must also devote his time for two or three years to
    the investigation. I wish you would converse with him upon the
    subject.... I am sorry I cannot at this moment specify a yearly
    sum, nor can I say with certainty whether all the subscribers
    will accede to my plan; most of them will, I doubt not. I have
    written to the principal ones, and will lose no time in sounding
    them all.”

A fortnight later, Dr. Beddoes again wrote to Mr. Gilbert:--

    “I have received a letter from Mr. Davy since I wrote to you. He
    has oftener than once mentioned a _genteel maintenance_, as a
    preliminary to his being employed to superintend the Pneumatic
    Hospital. I fear the funds will not allow an ample salary;
    he must however be maintained. I can attach no idea to the
    epithet _genteel_, but perhaps all difficulties would vanish in
    conversation; at least I think your conversing with Mr. Davy
    will be a more likely way of smoothing difficulties than our
    correspondence. It appears to me, that this appointment will
    bear to be considered as a part of Mr. Davy’s medical education,
    and that it will be a great saving of expense to him. It may
    also be the foundation of a lucrative reputation; and certainly
    nothing on my part shall be wanting to secure to him the credit
    he may deserve. He does not undertake to discover cures for
    this or that disease; he may acquire just applause by bringing
    out clear, though negative results. During my journeys into the
    country I have picked up a variety of important and curious
    facts from different practitioners. This has suggested to me the
    idea of collecting and publishing such facts as this part of
    the country will from time to time afford. If I could procure
    chemical experiments that bore any relation to organised nature,
    I would insert them. If Mr. Davy does not dislike this method
    of publishing his experiments I would gladly place them at the
    head of my first volume, but I wish not that he should make any
    sacrifice of judgment or inclination.”

Thanks to Mr. Gilbert, the negotiation was brought to a successful
issue. Mrs. Davy yielded to her son’s wishes, and Mr. Borlase
surrendered his indenture, on the back of which he wrote that he
released him from “all engagements whatever on account of his excellent
behaviour”; adding, “because being a youth of great promise, I would
not obstruct his present pursuits, which are likely to promote his
fortune and his fame.” The only one of his friends who disapproved of
the scheme was his old benefactor, Mr. John Tonkin, who had hoped to
have established Davy in his native town as a surgeon. Mr. Tonkin was
so irritated at the failure of his plans that he altered his will, and
revoked the legacy of his house, which he had bequeathed to him.




CHAPTER II.

THE PNEUMATIC INSTITUTION, BRISTOL, 1798-1801.


On October 2nd, 1798, Davy set out for Clifton with such books and
apparatus as he possessed, and the MSS. of his essays on Heat and Light
safely stowed away among his baggage. He was in the highest spirits,
and full of confidence in the future. On his way through Okehampton he
met the London coach decked with laurels and ribbons, and bringing the
news of Nelson’s victory of the Nile, which he interpreted as a happy
omen. A few days after his arrival, he thus wrote to his mother:--

            “_October 11th, 1798._ Clifton.

    “MY DEAR MOTHER,--I have now a little leisure time, and I am
    about to employ it in the pleasing occupation of communicating to
    you an account of all the _new_ and _wonderful_ events that have
    happened to me since my departure.

    “I suppose you received my letter, written in a great hurry last
    Sunday, informing you of my safe arrival and kind reception. I
    must now give you a more particular account of Clifton, the place
    of my residence, and of my new friends Dr. and Mrs. Beddoes and
    their family.

    “Clifton is situated on the top of a hill, commanding a view
    of Bristol and its neighbourhood, conveniently elevated above
    the dirt and noise of the city. Here are houses, rocks, woods,
    town and country in one small spot; and beneath us, the
    sweetly-flowing Avon, so celebrated by the poets. Indeed there
    can hardly be a more beautiful spot; it almost rivals Penzance
    and the beauties of Mount’s Bay.

    “Our house is capacious and handsome; my rooms are very large,
    nice and convenient; and, above all, I have an excellent
    laboratory. Now for the inhabitants, and, first, Dr. Beddoes,
    who, between you and me, is one of the most original men I ever
    saw--uncommonly short and fat, with little elegance of manners,
    and nothing characteristic _externally_ of genius or science;
    extremely silent, and in a few words, a very bad companion. His
    behaviour to me, however, has been particularly handsome. He has
    paid me the highest compliments on my discoveries, and has, in
    fact, become a convert to my theory, which I little expected. He
    has given up to me the whole of the business of the Pneumatic
    Hospital, and has sent to the editor of the _Monthly Magazine_ a
    letter, to be published in November, in which I have the honour
    to be mentioned in the highest terms. Mrs. Beddoes is the reverse
    of Dr. Beddoes--extremely cheerful, gay and witty; she is one of
    the most pleasing women I have ever met with. With a cultivated
    understanding and an excellent heart, she combines an uncommon
    simplicity of manners. We are already very great friends. She
    has taken me to see all the fine scenery about Clifton; for the
    Doctor, from his occupations and his bulk, is unable to walk
    much. In the house are two sons and a daughter of Mr. Lambton,
    very fine children, from five to thirteen years of age.

    “I have visited Mr. Hare, one of the principal subscribers to
    the Pneumatic Hospital, who treated me with great politeness.
    I am now very much engaged in considering of the erection of
    the Pneumatic Hospital, and the mode of conducting it. I shall
    go down to Birmingham to see Mr. Watt and Mr. Keir in about a
    fortnight, where I shall probably remain a week or ten days;
    but before then you will again hear from me. We are just going
    to print at Cottle’s; in Bristol, so that my time will be much
    taken up the ensuing fortnight in preparations for the press. The
    theatre for lecturing is not yet open; but, if I can get a large
    room in Bristol, and subscribers, I intend to give a course of
    chemical lectures, as Dr. Beddoes seems much to wish it.

    “My journey up was uncommonly pleasant; I had the good fortune
    to travel all the way with acquaintances. I came into Exeter in
    a most joyful time, the celebration of Nelson’s victory. The
    town was beautifully illuminated, and the inhabitants loyal and
    happy....

    “It will give you pleasure when I inform you that all my
    expectations are answered and that my situation is just what I
    could wish. But, for all this, I very often think of Penzance and
    my friends, with a wish to be there; however that time will come.
    We are some time before we become accustomed to new modes of
    living and new acquaintances.

            “Believe me, your affectionate son,
                                  “HUMPHRY DAVY.”

Mrs. Beddoes, of whom Davy speaks in such appreciative terms, was one
of the many sisters of Maria Edgeworth. She seems to have possessed
much of the intelligence, wit, vivacity, and sunny humour of the
accomplished authoress of “Castle Rackrent”; and, by her charm of
manner and her many social gifts, to have made her husband’s house the
centre of the literary and intellectual life of Clifton. Thanks to her
influence, Davy had the good fortune to be brought into contact, at
the very outset of his career, with Southey, Coleridge, the Tobins,
Miss Edgeworth, and other notable literary men and women of his time,
with many of whom he established firm and enduring friendships. He had
always a sincere admiration for his fair patroness, and a grateful
memory of her many acts of kindness to him at this period of his life.
That she in turn had an esteem amounting to affection for the gifted
youth is evident from the language of tender feeling and warm regard in
which her letters to him are expressed. The sonnets accompanying these
letters are couched in terms which admit of no doubt of the strength of
her sentiments of sympathy and admiration, and some of the best efforts
of his muse were addressed to her in return.

His work and prospects at the Pneumatic Institution are sufficiently
indicated in the following letter to his friend and patron, Mr. Davies
Gilbert, written five weeks after his arrival at Clifton:--

            “Clifton, _November 12, 1798_.

    “DEAR SIR,--I have purposely delayed writing until I could
    communicate to you some intelligence of importance concerning the
    Pneumatic Institution. The speedy execution of the plan will, I
    think, interest you both as a subscriber and a friend to science
    and mankind. The present subscription is, we suppose nearly
    adequate to the purpose of investigating the medicinal powers of
    factitious airs; it still continues to increase, and we may hope
    for the ability of pursuing the investigation to its full extent.
    We are negotiating for a house in Dowrie Square, the proximity
    of which to Bristol, and its general situation and advantages,
    render it very suitable to the purpose. The funds will, I
    suppose, enable us to provide for eight or ten patients in the
    hospital, and for as many out of it as we can procure.

    “We shall try the gases in every possible way. They may be
    condensed by pressure and rarefied by heat. _Quere_,--Would not
    a powerful injecting syringe furnished with two valves, one
    opening into an air-holder and the other into the breathing
    chamber, answer the purpose of compression better than any
    other apparatus? Can you not, from your extensive stores of
    philosophy, furnish us with some hints on this subject? May
    not the non-respirable gases furnish a class of different
    stimuli? of which the oxymuriatic acid gas [chlorine] would
    stand the highest, if we may judge from its effects on the
    lungs; then, probably, _gaseous oxyd of azote_ [nitrous oxide?]
    and _hydrocarbonate_ [the gases obtained by passing steam over
    red-hot charcoal].

    “I suppose you have not heard of the discovery of the native
    _sulphate of strontian_ in England. I shall perhaps surprise
    you by stating that we have it in large quantities here. It had
    long been mistaken for _sulphate of barytes_, till our friend
    Clayfield, on endeavouring to procure the _muriate of barytes_
    from it by decomposition, detected the strontian. We opened a
    fine vein of it about a fortnight ago at the Old Passage near the
    mouth of the Severn.[B]...

    “We are printing in Bristol the first volume of the ‘West
    Country Collection,’ which will, I suppose, be out in the
    beginning of January.

    “Mrs. Beddoes ... is as good, amiable, and elegant as when you
    saw her.

    “Believe me, dear Sir, with affection and respect, truly yours,

            “HUMPHRY DAVY.”

    [B] _Cf._ An account of several veins of Sulphate of
        Strontites, found in the neighbourhood of Bristol, with
        an Analysis of the different varieties. By W. Clayfield.
        “Nicholson’s Journ.,” III., 1800, pp. 36-41.

The work alluded to in this letter made its appearance in the early
part of 1799, under the title of “Contributions to Physical and Medical
Knowledge, principally from the West of England; collected by Thomas
Beddoes, M.D.” The first half of the volume, in accordance with the
editor’s promise, is occupied by two essays from Davy: the first “On
Heat, Light, and the Combinations of Light, with a new Theory of
Respiration”; the second “On the Generation of Phosoxygen (Oxygen Gas),
and on the Causes of the Colours of Organic Beings.”

To the student these essays have no other interest than is due to
the fact that they are Davy’s first contribution to the literature
of science. No beginning could be more inauspicious. It is the first
step that costs, and Davy’s first step had well nigh cost him all that
he lived for. As additions to knowledge they are worthless; indeed,
a stern critic might with justice characterise them in much stronger
language. Nowadays such writings would hopelessly damn the reputation
of any young aspirant for scientific fame, for it is indeed difficult
to believe, as we read paragraph after paragraph, that their author had
any real conception of science, or that he was capable of understanding
the need or appreciating the value of scientific evidence.

The essays are partly experimental, partly speculative, and the
author apparently would have us believe that the speculations are
entirely subservient to and dependent on the experiments. Precisely
the opposite is the case. Davy’s work had its origin in Lavoisier’s
“Traité Elémentaire,” almost the only text-book of chemistry he
possessed. Lavoisier taught, in conformity with the doctrine of
his time, that heat was a material substance, and that oxygen
was essentially a compound body, composed of a simple substance
associated with the matter of heat, or caloric. The young novitiate
puts on his metaphysical shield and buckler; and with the same jaunty
self-confidence that he assailed Locke and criticised Berkeley, enters
the lists against this doctrine, determined, as he told Gregory Watt,
“to demolish the French theory in half an hour.”

After a few high-sounding but somewhat disconnected introductory
sentences, and a complimentary allusion to “the theories of a
celebrated medical philosopher, Dr. Beddoes,” he proceeds to put
Lavoisier’s question, “La lumière, est-elle une modification du
calorique, ou bien le calorique est-il une modification de la lumière?”
to the test of experiment. This he does by repeating Hawksbee’s old
experiment of snapping a gunlock “armed with an excellent flint” in an
exhausted receiver. The experiment fails in his hands; such phenomena
as he observes he misinterprets, and he at once concludes that light
and heat have nothing essentially in common. “Nor can light be as some
philosophers suppose, a vibration of the imaginary fluid ether. For
even granting the existence of this fluid it must be present in the
exhausted receiver as well as in atmospheric air; and if light is a
vibration of this fluid, generated by collision between flint and steel
in atmospheric air, it should likewise be produced in the exhausted
receiver, where a greater quantity of ether is present, which is not
the case.” Since, then, it is neither an effect of caloric nor of an
ethereal fluid, and “as the impulse of a material body on the organ
of vision is essential to the generation of a sensation, _light is
consequently matter of a peculiar kind_, capable when moving through
space with the greatest velocity, of becoming the source of a numerous
class of our sensations.”

By experiments, faultless in principle but wholly imperfect in
execution, he next seeks to show that caloric, or the matter of heat,
has no existence. His reasoning is clear, and his conceptions have
the merit of ingenuity, but any real acquaintance with the conditions
under which the experiments were made would have convinced him that
the results were untrustworthy and equivocal; and yet, in spite of
the dubious character of his observations, he arrived at a theory
of the essential nature of heat which is in accord with our present
convictions, and which he states in the following terms:--

    “Heat, or that power which prevents the actual contact of the
    corpuscles of bodies, and which is the cause of our peculiar
    sensations of heat and cold, may be defined a peculiar motion,
    probably a vibration, of the corpuscles of bodies, tending to
    separate them.”

This conception of the nature of heat did not, of course, originate
with him, and it was a question with his contemporaries how far he was
influenced by Rumford’s work and teaching. On this point Dr. Beddoes’s
testimony is direct and emphatic. He says:--

    “The author [Davy] derived no assistance whatever from the
    Count’s ingenious labours. My first knowledge of him arose from
    a letter written in April 1798, containing an account of his
    researches on heat and light; and his first knowledge of Count
    Rumford’s paper was conveyed by my answer. The two Essays contain
    proofs enough of an original mind to make it credible that
    the simple and decisive experiments on heat were independently
    conceived. Nor is it necessary, in excuse or in praise of his
    system, to add, that, at the time it was formed, the author was
    under twenty years of age, pupil to a surgeon-apothecary, in the
    most remote town of Cornwall, with little access to philosophical
    books, and none at all to philosophical men.”

Having thus, with Beddoes, expunged caloric from his chemical system,
Davy proceeds to elevate the matter of light into its place. According
to Lavoisier oxygen gas was a compound of a simple substance and
caloric; Davy seeks to show that it is a compound of a simple substance
and light. He objects to the use of the word “gas,” since, according to
French doctrine, it is to be taken as implying not merely a state of
aggregation but a combination of caloric with another substance, and
suggests therefore that what was called oxygen gas should henceforth be
known as _phosoxygen_. His “proofs” that oxygen is really a compound of
a simple substance with “matter in a peculiar state of existence” are
perhaps the most futile that could be imagined. Charcoal, phosphorus,
sulphur, hydrogen, and zinc were caused to burn in oxygen; _light_ was
evolved, oxides were formed, _and a deficiency of weight was in each
case observed_. He regrets, however, that he “possessed no balance
sufficiently accurate to determine exactly the deficiency of weight
from the light liberated in different combustive processes.”

    “From these experiments, it appears that in the chemical process
    of the formation of many oxyds and acids, light is liberated,
    the phosoxygen and combustible base consumed, and a new body
    formed.... Since light is liberated in these processes, it is
    evident that it must be liberated either from the phosoxygen
    or from the combustible body.... If the light liberated in
    combustion be supposed (according to Macquer’s and Hutton’s
    theories) to arise from the combustible body, then phosoxygen
    must be considered as a simple substance; and it follows on this
    supposition, that whenever phosoxygen combines with combustible
    bodies, either directly or by attraction from any of its
    combinations, light must be liberated, which is not the case, as
    carbon, iron and many other substances, may be oxydated by the
    decomposition of water without the liberation of light.”

Davy is here on the horns of a dilemma, but he ignores the difficulty,
and, with characteristic “flexibility of adaptation,” proceeds to offer
synthetical proofs “that the presence of light is absolutely essential
to the production of phosoxygen.” The character of the “proofs” is
sufficiently indicated by the following extracts:--

    “When pure oxyd of lead is heated as much as possible, included
    from light, it remains unaltered; but when exposed to the light
    of a burning-glass, or even of a candle, phosoxygen is generated
    and the metal revivified.”

    “Oxygenated muriatic acid [chlorine] is a compound of muriatic
    acid, oxygen and light, as will be hereafter proved. The combined
    light is not sufficient to attract the oxygen from the base
    [muriatic acid] to form phosoxygen; but its attraction for oxygen
    renders the [oxygenated muriatic] acid decomposable. If this acid
    be heated in a close vessel and light excluded no phosoxygen is
    formed; but if it be exposed to the solar light, phosoxygen is
    formed; the acid loses its oxygen and light and becomes muriatic
    acid.”

    “A plant of Arenaria Tenuifolia planted in a pot filled with
    very dry earth, was inserted in carbonic acid, under mercury.
    The apparatus was exposed to the solar light, for four days
    successively, in the month of July. By this time the mercury had
    ascended considerably. The gas in the vessel was now measured.
    There was a deficiency of one-sixth of the whole quantity. After
    the carbonic acid was taken up by potash, the remaining quantity,
    equal to one-seventh of the whole, was _phosoxygen almost pure_.
    From this experiment, it is evident that carbonic acid is
    decomposed by two attractions; that of the vegetable for carbon
    and of light for oxygen: the carbon combines with the plant,
    and the light and oxygen combined are liberated in the form of
    phosoxygen.”

The accounts which Davy gives of his experiments, as well as of the
phenomena which he professes to have observed, may awaken an uneasy
doubt as to his absolute integrity; for, it is hardly necessary to
point out, he could not possibly have obtained the results which he
describes. The presence or absence of light in no wise affects the
decomposition by heat of minium; chlorine, as he himself subsequently
established, contains no oxygen; and a plant is incapable of
decomposing pure undiluted carbonic acid, even in the brightest
sunshine. But the work of a youth of nineteen, imaginative, sanguine,
and impetuous, with no training as an experimentalist, and with only
a limited access to scientific memoirs, cannot be judged by too
severe a canon. The faculty of self-deception, even in the largest
and most receptive minds, often in those of matured power and ripened
experience, is boundless. Davy himself affords an exemplification of
the truth of his own words, written years afterwards: “The human mind
is always governed not by what it knows, but by what it believes; not
by what it is capable of attaining, but by what it desires.”

It is not necessary to show how the presumptuous youth drove his hobby
with all the reckless daring of a Phæton. Phlogiston and oxygen had in
turn been the central conceptions of theories of chemistry; phosoxygen
was to supplant them. It was to explain everything--the blue colour
of the sky, the electric fluid, the Aurora Borealis, the phenomena of
fiery meteors, the green of the leaf, the red of the rose, and the
sable hue of the Ethiopian; perception, thought, and happiness; and why
women are fairer than men. But Jupiter, in the shape of a Reviewer,
soon hurled the adventurous boy from the giddy heights to which he had
soared. The “West Country Collection” received scant sympathy from the
critics, and the phosoxygen theory was either mercilessly ridiculed, or
treated with contempt.

There is no doubt that Davy keenly felt the position in which he now
stood. His pride was humbled, and the humiliation was as gall and
wormwood. The vision of fame which his ardour had conjured up on the
top of the Bristol coach--was it all a baseless fabric, and its train
of honours and emoluments an insubstantial pageant? All he could plead
was that his critics had not understood that these experiments were
made when he had studied chemistry only four months, when he had never
seen a single experiment executed, and when all his information was
derived from Nicholson’s “Chemistry” and Lavoisier’s “Elements.” But
his good sense quickly came to his rescue. After the first feelings of
anger and mortification had passed, he recognised the justice of his
punishment, much as he might resent the mode in which it was inflicted.
How keen was the smart will appear from the following reflection,
written in the August of the year in which the essays were published:--

    “When I consider the variety of theories that may be formed
    on the slender foundation of one or two facts, I am convinced
    that it is the business of the true philosopher to avoid them
    altogether. It is more laborious to accumulate facts than to
    reason concerning them; but one good experiment is of more value
    than the ingenuity of a brain like Newton’s.”

About the same time he wrote:--

    “I was perhaps wrong in publishing, with such haste, a new theory
    of chemistry. My mind was ardent and enthusiastic. I believed
    that I had discovered the truth. Since that time my knowledge of
    facts is increased--since that time I have become more sceptical.”

In the October of the same year he wrote:--

    “Convinced as I am that chemical science is in its infancy, that
    an infinite variety of new facts must be accumulated before our
    powers of reasoning will be sufficiently extensive, I renounce my
    own particular theory as being a complete arrangement of facts:
    it appears to me now only as the most _probable_ arrangement.”

By the end of the year the repentance was complete, and recantation
followed. In a letter which appeared in Nicholson’s Journal in
February, 1800, he corrects some of the errors into which he had
fallen, and says, “I beg to be considered as a sceptic with regard to
my own particular theory of the combinations of light, and theories of
light in general.” To the end of his days Davy never forgot the lesson
which his earliest effort had taught him; and there is no question that
the memory of it acted as a salutary check on the exuberance of his
fancy and the flight of his imagination. The wound to his self-love
was, however, never wholly healed. Nothing annoyed him more than any
reference to Beddoes’s book, and he declared to Dr. Hope that he would
joyfully relinquish any little glory or reputation he might have
acquired by his later researches were it possible to withdraw his share
in that work and to remove the impression he feared it was likely to
produce.

And yet, in spite of the unqualified censure with which they were
received, and of the severe condemnation of them by their own author,
we are disposed to agree with Dr. Davy that posterity will not suffer
these essays to be wholly blotted out from the records of science. That
the experimental part was for the most part radically bad, that the
generalisation was hasty and presumptuous, and the reasoning imperfect,
cannot be gainsaid. But, withal, the essays display some of Davy’s
best and happiest characteristics. There is dignity of treatment and a
sense of the nobility of the theme on which he is engaged; the literary
quality is admirable; there is clearness of perception and perspicuity
of statement; the facts as he knew them--or as he thought he knew
them--are marshalled with ingenuity and with a logical precision
worthy of his model and teacher Lavoisier; his style is sonorous and
copious, even to redundancy--some of the periods indeed glow with all
the fervour and richness of his Royal Institution lectures. However
wild and visionary his speculations may seem, minds like those of
Coleridge and Southey were not insensible to the intrinsic beauty of
some of his ideas. His theory of respiration might not be true, but
it had at least the merit of poetic charm in its consequence that the
power and perspicacity of a thinker had some relation to the amount of
light secreted by his brain. Even good old Dr. Priestley, whose Pegasus
could never be stirred beyond the gentlest of ambles, tells us in the
Appendix to his “Doctrine of Phlogiston Established” that Mr. H. Davy’s
essays had impressed him with a high opinion of the philosophical
acumen of their author. “His ideas were to me new and very striking;
but,” he adds, with a caution that was not habitual, “they are of too
great consequence to be decided upon hastily.”

Among the letters entrusted to me is one from Priestley, which must
have been particularly gratifying to the young man. It is as follows:--

            “Northumberland, _Oct. 31, 1801_.

    “SIR,--I have read with admiration your excellent publications,
    and have received much instruction from them. It gives me
    peculiar satisfaction that, as I am far advanced in life,
    and cannot expect to do much more, I shall leave so able a
    fellow-labourer of my own country in the great fields of
    experimental philosophy. As old an experimenter as I am, I was
    near forty before I made any experiments on the subject of
    Air, and then without, in a manner, any previous knowledge of
    chemistry. This I picked up as I could, and as I found occasion
    for it, from books. I was also without apparatus, and laboured
    under many other disadvantages. But my unexpected success induced
    the friends of science to assist me, and then I wanted for
    nothing. I rejoice that you are so young a man; and perceiving
    the ardour with which you begin your career, I have no doubt of
    your success.

    “My son, for whom you express a friendship, and which he warmly
    returns, encourages me to think that it may not be disagreeable
    to you to give me information occasionally of what is passing in
    the philosophical world, now that I am at so great a distance
    from it, and interested, as you may suppose, in what passes in
    it. Indeed, I shall take it as a great favour. But you must not
    expect anything in return. I am here perfectly insulated, and
    this country furnishes but few fellow-labourers, and these are so
    scattered, that we can have but little communication with each
    other, and they are equally in want of information with myself.
    Unfortunately, too, correspondence with England is very slow and
    uncertain, and with France we have not as yet any intercourse at
    all, tho we hope to have it soon....

    “I thank you for the favourable mention you so frequently make of
    my experiments, and have only to remark that in Mr. Nicholson’s
    Journal you say that the conducting power of charcoal was first
    observed by those who made experiments on the pile of Volta;
    whereas it was one of the earliest that I made, and gave an
    account of in my History of Electricity, and in the Philosophical
    Transactions. And in your treatise on the Nitrous Oxide p. 55
    you say, and justly, that I concluded this air to be lighter
    than that of the atmosphere. This, however, was an error in the
    printing that I cannot account for. It should have been _alkaline
    air_, as you will see the experiment necessarily requires.

         “With the greatest esteem, I am Sir, yours sincerely
                                                   “J. PRIESTLEY.”

In Davy’s next contribution, “On the Silex composing the Epidermis, or
External Bark, and contained in other parts of certain Vegetables,”
published in Nicholson’s Journal in the early part of 1800, we find
the evidence of a chastened and contrite spirit. The theme is humble
enough, and the language as sober and sedate as that of Mr. Cavendish.
The chance observation of a child that two bonnet-canes rubbed together
in the dark produced a luminous appearance, led him to investigate the
cause, which he found to reside in the crystallised silica present
in the epidermis. Reeds and grasses, and the straw of cereals, were
also found to be rich in silica, from which he concludes that “the
flint entering into the composition of these hollow vegetables may
be considered as analogous to the bones of animals; it gives to them
stability and form, and by being situated in the epidermis more
effectively preserves their vessels from external injury.” It is
doubtful, however, whether the rigidity of the stems of cereals is
wholly due to the silica they contain.

From a letter to Mr. Davies Gilbert, dated April 10th, 1799, we
learn that he had now begun to investigate the effects of gases in
respiration. In the early part of the year he had removed to a house
in Dowry Square, Clifton, where he had fitted up a laboratory. After
thanking his friend for his critical remarks on his recently published
essays, he says:

    “Your excellent and truly philosophic observations will induce
    me to pay greater attention to all my positions.... I made a
    discovery yesterday which proves how necessary it is to repeat
    experiments. The gaseous oxide of azote is perfectly respirable
    when pure. It is never deleterious but when it contains nitrous
    gas. I have found a mode of obtaining it pure, and I breathed
    to-day, in the presence of Dr. Beddoes and some others, sixteen
    quarts of it for near seven minutes. It appears to support life
    longer than even oxygen gas, and absolutely intoxicated me. Pure
    oxygen gas produced no alteration in my pulse, nor any other
    material effect; whereas this gas raised my pulse upwards of
    twenty strokes, made me dance about the laboratory as a madman,
    and has kept my spirits in a glow ever since. Is not this a proof
    of the truth of my theory of respiration? for this gas contains
    more light in proportion to its oxygen than any other, and I hope
    will prove a most valuable medicine.

    “We have upwards of eighty out-patients in the Pneumatic
    Institution, and are going on wonderfully well.”

This observation of the respirability of nitrous oxide, and of the
effects of its inhalation, was quickly confirmed. Southey, Coleridge,
Tobin (the dramatist), Joseph Priestley, the son of the chemist, the
two Wedgwoods, and a dozen other people of lesser note were induced
to breathe the gas and to record their sensations. The discovery was
soon noised abroad; Dr. Beddoes dispatched a short note to Nicholson’s
Journal, and the fame of the Pneumatic Institution went up by leaps and
bounds.

Maria Edgeworth, who was at the time on a visit to her sister, thus
writes:--

    “A young man, a Mr. Davy, at Dr. Beddoes’, who has applied
    himself much to chemistry, has made some discoveries of
    importance, and enthusiastically expects wonders will be
    performed by the use of certain gases, which inebriate in the
    most delightful manner, having the oblivious effects of Lethe,
    and at the same time giving the rapturous sensations of the
    Nectar of the Gods! Pleasure even to madness is the consequence
    of this draught. But faith, great faith, is I believe necessary
    to produce any effect upon the drinkers, and I have seen some of
    the adventurous philosophers who sought in vain for satisfaction
    in the bag of _Gaseous Oxyd_, and found nothing but a sick
    stomach and a giddy head.”

Laughing-gas, indeed threatened to become, like Priestley’s
dephlogisticated air, “a fashionable article in luxury.” Monsieur
Fiévée, in his “Lettres sur l’Angleterre, 1802,” names it in the
catalogue of follies to which the English were addicted, and says the
practice of breathing it amounted to a national vice!

Davy had no sooner discovered that the gas might be respired, than he
proceeded to attack the whole subject of the chemistry of the oxides
of nitrogen, and of nitrous oxide in particular, and after ten months
of incessant labour he put together the results of his observations in
an octavo volume, entitled, “Researches, Chemical and Philosophical,
chiefly concerning Nitrous Oxide, or Dephlogisticated Nitrous Air,
and its Respiration. By Humphry Davy, Superintendent of the Medical
Institution.” The book appeared in the summer of 1800, and immediately
re-established its author’s character as an experimentalist. Thomson,
in his “History of Chemistry,” says of it: “This work gave him at once
a high reputation as a chemist, and was really a wonderful performance,
when the circumstances under which it was produced are taken into
consideration.” In spite, however, of the eulogies with which it was
welcomed, its sale was never very extensive, and a second edition was
not required. In fact, the work as a whole was hardly calculated to
attract the general public, whose only concern with laughing-gas was in
its powers as an exhilarant. Indeed, this aspect of the question is not
wholly lost on Davy himself, who is careful to point out that “if the
pleasurable effects or medical properties of the nitrous oxide should
ever make it an article of general request, it may be procured with
much less time, labour, and expense than most of the luxuries, or even
necessaries, of life”; and in a footnote he adds. “A pound of nitrate
of ammonia costs 5s. 10d. (its present price is 9d.!). This pound,
properly decomposed, produces rather more than 34 moderate doses of the
air, so that the expense of a dose is about 2d. What fluid stimulus
can be procured at so cheap a rate?”

To the chemical student the book had, and still has, many features of
interest. It contains a number of important facts, based on original
and fairly accurate observation. In the arrangement of these facts
“I have been guided as much as possible,” says their author, “by
obvious and simple analogies only. Hence, I have seldom entered into
theoretical discussions, particularly concerning light, heat, and other
agents, which are known only by isolated effects. Early experience
has taught me the folly of hasty generalisation.” The work is divided
into four main sections. The first chiefly relates to the production
of nitrous oxide, and the analysis of nitrous gas and nitrous acid.
He minutely studies the mode of decomposition of ammonium nitrate
(first observed by Berthollet), and shows that it is an endothermic
phenomenon, varying in character with the temperature and manner of
heating. He is thus led to offer the following _Speculations on the
Decompositions of Nitrate of Ammonia_:--

    “All the phenomena of chemistry concur in proving that the
    affinity of one body, A, for another, B, is not destroyed by
    its combination with a third, C, but only modified; either by
    condensation or expansion, or by the attraction of C for B.
    On this principle the attraction of compound bodies for each
    other must be resolved into the reciprocal attractions of their
    constituents, and consequently the changes produced in them by
    variations of temperature explained from the alterations produced
    in the attractions of those constituents.”

The singular property possessed by ammonium nitrate of decomposing
in several distinct modes according to the rapidity of heating and
the temperature to which the substance is raised, first indicated by
Davy, has been minutely studied by M. Berthelot, who has shown that
this comparatively simple salt may be decomposed in as many as six
different ways. It may be (1) dissociated into gaseous nitric acid and
ammonia; (2) decomposed into nitrous oxide and water; (3) resolved into
nitrogen, oxygen, and water, (4) or into nitric oxide, nitrogen, and
water, (5) or into nitrogen, nitrogen peroxide, and water; or lastly
(6), under the influence of spongy platinum, it may be resolved into
gaseous nitric acid, nitrogen, and aqueous vapour. These different
modes of decomposition may be distinct or simultaneous; or, more
exactly, the predominance of any one of them depends on relative
rapidity and on the temperature at which decomposition is produced.
This temperature is not fixed, but is itself subordinate to the
rapidity of heating (_cf._ Berthelot’s “Explosives and Their Power,”
translated by Hake and Macnab). The assertion of De la Metherie, that
the gas produced by the solution of platinum in nitromuriatic acid was
identical with the dephlogisticated nitrous air of Priestley (nitrous
oxide), led Davy to examine the gaseous products of this reaction more
particularly. He had no difficulty in disproving the statement of the
French chemist; but his observations, although accurate, led him to
no definite conclusion. “It remains doubtful,” he says, “whether the
gas consists simply of highly oxigenated muriatic acid and nitrogen,
produced by the decomposition of nitric acid from the coalescing
affinities of platina and muriatic acid for oxygen; or whether it is
composed of a _peculiar_ gas, analogous to oxigenated muriatic acid and
nitrogen, generated from some unknown affinities.” The real nature of
the gas, which has also been considered by Lavoisier as a particular
species, not hitherto described, was first established by Gay Lussac,
when Davy had himself proved that “oxigenated muriatic acid” was a
simple substance.

In the second section the combinations and composition of nitrous
oxide are investigated, and an account is given of its decomposition
by combustible bodies, and a series of experiments are described which
are now among the stock illustrations of the chemical lecture-room.
As to its composition, he says, “taking the mean estimations from the
most accurate experiments, we may conclude that 100 grains of the known
ponderable matter of nitrous oxide consist of about 36·7 oxygen and
63·3 nitrogen”--no very great disparity from modern numbers, viz. 36·4
oxygen and 63·6 nitrogen. He concludes this section with a short review
of the characteristic properties of the combinations of oxygen and
nitrogen, among which he is led to class atmospheric air.

    “That the oxygen and nitrogen of atmospheric air exist in
    chemical union, appears almost demonstrable from the following
    evidences.

    “1st. The equable diffusion of oxygen and nitrogen through
    every part of the atmosphere, which can hardly be supposed
    to depend on any other cause than an affinity between these
    principles.

    “2dly. The difference between the specific gravity of
    atmospheric air, and a mixture of 27 parts oxygen and 73
    nitrogen, as found by calculation; a difference apparently owing
    to expansion in consequence of combination.”

These “evidences” had already been adduced by others, as stated by
Davy; the first was subsequently disproved by Dalton, the second was
based on inaccurate analyses of air.

To these Davy added two other “proofs” which originated with him:--

    “3dly. The conversion of nitrous oxide into nitrous acid, and
    a gas analogous to common air, by ignition.

    “4thly. The solubility of atmospheric air undecompounded.”

Of these it may be stated that the first is invalid, and the second
not true. Nitrous oxide may, under certain circumstances, give rise
to a mixture of oxygen and nitrogen, but not necessarily in the same
proportion as in common air; and the air boiled out from water has not
the same composition as atmospheric air.

Davy a few years afterwards obtained much clearer views as to the real
nature of the atmosphere, and was, in fact, one of the earliest to
recognise that it is merely a mixture of oxygen and nitrogen.

The third section consists of an account of observations on the
action of nitrous oxide upon animals, and an investigation of the
changes effected in it by respiration; whilst the fourth and last
gives a history of the respirability and of the extraordinary effects
of nitrous oxide, with details of experiments on its powers made by
different individuals.

The last portion of the inquiry--in time of execution the first--is
particularly interesting to the biographer of Davy, not only because
the work in it was originated and carried out by him, but also from the
light it incidentally throws on his character and genius:--

    “A short time,” he says, “after I began the study of chemistry,
    in March 1798, my attention was directed to the dephlogisticated
    nitrous gas of Priestley, by Dr. Mitchell’s Theory of Contagion.”
    “Dr. Mitchell,” he tells us in a foot-note, “attempted to prove
    from some phenomenon connected with contagious diseases, that
    dephlogisticated nitrous gas which he called oxide of septon,
    was the principle of contagion, and capable of producing the
    most terrible effects when respired by animals in the minutest
    quantities, or even when applied to the skin or muscular
    fibre.” “The fallacy of this theory,” he continues, “was soon
    demonstrated by a few coarse experiments made on small quantities
    of the gas procured from zinc and diluted nitrous [nitric] acid.
    Wounds were exposed to its action, the bodies of animals were
    immersed in it without injury; and I breathed it mingled in small
    quantities with common air, without remarkable effects. An
    inability to procure it in sufficient quantities prevented me at
    this time from pursuing the experiments to any greater extent. I
    communicated an account of them to Dr. Beddoes.”

In the early part of April, 1799, he obtained nitrous oxide in a state
of purity, and, as already stated, made the attempt to respire it.

    “I was aware,” he says, “of the danger of this experiment. It
    certainly would never have been made if the hypothesis of Dr.
    Mitchell had in the least influenced my mind. I thought that
    the effects might be possibly depressing and painful, but there
    were many reasons which induced me to believe that a single
    inspiration of a gas apparently possessing no immediate action on
    the irritable fibre, could neither destroy nor immediately injure
    the powers of life.”

The experiment was made: the gas passed into the bronchia without
stimulating the glottis, and produced no uneasy feeling in the lungs.
There was a sense of fulness in the head accompanied with loss of
distinct sensation and voluntary power--a feeling analogous to that
produced in the first stage of intoxication, but unattended by
pleasurable sensation. In company with Dr. Beddoes the experiment was
repeated, with the following results:--

    “Having previously closed my nostrils and exhausted my lungs,
    I breathed four quarts of nitrous oxide from and in to a silk
    bag. The first feelings were similar to those produced in the
    last experiment; but in less than half a minute, the respiration
    being continued, they diminished gradually, and were succeeded
    by a sensation analogous to gentle pressure on all the muscles
    attended by a highly pleasurable thrilling, particularly in the
    chest and the extremities. The objects around me became dazzling,
    and my hearing more acute. Towards the last inspirations,
    the thrilling increased, the sense of muscular power became
    greater, and at last an irresistible propensity to action was
    indulged in; I recollect but indistinctly what followed; I know
    that my motions were various and violent. These effects very
    soon ceased after respiration. In ten minutes I had recovered
    my natural state of mind. The thrilling in the extremities
    continued longer than the other sensations. This experiment was
    made in the morning; no langour or exhaustion was consequent,
    my feelings throughout the day were as usual, and I passed the
    night in undisturbed repose. The next morning the recollections
    of the effects of the gas were very indistinct, and had not
    remarks written immediately after the experiment recalled them
    to my mind I should have even doubted of their reality. I was
    willing indeed to attribute some of the strong emotion to the
    enthusiasm, which I supposed must have been necessarily connected
    with the perception of agreeable feelings, when I was prepared to
    experience painful sensations. Two experiments, however, made in
    the course of this day, with scepticism, convinced me that the
    effects were solely owing to the specific operation of the gas.”

Having thus ascertained the powers of the gas, he made many experiments
to ascertain the length of time it might be breathed with safety, its
action on the pulse, and its general effects on the health when often
respired.

After a number of experiments made to determine its effect in allaying
fatigue, in inducing sleep, or in alleviating the after-effects of
vinous intoxication, he resolved

    “to breathe the gas for such a time and in such quantities as to
    produce excitement equal in duration and superior in intensity to
    that occasioned by high intoxication from opium or alcohol.”

For this purpose he was enclosed in an air-tight or box-chamber, into
which from time to time, by the help of Dr. Kinglake, successive
quantities of twenty quarts of nitrous oxide were introduced. As he
breathed the gas, he found that his temperature and pulse gradually
increased. He experienced a generally diffused warmth without the
slightest moisture of the skin, a sense of exhilaration similar to that
produced by a small dose of wine, and disposition to muscular motion
and to merriment. Luminous points seemed frequently to pass before his
eyes, his hearing became more acute, and he felt a pleasant lightness
and power of exertion in the muscles; and, on account of the great
desire of action, rest was painful. After having been in the box for
an hour and a quarter he began to respire twenty quarts of unmingled
nitrous oxide. What followed is best described in his own words:--

    “A thrilling, extending from the chest to the extremities, was
    almost immediately produced. I felt a sense of tangible extension
    highly pleasurable in every limb; my visible impressions were
    dazzling, and apparently magnified, I heard distinctly every
    sound in the room, and was perfectly aware of my situation. By
    degrees, as the pleasurable sensations increased, I lost all
    connection with external things; trains of vivid visible images
    rapidly passed through my mind, and were connected with words
    in such a manner, as to produce perceptions perfectly novel.
    I existed in a world of newly connected and newly modified
    ideas: I theorised, I imagined that I made discoveries. When I
    was awakened from this semi delirious trance by Dr. Kinglake,
    who took the bag from my mouth, indignation and pride were the
    first feelings produced by the sight of the persons about me. My
    emotions were enthusiastic and sublime, and for a minute I walked
    round the room perfectly regardless of what was said to me. As
    I recovered my former state of mind I felt an inclination to
    communicate the discoveries I had made during the experiment. I
    endeavoured to recall the ideas: they were feeble and indistinct;
    one collection of terms however presented itself; and with a most
    intense belief and prophetic manner, I exclaimed to Dr. Kinglake,
    ‘_Nothing exists but thoughts! The universe is composed of
    impressions, ideas, pleasures and pains!_’”

As might be anticipated, the friend of Coleridge and Southey, himself a
youth of sensibility and poetic feeling, was curious to learn whether
this wonderful gas would increase his stock of the divine afflatus. He
walked amidst the scenery of the Avon, “rendered exquisitely beautiful
by bright moonshine,” and, with a mind filled with pleasurable
feelings, he breathed the gas, and we have as a consequence the
following effusion:--

    “Not in the ideal dreams of wild desire
      Have I beheld a rapture-wakening form:
    My bosom burns with no unhallow’d fire,
      Yet is my cheek with rosy blushes warm;
    Yet are my eyes with sparkling lustre fill’d;
      Yet is my mouth replete with murmuring sound;
    Yet are my limbs with inward transports fill’d,
      And clad with new-born mightiness around.”

Whether, as the result of this effort, Davy ever again essayed to
tempt the muse when under the influence of nitrous oxide is doubtful.
Nowadays the gas is too frequently associated with unhappy memories of
the dentist’s chair to call up pleasurable associations in a poet’s
mind.

Davy concludes his memoir with some cautious speculations as to the
mode of action of nitrous oxide. That it acts on the blood he was well
aware, but it has been left for subsequent research to determine in
what manner. He points out that “as nitrous oxide in its extensive
operation appears capable of destroying physical pain, it may probably
be used with advantage during surgical operations in which no great
effusion of blood takes place.” As is well known, nitrous oxide is now
one of the commonest anæsthetic agents.

As regards the general question how far the gases are likely to
subserve the interests of medicine, he is very guarded.

    “Pneumatic chemistry,” he says, “in its application to medicine
    is an art in infancy, weak, almost useless, but apparently
    possessed of capabilities of improvement. To be rendered strong
    and mature, she must be nourished by facts, strengthened by
    exercise, and cautiously directed in the application of her
    powers by rational scepticism.”

Davy’s success with nitrous oxide led him to attempt to respire other
gases--such as hydrogen, nitric oxide, carbonic acid--with in one
or two cases almost fatal consequences. On one occasion he tried to
breathe water-gas, made by passing steam over charcoal, and was with
difficulty brought to life again. These deleterious experiments,
carried on with all the ardour and impetuosity of his nature, and
at the expense of much nervous energy, reacted prejudicially on his
health, and he was obliged to seek relaxation and quiet in the pure
atmosphere of his native place.

With the approach of winter he was back again in Bristol, with health
restored and vigour renewed. The following letter to Mr. Davies Gilbert
is interesting as fixing the time at which he entered on the path of
inquiry which was to lead him to his greatest triumphs:--

            “Pneumatic Institution, _Oct. 20, 1800_.

    “In pursuing experiments on galvanism, during the last two
    months, I have met with unexpected and unhoped-for success. Some
    of the new facts on this subject promise to afford instruments
    capable of destroying the mysterious veil which Nature has thrown
    over the operations and properties of ethereal fluids.

    “Galvanism I have found, by numerous experiments, to be _a
    process purely chemical_, and to depend wholly on the oxidation
    of metallic surfaces, having different degrees of electric
    conducting power.

    “Zinc is incapable of decomposing _pure_ water; and if the zinc
    plates be kept moist with _pure_ water, the galvanic pile does
    not act; but zinc is capable of oxidating itself when placed
    in contact with water, holding in solution either oxygen,
    atmospheric air, or nitrous or muriatic acid, &c.; and under such
    circumstances the galvanic phenomena are produced, and their
    intensity is in proportion to the rapidity with which the zinc is
    oxidated.

    “The galvanic pile only acts for a few minutes, when introduced
    into hydrogen, nitrogen, or hydrocarbonate [the gas obtained by
    the action of steam on charcoal]; that is, only as long as the
    water between its plates holds some oxygen in solution; immerse
    it for a few moments in water containing air, and it acts again.

    “It acts very vividly in oxygen gas, and less so in the
    atmosphere. When its plates are moistened by marine acid, its
    action is very powerful, but infinitely more so when nitrous
    [nitric] acid is employed. Five plates with nitrous [nitric] acid
    gave sparks equal to those of the common pile. From twenty plates
    the shock was insupportable.

    “I had almost forgotten to mention, that charcoal is a good
    galvanic exciter, and decomposes water, like the metals, in the
    pile; but I must stop, without being able to expatiate on the
    connection which is now obvious between galvanism and some of the
    phenomena of organic motion....

    “I remain with sincere respect and affection, yours

            “HUMPHRY DAVY.”

To his mother he writes:--

            “Hotwells, _November 19, 1800_.

    “MY DEAR MOTHER,--Had I believed that my silence of six weeks
    would have given you a moment’s uneasiness, I should have written
    long ago. But I have been engaged in my favourite pursuit of
    experimenting, and in endeavouring to amuse two of my friends
    who have spent some days at the Institute. One of them is your
    quondam lodger, Gregory Watt, who desired to be kindly remembered
    to you and the family....

    “Accept my affectionate thanks for your presents. I have received
    them all, and I have made a good use of them all. Several
    times has a supper on the excellent marinaded pilchards made
    me recollect former times, when I sat opposite to you, my dear
    mother, in the little parlour, round the little table eating of
    the same delicious food, and talking of future unknown things.
    Little did I then think of my present situation, or of the mode
    in which I am, and am to be, connected with the world. Little did
    I then think that I should ever be so long absent from the place
    of my birth as to feel longings so powerful as those I now feel
    for visiting it again....

    “I shall see with heartfelt pleasure the time approaching when
    I shall again behold my first home--when I shall endeavour
    to repay some of the debts of gratitude I owe to you, to the
    Doctor [Tonkin], and to my aunts. My next visit shall not be so
    short a one as the last. I will stay with you at least two or
    three months. You have let half your house. Have you a bed-room
    reserved for me, and a little room for a laboratory? Which part
    have you let? When I come to Penzance we will settle all about
    John; till then I should like for him to learn French and Latin
    with Mr. Dugart. The expense of this or any other part of his
    education I will be glad to defray. Do not by any means put him
    with Mr. Coryton.... I will write to Kitty in the course of next
    month. I am glad to hear Grace is better....

    “All in the way of progress goes on nobly. My health was never
    better than it has been since I left Cornwall last. I shall be
    very glad to hear from you soon. You have a hundred objects to
    write about interesting to me. I can only write of myself....
    Love to Kitty, Grace, Betsy and John.

    “Farewell, my dear mother. I am your affectionate son

            “H. DAVY.”

The following letter is to his old friend and benefactor, Mr. John
Tonkin:--

            “Dowry Square, Clifton, _Jan. 12, 1801_.

    “RESPECTED SIR, ... Natural philosophy has lately been enriched
    with many curious discoveries, amongst which galvanism, a
    phenomenon that promises to unfold to us some of the laws of our
    nature is one of the most important. In medicine, the inoculation
    for the cow-pox is becoming general, not in England alone, but
    over the whole of Europe; and taking circumstances as they
    now stand, it promises gradually to annihilate small-pox. My
    discoveries relating to the nitrous oxide, the pleasure-producing
    air, are beginning to make some noise; the experiments have
    been repeated, with the greatest success, by the professors
    of the University of Edinburgh, who have taken up the subject
    with great ardour; and I have received letters of thanks and of
    praises for my labours from some of the most respectable of the
    English philosophers. I am sorry to be so much of an egotist;
    yet I cannot speak of the Pneumatic Institution and its success
    without speaking of myself. Our patients are becoming daily
    more numerous, and our Institution, in spite of the political
    odium attached to its founder, is respected, even in the trading
    city of Bristol.... I am at this moment very healthy and very
    happy; I have had great success in my experiments and I gain a
    competence by my pursuits, at the same time that I am (in hopes
    at least) doing something towards promoting the public good. If
    I feel any anxiety, it is that of being removed so far from you,
    my mother, and my relations and friends. If I was nearer, I would
    endeavour to be useful to you: I would endeavour to pay some of
    the debts of gratitude, I owe to you, my first protector and
    earliest friend. As it is, I must look forward to a futurity that
    will enable me to do this; but, believe me, wherever I am, and
    whatever may be my situation, I shall never lose the remembrance
    of obligations conferred on me, or the sense of gratitude which
    ought to accompany them.

    “I remain, respected Sir, with unfeigned duty and affection, yours

            “H. DAVY.”




CHAPTER III.

THE PNEUMATIC INSTITUTION, BRISTOL, 1798-1801 (_continued_).


Perhaps at no time of his life was Davy more keenly sensible of the
joy of living than at this period--“in the flower and freshness of his
youth,” as Southey says. That he was eager, active, buoyant, happy, is
obvious from his letters. He had the sweet consciousness of success,
and all the sweeter that it had so quickly followed the bitterness of
disappointment. He had been able to measure himself against some of
the ablest minds of the time--of men who were making the intellectual
history of the early part of this century--and the comparison, we may
be sure, was not altogether unpleasing to him.

The love of fame--“the honourable meed of the applause of enlightened
men,” as he called it--was his ruling passion and the motive principle
of his life. As his experience and the range of his knowledge widened,
he felt a growing conviction that with health and strength he need set
no bounds to the limits of his ambition.

Of the impression he made on others, and of the influence and power
he exerted on minds far more matured than his own, we have abundant
evidence in the letters of his contemporaries. Miss Edgeworth’s
good-humoured patronage quickly passed into amazement and ended in awe.
Writing to William Taylor of Norwich, Southey calls Davy “a miraculous
young man, whose talents I can only wonder at.” Amos Cottle, poet and
publisher, to whom he was introduced shortly after his arrival at
Bristol, says of him in the “Reminiscences of Coleridge and Southey”:--

    “I was much struck with the intellectual character of his face.
    His eye was piercing, and when not engaged in converse, was
    remarkably introverted, amounting to absence, as though his mind
    had been pursuing some severe train of thought scarcely to be
    interrupted by external objects; and, from the first interview
    also, his ingenuousness impressed me as much as his mental
    superiority.”

Cottle on one occasion said to Coleridge, “During your stay in London
you doubtless saw a great many of what are called the cleverest
men--how do you estimate Davy in comparison with these?” Mr.
Coleridge’s reply was strong but expressive: “Why, Davy can eat them
all! There is an energy, an elasticity, in his mind which enables him
to seize on and analyse all questions, pushing them to their legitimate
consequences. Every subject in Davy’s mind has the principle of
vitality. Living thoughts spring up like turf under his feet.” It can
hardly be doubted that Davy’s connection with that remarkable literary
coterie which made its headquarters in the neighbourhood of Bristol
in the last year of the eighteenth century, strongly stimulated his
intellectual activity. In one of his poems written at this period he
speaks of having

                      “felt the warmth,
    The gentle influence of congenial souls,
    Whose kindred hopes have cheer’d me”

That these “congenial souls” in turn felt his influence no less
strongly will be apparent from the following letters--the first from
Southey, who then resided at Westbury, the others from Coleridge, who
had just removed to the Lake country:--

            “Thursday, _May 4th, 1799_.

    “Your ‘Mount’s Bay,’ my dear Davy, disappointed me in its length.
    I expected more, and wished more, because what there is is good;
    there is a certain swell, an elevation in the flow of the blank
    verse, which, I do not know how, produces an effect like the
    fulness of an organ-swell upon the feeling. I have felt it from
    the rhythm of Milton, and sometimes of Akenside, a pleasure
    wholly independent from that derived from the soul of the poetry,
    arising from the beauty of the body only. I believe a man who did
    not understand a word of it would feel pleasure and emotion at
    hearing such lines read with the tone of a poet....

    “I must not press the subject of poetry upon you, only do not
    lose the feeling and the habit of seeing all things with a poet’s
    eye; at Bristol you have a good society, but not a man who knows
    anything of poetry. Dr. Beddoes’ taste is very pessimism. Cottle
    only likes what his friends and himself write. Every person
    fancies himself competent to pronounce upon the merits of a poem,
    and yet no trade requires so long an apprenticeship, or involves
    the necessity of such multifarious knowledge....

    “At Lymouth I saw Tobin’s friend Williams who opened upon me
    with an account of the gaseous oxide. I had the advantage of
    him, having felt what he it seems had only seen. Lymouth where
    he is fixed is certainly the most beautiful place I have seen in
    England, so beautiful that all the after-scenes come flat and
    uninteresting. The Valley of Stones is about half a mile distant,
    a strange and magnificent place, which ought to have filled
    the whole neighbourhood with traditions of giants, devils, and
    magicians, but I could find none, not even a lie preserved. I
    know too little of natural history to hypothesize upon the cause
    of this valley; it appeared to me that nothing but water could
    have so defleshed and laid bare the bones of the earth--that
    any inundation which could have overtopped these heights must
    have deluged the kingdom; but the opposite hills are clothed
    with vegetable soil and verdure, therefore the cause must have
    been partial--a waterspout might have occasioned it perhaps--and
    there my conjectures rested, or rather took a new direction to
    the pre-Adamite kings, the fiends who married Diocletian’s fifty
    daughters--their giant progeny, old Merlin and the builders of
    the Giant’s Causeway.

    “For the next Anthology I project a poem on our Clifton rocks;
    the scenery is fresh in my sight, and these kind of poems derive
    a more interesting cast as _recollections_ than as immediate
    pictures. Farewell. Yours truly,

            “ROBERT SOUTHEY.”

       *       *       *       *       *

            “Keswick, Friday Evening, _July 25, 1800_.

    “MY DEAR DAVY,--Work hard, and if success do not dance up like
    the bubbles in the salt (with the spirit lamp under it[C]) may
    the Devil and his dam take success! My dear fellow! from the
    window before me there is a great _camp_ of mountains. Giants
    seem to have pitched their tents there. Each mountain is a
    giant’s tent, and how the light streams from them! Davy! I _ache_
    for you to be with us.

    “W. Wordsworth is such a lazy fellow, that I bemire myself by
    making promises for him: the moment I received your letter, I
    wrote to him. He will, I hope, write immediately to Biggs and
    Cottle. At all events, these poems must not as yet be delivered
    up to them, because that beautiful poem, ‘The Brothers,’ which I
    read to you in Paul Street, I neglected to deliver to you, and
    that must begin the volume. I trust, however, that I have invoked
    the sleeping bard with a spell so potent, that he will awake and
    deliver up that Sword of Argantyr, which is to rive the enchanter
    _Gaudyverse_ from his crown to his feet.

    “What did you think of that case I translated for you from the
    German? That I was a well-meaning sutor who had ultra-crepidated
    with more zeal than wisdom!! I give myself credit for that word
    ‘ultra-crepidated,’ it started up in my brain like a creation....

    “We drank tea the night before I left Grasmere, on the island
    in that lovely lake; our kettle swung over the fire, hanging
    from the branch of a fir-tree, and I lay and saw the woods, and
    mountains, and lake all trembling, and as it were idealized
    through the subtle smoke, which rose up from the clear red embers
    of the fir-apples which we had collected; afterwards we made a
    glorious bonfire on the margin, by some elder bushes, whose twigs
    heaved and sobbed in the uprushing column of smoke, and the image
    of the bonfire, and of us that danced round it, ruddy, laughing
    faces in the twilight; the image of this in a lake, smooth as
    that sea, to whose waves the Son of God had said, _Peace!_ May
    God, and all his sons, love you as I do.

            “S. T. COLERIDGE.

    “Sara desires her kind remembrances. Hartley is a spirit that
    dances on an aspen leaf: the air that yonder sallow-faced and
    yawning tourist is breathing, is to my babe a perpetual nitrous
    oxide....”

    [C] Doubtless an allusion to the decomposition of ammonium
        nitrate, which Coleridge had frequently seen Davy effect.

       *       *       *       *       *

            “Thursday night, _Oct. 9, 1800_.

    “MY DEAR DAVY,--I was right glad, glad with a _stagger_ of the
    heart, to see your writing again. Many a moment have I had all
    my France and England curiosity suspended and lost, looking in
    the advertisement front column of the Morning Post Gazetteer,
    for _Mr. Davy’s Galvanic habitudes of charcoal_. Upon my soul,
    I believe there is not a letter in those words round which a
    world of imagery does not circumvolve; your room, the garden, the
    cold bath, the moonlit rocks ... and dreams of wonderful things
    attached to your name.... I pray you do write to me immediately,
    and tell me what you mean by the possibility of your assuming a
    new occupation; have you been successful to the extent of your
    expectations in your late chemical inquiries?...

    “As to myself, I am doing little worthy the relation. I write
    for Stuart in the Morning Post, and I am compelled by the god
    Pecunia, which was one name of the supreme Jupiter, to give a
    volume of letters from Germany, which will be a decent _lounge_
    book, and not an atom more. The Christabel was running up to
    1,300 lines, and was so much admired by Wordsworth, that he
    thought it indelicate to print two volumes with his name, in
    which so much of another man’s was included.... We mean to
    publish the Christabel, therefore, with a long blank-verse
    of Wordsworth’s, entitled The Pedlar [afterwards changed to
    ‘The Excursion’]. I assure you I think very differently of
    _Christabel_. I would rather have written Ruth and Nature’s Lady,
    than a million such poems. But why do I calumniate my own spirit
    by saying I would rather? God knows it is as delightful to me
    that they _are_ written....

    “Wordsworth is fearful you have been much teazed by the printers
    on his account, but you can sympathise with him....

    “When you write, and do write soon, tell me how I can get your
    Essay on the Nitrous Oxide.... Are your galvanic discoveries
    important? What do they lead to? All this is _ultra-crepidation_,
    but would to heaven I had as much knowledge as I have sympathy!...

            “God bless you! Your most affectionate
                                  “S. T. COLERIDGE.”

       *       *       *       *       *

            “Greta Hall, Tuesday night, _Dec. 2, 1800_.

    “MY DEAR DAVY,--By an accident I did not receive your letter till
    this evening. I would that you had added to the account of your
    indisposition the probable causes of it. It has left me anxious
    whether or no you have not exposed yourself to unwholesome
    influences in your chemical pursuits. There are _few_ beings both
    of hope and performance, but few who combine the ‘are’ and the
    ‘will be.’ For God’s sake, therefore, my dear fellow, do not rip
    open the bird that lays the golden eggs....

    “At times, indeed, I would fain be somewhat of a more tangible
    utility than I am; but so I suppose it is with all of us--one
    while cheerful, stirring, feeling in resistance nothing but a
    joy and a stimulus; another while drowsy, self-distrusting,
    prone to rest, loathing our own self-promises, withering our own
    hopes--our hopes, the vitality and cohesion of our being?

    “I purpose to have Christabel published by itself--this I publish
    with confidence--but my travels in Germany come from me now with
    mortal pangs.

    “Wordsworth has nearly finished the concluding poem. It is of
    a mild, unimposing character, but full of beauties to those
    short-necked men who have their hearts sufficiently near their
    heads--the relative distance of which (according to citizen
    Tourder, the French translator of Spallanzani) determines the
    sagacity or stupidity of all bipeds and quadrupeds....

              “God love you!
            “S. T. COLERIDGE.”

“No man ever had genius who did not aim to execute more than he was
able.” So wrote Davy in one of his early note-books; and of no man was
this more true than of Davy himself. Busy as he was with experimental
research at this time, his mind was by no means wholly occupied with
it. Change of mental occupation was, indeed, a necessity to him. At
no period of his life could he exercise that power of sustained and
concentrated thought which so strikingly characterised Newton or Dalton
or Faraday. The following scheme of intellectual work which he marked
out for himself shortly after his arrival in Bristol, is characteristic
of the restless, changeful activity of his mind:--

“_Resolution_: To work two hours with pen before breakfast on the
‘Lover of Nature’; and ‘The Feelings of Eldon’ from six till eight;
from nine till two in experiments; from four to six, reading; seven
till ten, metaphysical reading (_i.e._ ‘System of the Universe’).”
The “Lover of Nature” and “The Feelings of Eldon” were two among the
half-dozen romances he projected at one time or other, and of which
fragments were found amongst his papers, and by means of which he
intended to inculcate his own metaphysical and philosophical ideas
and his views on education and the development of character. Dr.
John Davy tells us that his note-books at this period were not less
characteristic; “they contain, mixed together, without the least regard
to order, schemes and minutes of experiments, passing thoughts of
various kinds, lines of poetry (but these are in small proportion),
fragments of stories and romances, metaphysical fragments, and sketches
of philosophical essays.”

Many of these jottings and reflections are evidently based on his own
experience, and hence serve to illustrate his temperament and the
workings of his mind. In an essay on “Genius,” written at this time, he
says:--

    “Great powers have never been exerted independent of strong
    feelings. The rapid arrangements of ideas, from their various
    analogies to the equally rapid comparisons of these analogies,
    with facts uniformly occurring during the progress of discovery,
    have existed only in those minds where the agency of strong and
    various motives is perceived--of motives modifying each other,
    mingling with each other, and producing that fever of emotion,
    which is the joy of existence and the consciousness of life.”

The following extracts relate to science and philosophy:--

    “Philosophy is simple and intelligible. We owe confused systems
    to men of vague and obscure ideas.”

    “We ought to reason from effects alone. False philosophy has
    uniformly depended upon making use of words which signify no
    definite ideas.”

    “Experimental science hardly ever affords us more than
    approximations to truth; and whenever many agents are concerned
    we are in great danger of being mistaken.”

    “Scepticism in regard to theory is what we ought most rigorously
    to adhere to.”

    “The feeling generally connected with new facts enables us to
    reason more rapidly upon them, and is peculiarly active in
    calling up analogies.”

    “Probabilities are the most we can hope for in our
    generalisation, and whenever we can trace the connection
    of a series of facts, without being obliged to imagine
    certain relations, we may esteem ourselves fortunate in our
    approximations.”

    “One use of physical science is, that it gives definite ideas.”

To the same period belongs the sketch or plan of a poem, in blank
verse, in six books, on the deliverance of the Israelites from Egypt,
which either Southey or Coleridge had proposed to him as a joint-work,
fragments of which are to be found amongst the note-books.

Towards the end of 1800 Davy’s visions of future greatness began
to take more definite shape. This is hinted at in the letter from
Coleridge of October 9th, 1800, already given, and also in one to
his mother, dated September 27th, 1800, in which he says, “My future
prospects are of a very brilliant nature, and they have become more
brilliant since I last wrote to you; but wherever there is uncertainty
I shall refrain from anticipating.”

In a few months the uncertainty was practically at an end.

He had been drawn into the great vortex called London, “full,” as he
says in a letter to Hope, “of the expectation of scientific discovery
from the action of mind upon mind in this great hot-bed, of human
power.” He thus informs his mother:--

            “_31st January, 1801._

    “MY DEAR MOTHER,--During the last three weeks I have been very
    much occupied by business of a very serious nature. This has
    prevented me from writing to you, to my aunt, and to Kitty. I
    now catch a few moments only of leisure to inform you that I
    am exceedingly well, and that I have had proposals of a very
    flattering nature to induce me to leave the Pneumatic Institution
    for a permanent establishment in London.

    “You have perhaps heard of the Royal Philosophical Institution,
    established by Count Rumford, and others of the aristocracy. It
    is a very splendid establishment, and wants only a combination of
    talents to render it eminently useful.

    “Count Rumford has made proposals to me to settle myself there,
    with the present appointment of assistant lecturer on chemistry,
    and experimenter to the Institute; but this only to prepare the
    way for my being in a short time sole professor of chemistry,
    &c.; an appointment as honourable as any scientific appointment
    in the kingdom, with an income of at least 500_l_ a year.

    “I write to-day to get the specific terms of the present
    appointment, when I shall determine whether I shall accept of
    it or not. Dr. Beddoes has honourably absolved me from all
    engagements at the Pneumatic Institution, provided I choose to
    quit it. However, I have views here which I am loath to leave,
    unless for very great advantages.

    “You will all, I dare say, be glad to see me getting amongst the
    _Royalists_, but I will accept of no appointment except upon the
    sacred terms of _independence_....

            “I am your most affectionate son
                                    “H. DAVY.”

In the middle of February he was in London negotiating with Rumford. He
wrote to his mother, “His proposals have not been unfair, and I have
nearly settled the business.” How the business was actually settled
appears from the following extract from the Minute Book of the Royal
Institution of a resolution adopted at a Meeting of the Managers on
February 16th, 1801:--

    “Resolved--That Mr. Humphry Davy be engaged in the service of the
    Royal Institution, in the capacities of Assistant Lecturer in
    Chemistry, Director of the Laboratory, and Assistant Editor of
    the Journals of the Institution, and that he be allowed to occupy
    a room in the house, and be furnished with coals and candles; and
    that he be paid a salary of one hundred guineas per annum.”

He returned to Bristol to hand over his charge of the Pneumatic
Institution, and to take leave of his many friends in that city.
The following letter to Mr. Davies Gilbert is interesting and
characteristic:--

            “Hotwells, _March 8th, 1801_.

    “I cannot think of quitting the Pneumatic Institution, without
    giving you intimation of it in a letter; indeed, I believe
    I should have done this some time ago, had not the hurry of
    business, and the fever of emotion produced by the prospect of
    novel changes in futurity, destroyed to a certain extent my
    powers of consistent action.

    “You, my dear Sir, have behaved to me with great kindness, and
    the little ability I possess you have very much contributed to
    develope; I should therefore accuse myself of ingratitude were I
    to neglect to ask your approbation of the measures I have adopted
    with regard to the change of my situation, and the enlargement of
    my views in life.

    “In consequence of an invitation from Count Rumford, given to
    me with some proposals relative to the Royal Institution, I
    visited London in the middle of February, where, after several
    conferences with that gentleman, I was invited by the Managers of
    the Royal Institution to become the Director of their laboratory,
    and their Assistant Professor of Chemistry; at the same time I
    was assured that, within the space of two or three seasons, I
    should be made sole Professor of Chemistry, still continuing
    Director of the laboratory.

    “The immediate emolument offered was sufficient for my wants;
    and the sole and uncontrolled use of the apparatus of the
    Institution, for private experiments, was to be granted me. The
    behaviour of Count Rumford, Sir Joseph Banks, Mr. Cavendish, and
    the other principal managers, was liberal and polite; and they
    promised me any apparatus that I might need for new experiments.

    “The time required to be devoted to the services of the
    Institution was but short, being limited chiefly to the winter
    and spring. The emoluments to be attached to the office of sole
    Professor of Chemistry are great; and, above all, the situation
    is permanent, and held very honourable.

    “These motives, joined to the approbation of Dr. Beddoes, who
    with great liberality has absolved me from my engagements at
    the Pneumatic Institution, and the strong wishes of most of my
    friends in London and Bristol, determined my conduct.

    “Thus I am quickly to be transferred to London, whilst my sphere
    of action is considerably enlarged, and as much power as I could
    reasonably expect, or even wish for at my time of life, secured
    to me without the obligation of labouring at a profession.

    “The Royal Institution will, I hope, be of some utility to
    Society. It has undoubtedly the capability of becoming a great
    instrument of moral and intellectual improvement. Its funds
    are very great. It has attached to it the feelings of a great
    number of people of fashion and property, and consequently may
    be the means of employing, to useful purposes, money which
    would otherwise be squandered in luxury, and in the production
    of unnecessary labour. Count Rumford professes that it will be
    kept distinct from party politics; I sincerely wish that such
    may be the case, though I fear it. As for myself, I shall become
    attached to it full of hope, with the resolution of employing all
    my feeble powers towards promoting its true interests.

    “So much of my paper has been given to pure egotism, that I have
    but little room left to say anything concerning the state of
    science....

    “Here, at the Pneumatic Institution, the nitrous oxide has
    evidently been of use. Dr. Beddoes is proceeding in the execution
    of his great popular physiological work, which, if it equals the
    plan he holds out, ought to supersede every work of the kind.

    “I have been pursuing Galvanism with labour, and some success. I
    have been able to produce galvanic power from simple plates, by
    effecting on them different oxidating and de-oxidating processes;
    but on this point I cannot enlarge in the small remaining space
    of paper....

    “It will give me sincere pleasure to hear from you, when you are
    at leisure. After the 11th I shall be in town--my direction,
    Royal Institution, Albemarle Street. I am, my dear friend, with
    respect and affection,

            “Yours,
              “HUMPHRY DAVY.”

With Davy’s departure we, too, may take our leave of the Pneumatic
Institution. Like most of Dr. Beddoes’s performances, it--to use Davy’s
words--failed to equal the plan its projector held out. It struggled
on for awhile, living on such success as Davy had brought it, and
ultimately died of inanition. Its founder ended his days a disappointed
man, and on his deathbed wrote to his former assistant, in connection
with whom his memory mainly lives, “like one who has scattered abroad
the _Avena fatua_ of knowledge, from which neither branch, nor blossom,
nor fruit, has resulted, I require the consolations of a friend.”




CHAPTER IV.

THE ROYAL INSTITUTION.


The Royal Institution, as originally conceived, was an establishment
for the benefit of the poor. It was founded at the close of the last
century by Benjamin Thomson, a Royalist American in the service of
the Elector Palatine of Bavaria, by whom he was created a Count of
the Holy Roman Empire. Count Rumford, as he is commonly called, was a
practical philanthropist and a man of science, best known to this age
by his association with the present-day doctrine of the nature of heat;
and to his contemporaries, by his constant efforts to apply science to
domestic economy. In 1796 Rumford put forth a “proposal for forming
in London by private subscription an establishment for feeding the
poor, and giving them useful employment, and also for furnishing food
at a cheap rate to others who may stand in need of such assistance,
connected with an institution for introducing and bringing forward
into general use new inventions and improvements, particularly such
as relate to the management of heat and the saving of fuel, and to
various other mechanical contrivances by which domestic comfort and
economy may be promoted.” Rumford, as he says in one of his letters
to Thomas Bernard--another practical philanthropist, and one of his
earliest associates in the undertaking here referred to--was “deeply
impressed with the necessity of rendering it _fashionable_ to care for
the poor and indigent.” The immediate result was the foundation of
the Society for Bettering the Condition of the Poor; but as regards
the associated Institution, it was eventually considered that it would
be “too conspicuous, and too interesting and important, to be made _an
appendix_ to any other existing establishment, and consequently it must
stand alone, and on its own proper basis.”

In 1799, Rumford conferred with the Committee of the Society for
Bettering the Condition of the Poor as to the steps to be taken to
found, “by private subscription, a public institution for diffusing
the knowledge and facilitating the general and speedy introduction of
new and useful mechanical inventions and improvements; and also for
teaching, by regular courses of philosophical lectures and experiments,
the applications of the new discoveries in science to the improvement
of arts and manufactures, and in facilitating the means of procuring
the comforts and conveniences of life.” The Institution was duly
launched in March, 1799, with Sir Joseph Banks as Chairman of Managers,
Count Rumford as Secretary, and Mr. Thomas Bernard, the promoter of
the Institution for the Protection and Instruction of Climbing Boys,
and of the Society for the Relief of Poor Neighbours in Distress,
as Treasurer. The second volume of the “Reports of the Society for
Bettering the Condition of the Poor” contains a long account of the
Institution, “so far as it may be expected to affect the poor,” from
the pen of Mr. Bernard, concerning which Dr. Bence Jones, a former
Secretary of the Institution, drily remarks, “It is difficult to
believe that the Royal Institution of the present day was ever intended
to resemble the picture given of it in this Report.”

Rumford, from the outset, threw himself with great zeal and ardour
into the work of organising and starting the Institution, and it was
mainly by his energy and administrative ability that so speedy a
beginning was made. Mr. Mellish’s house in Albemarle Street was bought,
and its apartments were quickly transformed into lecture rooms, model
rooms, library, offices, etc. In May “a good cook was engaged for the
improvement of culinary advancement--one object, and not the least
important--for the Royal Institution.” Rumford was requested by the
Managers to live in the house, to superintend the servants, to preserve
order and decorum, and to control the expenses of housekeeping.

Towards the end of 1799 Dr. Garnett was secured as Lecturer and
Scientific Secretary. Thomas Garnett, a physician, who at one time
practised at Harrogate, and who is known to chemists for his researches
into the composition of the Harrogate mineral waters, was at the time
Professor of Chemistry and Experimental Philosophy at Anderson’s
Institution in Glasgow. He had a considerable reputation as a lecturer,
on the strength of which he was invited by Rumford to come to London.
Garnett’s lectures began in March, 1800, in what is now the upper
Library of the Institution, and which had been fitted up to accommodate
the greatest possible number of auditors “with a greater deference to
their curiosity than to their convenience.”

Although not altogether unsuccessful at the Institution, Garnett--in
spite of “the Northern accent which he still retained in a slight
degree, and which rendered his voice somewhat inharmonious to a London
audience”--was hardly the type of man required for such a place,
and differences soon arose between him and Rumford. To add to his
difficulties he had, just prior to his removal from Glasgow, lost
his wife, and the event seems to have wholly unnerved him. He grew
listless and melancholy; and eventually, in 1801, he was called upon
to resign. After leaving the Institution, he struggled on for a time,
giving courses of scientific lectures in his own house, and at Tom’s
Coffee-House in the City, and seeking for practice as a physician. Sick
in mind and weak in body, he soon broke down, and died in 1802, at the
age of thirty-six, leaving his children penniless. The Managers so far
bettered the condition of the poor as to subscribe, on behalf of the
Institution, £50 towards the publication of his posthumous work on the
“Laws of Animal Life,” and to allow the book to be dedicated to them.

The accompanying illustration (p. 70), from a drawing by Gillray,
entitled “Pneumatic Experiments at the Royal Institution,” shows the
theatre during a lecture by Garnett, with Davy acting as assistant. Sir
John Hippesley is represented as breathing the “pleasure-giving air.”
The standing figure near the door is Rumford, and among the audience
are Isaac Disraeli, Lord Stanhope, Earl Pomfret, and Sir H. Englefield.

Accounts differ as to the precise means by which Davy was brought to
the notice of Count Rumford, nor is it very important to know whether
it was through the intervention of Davies Gilbert, or Dr. Hope, or Mr.
Underwood, or, as was most probably the case, of all three.

In a letter to Hope now before me Davy writes:--

    “I believe it is in a great measure owing to your kind mention
    of me to Count Rumford, that I occupy my present situation in
    the Royal Institution. I ought to be very thankful to you; for
    most of my wishes through life are accomplished, as I am enabled
    to pursue my favourite study, and at the same time to be of some
    little utility to Society.”

[Illustration: PNEUMATIC EXPERIMENT AT THE ROYAL INSTITUTION. (_After
Gillray._)]

This much, at least, is certain: there was an absolute agreement among
those who had the best means of judging that no better appointment
was possible. And yet, if we are to credit Dr. Paris, the first
impression produced on Rumford by Davy’s personal appearance was
highly unfavourable, and the Count would not allow him to lecture in
the theatre until he had given a specimen of his abilities in the
smaller lecture-room, which old _habitués_ of the Royal Institution
well remember. Dr. Paris adds that his first lecture entirely removed
every prejudice, and at its conclusion Rumford exclaimed, “Let him
command any arrangements which the Institution can afford.” And he was
accordingly on the next day promoted to the theatre.

Six weeks after his arrival, he gave his first public lecture. How he
acquitted himself, may be gleaned from the following account, given
under the heading of the “Royal Institution of Great Britain” in the
_Philosophical Magazine_, vol. x., p. 281 (1801):--

    “It must give pleasure to our readers to learn that this new and
    useful institution, the object of which is the application of
    science to the common purposes of life, may be now considered as
    settled on a firm basis....

    “We have also to notice a course of lectures, just commenced
    at the institution, on a new branch of philosophy--we mean the
    Galvanic Phenomena. On this interesting branch Mr. Davy (late
    of Bristol) gave the first lecture on the 25th of April. He
    began with the history of Galvanism, detailed the successive
    discoveries, and described the different methods of accumulating
    galvanic influence.... He showed the effects of galvanism on the
    legs of frogs, and exhibited some interesting experiments on the
    galvanic effects on the solutions of metals in acids....

    “Sir Joseph Banks, Count Rumford, and other distinguished
    philosophers were present. The audience were highly gratified,
    and testified their satisfaction by general applause. Mr. Davy,
    who appears to be very young, acquitted himself admirably well;
    from the sparkling intelligence of his eye, his animated manner,
    and the _tout ensemble_, we have no doubt of his attaining a
    distinguished eminence.”

The Managers were so far satisfied, that at a meeting held on June 1st
they passed the following resolutions:--

    “Resolved--That Mr. Humphry Davy, Director of the Chemical
    Laboratory, and Assistant Lecturer in Chemistry, has, since he
    has been employed at the Institution, given satisfactory proofs
    of his talents as a Lecturer.”

    “Resolved--That he be appointed, and in future denominated,
    Lecturer in Chemistry at the Royal Institution, instead of
    continuing to occupy the place of Assistant Lecturer, which he
    has hitherto filled.”

In the following July, Dr. Young (“Phenomenon Young,” as he was called
at Cambridge), the great exponent of the Undulatory Theory of Light,
was engaged as Professor of Natural Philosophy, Editor of the Journals,
and General Superintendent of the House.[D]

    [D] Young’s connection with the Royal Institution was
        comparatively brief. On July 4th, 1803, it was resolved
        “That Dr. Young be paid the balance of two years’ complete
        salary, and that his engagement with the Institution
        terminate from this time.”

At a meeting held in the same month, the Managers

    “Resolved--That a Course of Lectures on the Chemical Principles
    of the Art of Tanning be given by Mr. Davy. To commence the
    second of November next; and that respectable persons of
    the trade, who shall be recommended by Proprietors of the
    Institution, be admitted to these lectures gratis.”

To order a young man of twenty-two, who had probably never seen the
inside of tannery, to give an account of the art and mystery of
leather-making, would seem to savour somewhat of what Coleridge would
style “_ultra-crepidation_,” and accordingly the Managers further

    “Resolved--That Mr. Davy have permission to absent
    himself--during the months of July, August, and September for
    the purpose of making himself more particularly acquainted
    with the practical part of the business of tanning, in order
    to prepare himself for giving the above-mentioned course of
    lectures.”

Lectures on “The Chemical Principles of the Process of Tanning
Leather, and of the objects that must particularly be had in view in
attempts to improve that most useful art” are mentioned in Rumford’s
first prospectus, and the foregoing resolutions were probably passed
in consequence. Davy did a considerable amount of experimental work
in connection with these lectures, and the Journal of the Royal
Institution contains several short communications from him on the
chemistry of the subject, but the main facts he discovered are
contained in a memoir read to the Royal Society on February 24th,
1803, and published in the _Philosophical Transactions_ of that year,
under the title of an “Account of Some Experiments and Observations on
the constituent Parts of certain astringent Vegetables; and on their
Operation in Tanning.”

Although Davy, by his earnestness, his knowledge, his felicity of
expression, and by a certain dignity of treatment which seemed to
invest even the homeliest subjects with unlooked-for importance, could
interest an audience on almost any subject he brought before them,
we may be sure that his soul soon sighed for a loftier theme than
leather. He found it on the occasion of his lecture of January 21st,
1802, when he delivered the introductory discourse of that session. The
date, indeed, is a red-letter day not only in Davy’s history but also
in that of the Royal Institution. From that time the position of the
Institution in the scientific and social world of London would seem to
be assured.

Its affairs up to this time had been gradually going from bad to worse.
The enthusiasm with which it was started a couple of years back had
apparently spent itself, and Rumford, by his _hauteur_ and high-handed
management, had alienated many powerful friends. The subscriptions,
which in 1800 had reached £11,047, had fallen in 1802 to £2,999, whilst
the expenses were annually increasing. The outlook was gloomy in the
extreme, and everything seemed to portend that the latest scheme for
the amelioration of humanity was about to share the too common fate of
such projects. The young man of twenty-three, however, changed all this
as if by the stroke of a magician’s wand. No Prince Fortunatus could
have done more.

His theme was not too ambitious; it would be considered even trite
and commonplace to-day, and the man would be very bold or very simple
who would now attempt to deal with it in the theatre of the Royal
Institution; for this introductory lecture was nothing more than an
exordium on the worth of science as an agent in the improvement of
society. It was, and was felt to be, however, an _apologia_ for the
very existence of the Institution. Rumford and his fellow managers
would seem to have staked everything on a single throw. Davy’s power as
a lecturer had been noised abroad, and we may be sure that Coleridge
and his other friends did not keep their tongues still. Coleridge,
indeed, told the literary world that he assiduously attended Davy’s
lectures, to increase his stock of metaphors. The youth who had
discovered “the pleasure-producing air” was talked about in fashionable
circles; and Mr. Bernard and the Count used their persuasiveness, and
Sir Joseph Banks his social power, to secure for him the most cultured
audience in London. If we may credit Dr. Paris, other influences, too,
were at work. Davy’s association with Beddoes had probably gained for
him the goodwill of the Tepidarians, even if it did not actually
give him the _entrée_ to the Society; and these Red Republicans,
whose “pious orgies” at Old Slaughter’s Coffee-House in St. Martin’s
Lane consisted mainly in libations of tea, vied with the Royalists in
their efforts to pave his triumphal way. His success was instant and
complete. In a series of lofty and impassioned periods he traced the
services of science to humanity; he dwelt upon its dignity and nobility
as a pursuit, upon its value as a moral and educational force. The
small, spare youth, with his earnestness, his eloquence, his unaffected
manner, the play of his mobile features, his speaking eyes--“eyes
which,” as one of his fair auditors was heard to remark, “were made for
something besides poring over crucibles”--held his hearers spellbound
as he declaimed such sentences as these:--

    “Individuals influenced by interested motives or false views may
    check for a time the progress of knowledge;--moral causes may
    produce a momentary slumber of the public spirit;--the adoption
    of wild and dangerous theories, by ambitious or deluded men, may
    throw a temporary opprobrium on literature; but the influence of
    true philosophy will never be despised; the germs of improvement
    are sown in minds, even where they are not perceived; and
    sooner or later the springtime of their growth must arrive. In
    reasoning concerning the future hopes of the human species, we
    may look forward with confidence to a state of society, in which
    the different orders and classes of men will contribute more
    effectually to the support of each other than they have hitherto
    done. This state, indeed, seems to be approaching fast; for, in
    consequence of the multiplication of the means of instruction
    the man of science and the manufacturer are daily becoming more
    assimilated to each other. The artist, who formerly affected
    to despise scientific principles, because he was incapable of
    perceiving the advantages of them, is now so far enlightened as
    to favour the adoption of new processes in his art, whenever
    they are evidently connected with the diminution of labour;
    and the increase of projectors, even to too great an extent,
    demonstrates the enthusiasm of the public mind in its search
    after improvement....

    “The unequal division of property and of labour, the differences
    of rank and condition amongst mankind, are the sources of power
    in civilised life--its moving causes, and even its very soul.
    In considering and hoping that the human species is capable of
    becoming more enlightened and more happy, we can only expect
    that the different parts of the great whole of society should be
    intimately united together, by means of knowledge and the useful
    arts; that they should act as the children of one great parent,
    with one determinate end, so that no power may be rendered
    useless--no exertions thrown away.

    “In this view, we do not look to distant ages, or amuse ourselves
    with brilliant though delusive dreams, concerning the infinite
    improveability of man, the annihilation of labour, disease,
    and even death, but we reason by analogy from simple facts, we
    consider only a state of human progression arising out of its
    present condition,--we look for a time that we may reasonably
    expect--FOR A BRIGHT DAY, OF WHICH WE ALREADY BEHOLD THE DAWN.”

Those who may read these sentences will either smile at their seeming
archaism, or wonder at the antiquity of their argument; for the lesson
which Davy inculcated at the beginning of the century is still at its
close dinned into our ears, and practically all the stock reasons urged
by latter-day writers and platform speakers on technical education and
the abstract value of science are to be found in his lectures. But the
circumstances of 1802 were widely different from those of 1896. The
birth of the century was a singularly auspicious time for science; and
many cultured men who knew nothing of science, yet felt in a dim sort
of way that it was destined to be a mighty factor in civilisation.
Davy’s words struck a sympathetic chord; they served to formulate and
define ideas of which all who lived in the spirit of the times and
shared in its movement must have been conscious. Speaking to willing
and receptive ears, and with every attribute of manner, speech,
and interest in his favour, he saw his chance: and with a practical
sagacity beyond his years, he seized it.

Davy’s triumph is recorded in many contemporary notices, and it lives
as one of the traditions of the Royal Institution.

Francis Horner thus records his impressions in his journal, under date
March 31st, 1802:--

    “I have been once to the Royal Institution and heard Davy
    lecture to a mixed and large assembly of both sexes, to the
    number perhaps of three hundred or more. It is a curious scene;
    the reflections it excites are of an ambiguous nature, for the
    prospect of possible good is mingled with the observation of
    much actual folly. The audience is assembled by the influence of
    fashion merely; and fashion and chemistry form a very incongruous
    union....

    “Davy’s style of lecturing is much in favour of himself, though
    not, perhaps, entirely suited to the place; it has rather a
    little awkwardness, but it is that air which bespeaks real
    modesty and good sense; he is only awkward because he cannot
    condescend to assume that theatrical quackery of manner which
    might have a more imposing effect. This was my impression from
    his lecture. I have since (April 2nd) met Davy in company, and
    was much pleased with him; a great softness and propriety of
    manner, which might be cultivated into elegance; his physiognomy
    struck me as being superior to what the science of chemistry, on
    its present plan, can afford exercise for; I fancied to discover
    in it the lineaments of poetical feeling.” (“Memoirs of Horner,”
    vol. i., p. 182.)

Davy’s friend Purkis has left us the following still more glowing
account:--

    “The sensation created by his first [second] course of Lectures
    at the Institution, and the enthusiastic admiration which they
    obtained, is at this period scarcely to be imagined. Men of the
    first rank and talent,--the literary and the scientific, the
    practical and the theoretical, blue stockings, and women of
    fashion, the old and the young, all crowded--eagerly crowded
    the lecture-room. His youth, his simplicity, his natural
    eloquence, his chemical knowledge, his happy illustrations, and
    well-conducted experiments, excited universal attention and
    unbounded applause. Compliments, invitations, and presents were
    showered upon him in abundance from all quarters; his society was
    courted by all, and all appeared proud of his acquaintance.... A
    talented lady, since well-known in the literary world, addressed
    him anonymously in a poem of considerable length, replete with
    delicate panegyric and genuine feeling.... It was accompanied
    with a handsome ornamental appendage for the watch, which he
    was requested to wear when he delivered his next lecture, as a
    token of having received the poem and pardoned the freedom of the
    writer.”

The anonymous poem “replete with delicate panegyric and genuine
feeling” is before me as I write. It is signed “Fidelissima,” and
is one of several which the same talented lady addressed to him at
different times, and which were found among his papers at his death.
Some of them, as sonnets, are of considerable merit, and, had space
permitted, are well worthy of reproduction.

The Tepidarians--again on the authority of Dr. Paris--were delighted.
Sanguine in the success of their child--for so they considered
Davy--they purposely appointed their anniversary festival on the day of
his anticipated triumph. Their dinner was marked by every demonstration
of hilarity, and the day was ended by a masquerade at Ranelagh.

Dr. John Davy, it should be said, rather sniffs at the Tepidarians and
their “ultra-principles,” and doubts if his brother ever belonged to
their society. Be this as it may, it is certain that the “Royalists”
and the fashionable world into which he was drawn soon influenced
Davy’s social and political views. Dr. Davy, whilst willing enough to
appreciate at their proper value his brother’s natural and intellectual
advantages as contributing to his success, points out that other
circumstances connected with the Institution and the period conspired
to help him:--

    “The Royal Institution was a new experiment. Novelty in itself
    is delightful, especially to people of rank and fortune, who at
    that time in consequence of the Continent being closed, and owing
    to the war, must have been delighted to have had opened to them
    a new and unexpected source of interest, fitted to amuse those
    who were suffering from _ennui_, and to instruct those who were
    anxious for instruction. The Royal Institution, moreover, was the
    creation of a large number of influential persons, both in the
    higher ranks of society and of science. This alone might have
    sufficed to render it fashionable, and, if fashionable, popular.
    The period, morally and politically considered, aided the effect;
    a time of great political excitement had just terminated; a time
    of gloom and despondency was then commencing. Whatever diverted
    the public mind and afforded new objects of contemplation, pure
    and independent sources of amusement and gratification, must
    have been very welcome to all reflecting persons, even without
    taking into account the possible and probable good which might be
    conferred by the Institution on society, in accordance with the
    intentions with which it was first established.”

Davy thus expressed his own feeling of satisfaction to his mother:--

            “London.

    “MY DEAR MOTHER,--I have been very busy in the preparation for
    my lectures; and for this reason I have not written to you. I
    delivered my second lecture to-day, and was very much flattered
    to find the theatre overflowing at this, as well as at the first.
    I am almost surprised at the interest taken by so many people of
    rank, in the progress of chemical philosophy; and I hope I am
    doing a great deal of good, in being the means of producing and
    directing the taste for it.

    “I have been perfectly well since I visited Cornwall; and I enter
    upon my campaign in high health and spirits. After four months of
    hard but pleasant labour, I shall again be free!

    “I hope you are all well. I very often reflect upon the times
    that are past; and my mind is always filled with gratitude to the
    Supreme Being, who has made us all happy; and that, in placing us
    in distant parts, and in different circles, neither our feelings
    or affections have been disturbed....

    “I shall be very glad to see you again. I intend in June to pass
    through Scotland and to visit the Western Isles; but I hope I
    shall spend a part of the autumn with you.

    “Pray write to me and give me a little news. Beg Kitty and Grace
    and Betsy and John to recollect me.

            “I am, my dear mother, your very affectionate son
                                                     “H. DAVY.”

The interest and spirit of enthusiasm thus roused was sedulously
cultivated by Davy, and turned to the purposes of the Institution which
he served. Rumford was no longer its moving and controlling spirit:
his duty to the Elector of Bavaria, and his ill-starred devotion to
Madame Lavoisier, had gradually drawn him away from London, and in 1803
he ceased to take any active part in the fortunes of his offspring.
Shortly afterwards Sir Joseph Banks also withdrew. In a letter written
April, 1804, he tells Rumford that his continued absence from England
is a great detriment to the Institution:--

    “It is now entirely in the hands of the profane. I have declared
    my dissatisfaction at the mode in which it is carried on, and my
    resolution not to attend in future. Had my health and spirits not
    failed me, I could have kept matters in their proper level, but
    sick, alone, and unsupported, I have given up what cannot now
    easily be recovered.”

Sir John Hippesley, who became treasurer, strove to make the
Institution above all things fashionable. He had a project for placing
private boxes in the theatre, and was concerned about its want of a
proper coat-of-arms. Mr. Bernard still continued to hope that Sydney
Smith’s lectures on Moral Philosophy might somehow better the condition
of the poor. They would, at least, said Horner, “make the real
blue-stockings a little more disagreeable than ever, and sensible women
a little more sensible.” But the real directing power was Davy, and
he gradually stamped upon the place the character it now possesses.
How he felt his power and used it, may be gleaned from the following
extract from a lecture in 1809, in reference to a fund which had been
raised to supply him with a great voltaic battery:--

    “In a great country like this, it was to be expected that a
    fund could not long be wanting for pursuing or perfecting any
    great scientific object. But the promptitude with which the
    subscription filled was so great, as to leave no opportunity to
    many zealous patrons of science for showing their liberality. The
    munificence of a few individuals has afforded means more ample
    and magnificent than those furnished by the Government of a rival
    nation; and I believe we have preceded them in the application of
    the means. In this kind of emulation, our superiority, I trust,
    will never be lost; and I trust that the activity belonging to
    our sciences will always flow from the voluntary efforts of
    individuals, from whom the support will be an honour--to whom it
    will be honourable....

    “Without facilities for pursuing his object, the greatest genius
    in experimental research may live and die useless and unknown.
    Talents of this kind cannot, like talents for literature and
    the fine arts, call forth attention and respect. They can
    neither give popularity to the names of patrons, nor ornament
    their houses. They are limited in their effects, which are
    directed towards the immutable interests of society. They
    cannot be made subservient to fashion or caprice; they must
    forever be attached to truth, and belong to nature. If we merely
    consider _instruction_ in physical science, this even requires
    an expensive apparatus to be efficient; for without proper
    ocular demonstrations, all lectures must be unavailing,--things
    rather than words should be made the objects of study. A
    certain knowledge of the beings and substances surrounding us
    must be felt as a want by every cultivated mind. It is a want
    which no activity of thought, no books, no course of reading
    or conversation, can supply. That a spirit for promoting
    experimental science is not wanting in the country, is proved
    by the statement which I have just made, by the foundation in
    which I have the honour of addressing you, and by the number of
    institutions rising in different parts of the metropolis and in
    the provinces. But it is clear that this laudable spirit may
    produce little effect from want of just direction. To divide and
    to separate the sources of scientific interest, is to destroy
    all their just effect. To attempt, with insufficient means, to
    support philosophy, is merely to humiliate her and render her an
    object of dirision. Those who establish foundations for teaching
    the sciences ought, at least, to understand their dignity. To
    connect pecuniary speculation, or commercial advantages, with
    schemes for promoting the progress of knowledge, is to take
    crops without employing manure; is to create sterility, and to
    destroy improvement. A scientific institution ought no more to
    be made an object of profit than an hospitable, or a charitable
    establishment. Intellectual wants are at least as worthy of
    support as corporeal wants, and they ought to be provided for
    with the same feeling of nobleness and liberality. The language
    expected by the members of a scientific body from the directors
    ought not to be, ‘We have increased your property, we have raised
    the value of your shares.’ It ought rather to be, ‘We have
    endeavoured to apply your funds to useful purposes, to promote
    the diffusion of science, to encourage discovery, and to exalt
    the scientific glory of your country.’

    “What this institution has done, it would ill become a person
    in my place to detail; but that it has tended to the progress
    of knowledge and invention, will not, I believe, be questioned.
    Compare the expenditure with the advantages. It would not support
    the least of your public amusements; and the income of an
    establishment, which, in its effects, may be said to be national,
    is derived from annual subscriptions scarcely greater than those
    which a learned professor of Edinburgh obtains from a single
    class....

    “The progression of physical science is much more connected with
    your prosperity than is usually imagined. You owe to experimental
    philosophy some of the most important and peculiar of your
    advantages. It is not by foreign conquests chiefly that you are
    become great, but by a conquest of nature in your own country.
    It is not so much by colonization that you have attained your
    preeminence or wealth, but by the cultivation of the riches
    of your own soil. Why, at this moment, are you able to supply
    the world with a thousand articles of iron and steel necessary
    for the purposes of life? It is by arts derived from chemistry
    and mechanics, and founded purely upon experiments. Why is the
    steam engine now carrying on operations which formerly employed,
    in painful and humiliating labour, thousands of our robust
    peasantry, who are now more nobly or more usefully serving
    their country either with the sword or with the plough? It was
    in consequence of experiments upon the nature of heat and pure
    physical investigations.

    “In every part of the world manufactures made from the mere
    clay and pebbles of your soil may be found; and to what is this
    owing? To chemical arts and experiments. You have excelled all
    other people in the products of industry. But why? Because you
    have assisted industry by science. Do not regard as indifferent
    what is your true and greatest glory. Except in these respects,
    and in the light of a pure system of faith, in what are you
    superior to Athens or to Rome? Do you carry away from them the
    palm in literature and the fine arts? Do you not rather glory,
    and justly too, in being, in these respects, their imitators?
    Is it not demonstrated by the nature of your system of public
    education, and by your popular amusements? In what, then, are you
    their superiors? In every thing connected with physical science;
    with the experimental arts. These are your characteristics. Do
    not neglect them. You have a Newton, who is the glory, not only
    of your own country, but of the human race. You have a Bacon,
    whose precepts may still be attended to with advantage. Shall
    Englishmen slumber in that path which these great men have
    opened, and be overtaken by their neighbours? Say, rather, that
    all assistance shall be given to their efforts; that they shall
    be attended to, encouraged, and supported.”

On a subsequent occasion, when the subjugation of Europe was threatened
by the restless military spirit of France, he thus dilated upon the
influence of experimental philosophy in strengthening the desire for
rational freedom:--

    “The scientific glory of a country may be considered, in some
    measure, as an indication of its innate strength. The exaltation
    of reason must necessarily be connected with the exaltation of
    the other noble faculties of the mind; and there is one spirit of
    enterprise, vigour, and conquest, in science, arts, and arms.

    “Science for its progression requires patronage,--but it must
    be a patronage bestowed, a patronage received, with dignity.
    It must be preserved independent. It can bear no fetters, not
    even fetters of gold, and least of all those fetters in which
    ignorance or selfishness may attempt to shackle it.

    “And there is no country which ought so much to glory in its
    progress, which is so much interested in its success, as this
    happy island. Science has been a prime cause of creating for us
    the inexhaustible wealth of manufactures, and it is by science
    that it must be preserved and extended. We are interested as a
    commercial people,--we are interested as a free people. The age
    of glory of a nation is likewise the age of its security. The
    same dignified feeling, which urges men to endeavour to gain a
    dominion over nature, will preserve them from the humiliation of
    slavery. Natural, and moral, and religious knowledge, are of one
    family; and happy is that country, and great its strength, where
    they dwell together in union.”

It was, of course, to be expected that amidst the general chorus of
approval some discordant notes should be heard. People who preferred
the severe and formal manner of his colleague, Dr. Young, who, in spite
of his profound knowledge, could never keep an audience together, said
that Davy’s style was too florid and imaginative; that his imagery
was inappropriate, and his conceits violent; that he was affected and
swayed by a mawkish sensibility. Dr. Paris would have us believe there
was some show of justice in this accusation, but he thinks that “the
style which cannot be tolerated in a philosophical essay may under
peculiar circumstances be not only admissible but even expedient in a
popular lecture.” The “peculiar circumstance” in Davy’s case was, in
Dr. Paris’s opinion, the Royal Institution audience.

    “Let us consider for a moment,” he says, “the class of persons
    to whom Davy addressed himself. Were they students prepared to
    toil with systematic precision, in order to obtain knowledge as
    a matter of necessity?--No--they were composed of the gay and
    the idle, who could only be tempted to admit instruction by the
    prospect of receiving pleasure,--they were children, who could
    only be induced to swallow the salutary draught by the honey
    around the rim of the cup.”

That Davy himself was not wholly unconscious of this fact may be
gathered from a letter which he wrote to Mr. Davies Gilbert at about
this time. He says:--

    “My labours in the Theatre of the Royal Institution have been
    more successful than I could have hoped from the nature of them.
    In lectures, the effect produced upon the mind is generally
    transitory; for the most part, they amuse rather than instruct,
    and stimulate to enquiry rather than give information. My
    audience has often amounted to four and five hundred, and
    upwards; and amongst them some promise to become permanently
    attached to chemistry. This science is much the fashion of the
    day.”

Whatever may be urged against Davy’s style of lecturing, his purely
scientific memoirs are unquestionably models of their kind. His
language is so simple, and his mode of expression so uniformly clear,
and so free from technicality, that even an ordinary reader can follow
them with delight. In this respect he was consistently faithful to the
direction he gives in his “Last Days”:--

    “In detailing the results of experiments, and in giving them to
    the world, the chemical philosopher should adopt the simplest
    style and manner; he will avoid all ornaments, as something
    injurious to his subject, and should bear in mind the saying of
    the first King of Great Britain, respecting a sermon which was
    excellent in doctrine, but overcharged with poetical allusions
    and figurative language,--‘that the tropes and metaphors of the
    speaker were like the brilliant wild flowers in a field of corn,
    very pretty, but which did very much hurt the corn.’”

Dr. Paris’s remarks concerning Davy’s personal manner and his style of
lecturing were warmly controverted at the time of their publication
by several of Davy’s friends. Dr. John Davy’s account is so clear and
explicit, and so obviously based upon personal observation, for which
he had ample opportunities, that, even after making every allowance
for brotherly bias, we prefer to regard it as giving a more just
impression of Davy’s bearing in the lecture-theatre, and of the care
and pains he took to ensure success.

    “He was,” says Dr. Davy, “always in earnest; and when he amused
    most, amusement appeared most foreign to his object. His great
    and first object was to instruct, and, in conjunction with
    this, maintain the importance and dignity of science; indeed
    the latter, and the kindling a taste for scientific pursuits,
    might rather be considered his main object, and the conveying
    instruction a secondary one.”

His lecture was almost invariably written expressly for the occasion,
and usually on the day before he delivered it.

    “On this day he generally dined in his own room, and made a light
    meal on fish. He was always master of his subject; and composed
    with great rapidity, and with a security of his powers never
    failing him.... It was almost an invariable rule with him, the
    evening before, to rehearse his lecture in the presence of his
    assistants, the preparations having been made and everything in
    readiness for the experiments; and this he did, not only with
    a view to the success of the experiments, and the dexterity of
    his assistants, but also in regard to his own discourse, the
    effect of which, he knew, depended upon the manner in which it
    was delivered. He used, I remember, at this recital, to mark the
    words which required emphasis and study the effect of intonation;
    often repeating a passage two or three different times, to
    witness the difference of effect of variations in the voice. His
    manner was perfectly natural, animated and energetic, but not in
    the least theatrical. In speaking, he never seemed to consider
    himself as an object of attention; he spoke as if devoted to his
    subject, and as if his audience were equally devoted to it and
    their interest concentrated in it. The impressiveness of his
    oratory was one of its great charms ... and his eloquence,--the
    declamation, as it might be called by some, in which he indulged
    on the beauty and order of Nature ... was so well received
    because it was not affected; merely his own strong impressions
    and feelings embodied in words, and delivered with an earnestness
    which marked their sincerity.”

It must, however, be admitted that this extraordinary success was not
without its evil influence on Davy’s moral qualities. Considering his
age, and his temperament, his ambition and love of applause, he would
have been something more than human if he could have remained wholly
unaffected by the conditions in which he was placed. “The bloom of
his simplicity was dulled by the breath of adulation.” He assumed
the garb and the airs of a man of fashion, and courted the society
of the rich and the aristocratic. Time which would have been more
profitably spent in the study, or in the society of his intellectual
fellows, was frittered away in the frivolities of London society, or
in the _salons_, or at the _soirées_ of leaders of the “smart” people
of the period. The peculiar circumstances of the Royal Institution,
and the necessity for the continued adhesion to it of persons of rank
and wealth, may to some extent have led him away from the quieter and
serener joys of the philosophic life.

    “In the morning,” says Paris, “he was the sage interpreter of
    Nature’s laws; in the evening, he sparkled in the galaxy of
    fashion; and not the least extraordinary point in the character
    of this great man, was the facility with which he could cast
    aside the cares of study, and enter into the trifling amusements
    of society.--‘_Ne otium quidem otiosum_,’ was the exclamation
    of Cicero; and it will generally apply to the leisure of men
    actively engaged in the pursuits of science; but Davy, in closing
    the door of his laboratory, opened the temple of pleasure.... In
    ordinary cases, the genius of evening dissipation is an arrant
    Penelope; but Davy, on returning to his morning labours, never
    found that the thread had been unspun during the interruption.”

The following letter from Coleridge will serve to show how this change
was foreseen and deplored by his truest friends:--

            “Nether Stowey, _Feby. 17, 1803_.

    “MY DEAR PURKIS, ... I have been here nearly a fortnight; and in
    better health than usual. Tranquillity, warm rooms and a dear old
    friend, are specifics for my complaints. Poole is indeed a very,
    very good man. I like even his incorrigibility in small faults
    and deficiencies; it looks like a wise determination of Nature to
    let well alone; and is a consequence, a necessary one perhaps, of
    his immutability in his important good qualities....

    “I rejoice in Davy’s progress. There are three suns recorded
    in Scripture:--Joshua’s, that stood still; Hezekiah’s, that
    went backward; and David’s that went forth, and hastened on his
    course, like a bridegroom from his chamber. May our friend’s
    prove the latter! It is a melancholy thing to see a man, like
    the Sun in the close of the Lapland summer, meridional in his
    horizon; or like wheat in a rainy season, that shoots up well in
    the stalk, but does not _kern_. As I have hoped, and do hope,
    more proudly of Davy than of any other man; and as he has been
    endeared to me more than any other man, by the being a Thing
    of Hope to me (more, far more than my self to my own self in
    my most genial moments,)--so of course my disappointment would
    be proportionally severe. It were falsehood, if I said that I
    think his present situation most calculated, of all others, to
    foster either his genius, or the clearness and incorruptness
    of his opinions and moral feelings. I see two Serpents at the
    cradle of his genius: Dissipation with a perpetual increase
    of acquaintances, and the constant presence of Inferiors and
    Devotees, with that too great facility of attaining admiration
    which degrades Ambition into Vanity--but the Hercules will
    strangle both the reptile monsters. I have thought it possible
    to exert talents with perseverance, and to attain true greatness
    wholly pure, even from the impulses; but on this subject Davy and
    I always differed.... Yours sincerely

            “S. T. COLERIDGE.”

It would seem that Coleridge’s doubts and fears were shared also by
his host, and were communicated by him to the object of them. This, at
least, may be inferred from the following extract from a letter from
Davy to Poole:--

            “London, _May 1, 1803_.

    “MY DEAR POOLE, ... Be not alarmed, my dear friend, as to the
    effect of worldly society on my mind. The age of danger has
    passed away. There are in the intellectual being of all men,
    permanent elements, certain habits and passions that cannot
    change. I am a lover of Nature, with an ungratified imagination.
    I shall continue to search for untasted charms--for hidden
    beauties.

    “My _real_, my _waking_ existence is amongst the objects of
    scientific research: common amusements and enjoyments are
    necessary to me only as dreams, to interrupt the flow of thoughts
    too nearly analogous to enlighten and to vivify.

    “Coleridge has left London for Keswick; during his stay in
    town, I saw him seldomer than usual; when I did see him, it was
    generally in the midst of large companies, where he is the image
    of power and activity. His eloquence is unimpaired; perhaps it
    is softer and stronger. His will is probably less than ever
    commensurate with his ability. Brilliant images of greatness
    float upon his mind: like the images of the morning clouds
    upon the waters, their forms are changed by the motion of the
    waves, they are agitated by every breeze, and modified by every
    sunbeam. He talked in the course of one hour, of beginning three
    works, and he recited the poem of Christabel unfinished, and as
    I had before heard it. What talent does he not waste in forming
    visions, sublime, but unconnected with the real world! I have
    looked to his efforts, as to the efforts of a creating being; but
    as yet, he has not even laid the foundation for the new world of
    intellectual form....

            “Your affectionate friend
                        “HUMPHRY DAVY.”

Space will not permit of any more detailed account of Davy’s career
as a lecturer at the Royal Institution. During the twelve years he
occupied its Chair of Chemistry he held undisputed sway as the greatest
living expositor of chemical doctrine, and session after session saw
the theatre crowded with eager and expectant audiences.

This continued and increasing success was due not merely to his art and
skill as a speaker, but to the remarkable and astonishing character of
what he had to tell--of work which made the laboratory of the Royal
Institution even more famous than its lecture-rooms.




CHAPTER V.

THE CHEMICAL LABORATORY OF THE ROYAL INSTITUTION.


The chemical laboratory of the Royal Institution, as the scene of
Davy’s greatest discoveries--discoveries which mark epochs in the
development of natural knowledge--will for ever be hallowed ground
to the philosopher. The votaries of Hermes have raised far more
stately temples: to-day they follow their pursuit in edifices which
in architectural elegance and in equipment are palaces compared with
the subterranean structure which lies behind the Corinthian façade in
Albemarle Street. But to the chemist this spot is what the Ka’ba at
Mecca is to the follower of Mohammed, or what Iona was to Dr. Johnson:
and, if we may venture to adapt the language of the English moralist,
that student has little to be envied whose enthusiasm would not grow
warmer or whose devotion would not gain force within the place made
sacred by the genius and labours of Davy and Faraday.

And yet, were these great men to revisit the scene of their triumphs,
they would hardly recognise it, so completely altered is it by
adaptations and rearrangements rendered necessary by their discoveries.
How it appeared in their own time may be seen from the illustration on
page 91, taken from a water-colour drawing by Miss Harriet Moore, in
the possession of the Managers of the Royal Institution.

[Illustration: CHEMICAL LABORATORY OF THE ROYAL INSTITUTION IN DAVY’S
TIME.]

The first year of the century is memorable for the invention of the
voltaic pile, and for the discovery, by Nicholson and Carlisle, on
April 30th, 1800, of the electrolytic decomposition of water. As Davy
said, “the voltaic battery was an alarm-bell to experimenters in every
part of Europe; and it served no less for demonstrating new properties
in electricity, and for establishing the laws of this science, than as
an instrument of discovery in other branches of knowledge; exhibiting
relations between subjects before apparently without connection, and
serving as a bond of unity between chemical and physical philosophy.”
The capital discovery of Volta was made known in England at the
earliest possible moment through the mediation of Sir Joseph Banks, and
the study of voltaic electricity, its effects and applications, was
immediately afterwards entered upon by many Englishmen of science with
great zeal and ardour. Davy at this time had just completed his work
on Nitrous Oxide; and, powerfully impressed with the significance of
Nicholson and Carlisle’s observation, he at once turned his attention
to the subject, and even before leaving Bristol he had sent a number of
short papers on what was then usually termed the galvanic electricity
to Nicholson’s Journal. He showed that oxygen and hydrogen were
evolved from separate portions of water, though vegetable and even
animal substances intervened; and conceiving that all decomposition
might be polar, he “electrised” different compounds at the different
extremities, and found that sulphur and metallic substances appeared
at the negative pole, and oxygen and nitrogen at the positive pole,
though the bodies furnishing them were separate from each other. The
papers, however, are mainly remarkable for the fact that they served to
establish the intimate connection between the electrical effects and
the chemical changes going on in the pile, and for the conclusion drawn
concerning their mutual dependence. Within a few days after his removal
to the Royal Institution he resumed his inquiries, publishing his
results in a series of notices in the short-lived Journal of the Royal
Institution.

In 1801 he sent his first communication to the Royal Society, on “An
Account of some Galvanic Combinations, formed by the Arrangement of
single metallic Plates and Fluids, analogous to the new Galvanic
Apparatus of Mr. Volta.”

But at this period, and for some time afterwards, Davy was not
altogether free to develop his own ideas, as the work of the
laboratory was controlled by a committee which met, from time to
time, to deliberate and settle upon the researches which were to be
undertaken by their Professor. As we have seen, he was requested, in
the first place, to turn his attention to tanning, and to investigate
the astringent principles employed in the manufacture of leather.
Afterwards, when the Managers determined to form a mineralogical
collection, and to institute an assay office for the improvement of
mineralogy and metallurgy, he was ordered to make analyses of rocks
and minerals. And lastly, in consequence of an arrangement between
the Managers and the Board of Agriculture, effected by Arthur Young,
he was required to take up the subject of Agricultural Chemistry. To
a man of Thomas Young’s temperament the fussy activity of committees,
directed by such people as Bernard and Hippesley, would have been
resented as an irksome, if not intolerable, interference; but Davy
invariably acted as if he considered that their decisions promoted the
true interests of the Institution, and entered with ardour into each
new scheme. There was no irksomeness to him in being called upon to
change the current of his ideas, for he delighted in the opportunity
of exhibiting his versatility; and, confident in his powers, he had
the ambition to touch everything in turn, and to adorn it. That he
should have succeeded so well under such conditions is perhaps the
strongest evidence that could be adduced of the strength and elasticity
of his eager, active mind, and of his astonishing power of rapid,
well-directed work.

We have already dealt with his researches in connection with tanning.
The efforts of the Managers towards the improvement of mineralogy and
metallurgy, in spite of the generous assistance of Mr. Greville, Sir J.
St. Aubin, and Sir A. Hume, and the “activity and intelligence of Mr.
Davy,” proved abortive.

One outcome of Davy’s association with the matter may be seen in his
paper, published by the Royal Society in 1805, on “An Account of
some analytical Experiments on a mineral Production from Devonshire,
consisting principally of Alumine and Water.” The mineral referred to
was discovered by Dr. Wavel in an argillaceous slate near Barnstaple,
and hence was termed _wavellite_. Davy failed to recognise its true
nature, which was first correctly ascertained by Berzelius. A few
weeks later, he sent to the Royal Society a second paper “On a Method
of Analyzing Stones containing fixed Alkali, by Means of the Boracic
Acid.” The method, however, is of comparatively limited application,
and is seldom, if ever, now used in analysis. Determinative chemistry
was never one of Davy’s strong points, and few of his analytical
processes are now employed. Patient manipulation, and minute and
sustained attention to detail, were altogether foreign to his
disposition and habits, although he had the highest appreciation of
these qualities in men like Cavendish and Wollaston.

The lectures on agriculture however, were a great success, and brought
increased fame and no small profit to the lecturer. His association
with the Board of Agriculture developed into a permanent appointment;
for ten successive years he continued to lecture on the subject before
its members, and in 1813 he put together the results of his labours in
his well-known “Elements of Agricultural Chemistry.” In simplicity and
absence of ornament the style of these lectures is in marked contrast
to that which he usually employed at the Royal Institution. Dealing
with men to whom the matter was of paramount importance, he had no need
to stimulate their interest by the arts he employed in the theatre in
Albemarle Street. The very nature of the subject, perhaps, served to
remind him that tropes and metaphors were here as much out of place
as “the brilliant wild flowers in the field of corn--very pretty, but
which did very much hurt the corn.”

It would be impossible in the space at our disposal to attempt to give
a minute analysis of Davy’s work in connection with agriculture. Its
interest now is, for the most part, historical; what is of permanent
importance in the way of fact has long since been woven into the common
web of knowledge. Its greatest value was not in the novelty or the
abundance of its facts, but rather as a closely-reasoned exposition
of the relation of agriculture to science, and of the necessity
for applying the principles and methods of science to the art. The
philosophic breadth of his views, supported, on occasion, by apt
example and striking analogy, might be illustrated by many extracts.
This, for example, is how he speaks of the value of the scientific
method, and of chemistry, to husbandry:--

    “Nothing is more wanting in agriculture than experiments, in
    which all the circumstances are minutely and scientifically
    detailed. This art will advance with rapidity in proportion as
    it becomes exact in its methods. As in physical researches all
    the causes should be considered; a difference in the results may
    be produced, even by the fall of a half an inch of rain more or
    less in the course of a season, or a few degrees of temperature,
    or even by a slight difference in the subsoil, or in the
    inclination of the land.

    “Information collected, after views of distinct inquiry,
    would necessarily be more accurate, and more capable of being
    connected with the general principles of science; and a few
    histories of the results of truly philosophical experiments in
    agricultural chemistry would be of more value in enlightening and
    benefitting the farmer, than the greatest possible accumulation
    of imperfect trials conducted merely in the empirical spirit.
    It is no unusual occurrence, for persons who argue in favour
    of practice and experience, to condemn generally all attempts
    to improve agriculture by philosophical inquiries and chemical
    methods. That much vague speculation may be found in the works
    of those who have lightly taken up agricultural chemistry, it
    is impossible to deny. It is not uncommon to find a number of
    changes rung upon a string of technical terms, such as oxygen,
    hydrogen, carbon, and azote, as if the science depended upon
    words rather than upon things. But this is, in fact, an argument
    for the necessity of the establishment of just principles of
    chemistry on the subject. Whoever reasons upon agriculture, is
    obliged to recur to this science. He feels that it is scarcely
    possible to advance a step without it; and if he is satisfied
    with insufficient views, it is not because he prefers them
    to accurate knowledge, but, generally, because they are more
    current.... It has been said, and undoubtedly with great truth,
    that a philosophical chemist would most probably make a very
    unprofitable business of farming; and this certainly would be the
    case, if he were a mere philosophical chemist; and unless he had
    served his apprenticeship to the practice of the art, as well as
    to the theory. But there is reason to believe that he would be a
    more successful agriculturist than a person equally uninitiated
    in farming, but ignorant of chemistry altogether; his science,
    as far as it went, would be useful to him. But chemistry is not
    the only kind of knowledge required: it forms a part of the
    philosophical basis of agriculture; but it is an important part,
    and whenever applied in a proper manner must produce advantages.”

How highly these lectures were appreciated will be evident from the
terms in which they were referred to by Sir John Sinclair in his
address of 1806 to the Board. He says:--

    “In the year 1802, when my Lord Carrington was in the chair, the
    Board resolved to direct the attention of a celebrated lecturer,
    Mr. Davy, to agricultural subjects; and in the following year,
    during the presidency of Lord Sheffield, he first delivered
    to the members of this Institution, a course of lectures on
    the Chemistry of Agriculture. The plan has succeeded to the
    extent which might have been expected from the abilities of the
    gentleman engaged to carry it into effect. The lectures have
    hitherto been exclusively addressed to the members of the Board;
    but to such a degree of perfection have they arrived, that it is
    well worthy of consideration, whether they ought not to be given
    to a larger audience.”

The “degree of perfection” was in no small degree due to the amount
of experimental and observational work which Davy introduced into his
lectures. Mr. Bernard allotted him a considerable piece of ground
on his property at Roehampton for experimental purposes, and the
Duke of Bedford carried out trials for him at Woburn. He studied
from time to time all the operations of practical farming, examined
a great variety of soils, and investigated the nature and action of
manures. He was thus brought into contact with some of the largest
landowners and agriculturists of his time, and was an honoured guest
in the houses of men like Lord Sheffield, Lord Thanet, Mr. Coke of
Holkham, and others.[E] In the practical interest he thus displayed
in the most useful of all the arts he sought to emulate the example
of his illustrious prototype Lavoisier, and his work constitutes the
foundation of every treatise on the subject since the appearance, in
1840, of Liebig’s well-known book.

    [E] In the print of the “Woburn Sheep-Shearing,” Davy is
        represented as one of a group comprising Mr. Coke, Sir
        Joseph Banks, Sir John Sinclair, and Mr. Arthur Young.

Professor Warington, than whom no one is more fitted to express an
opinion, has favoured me with the following critical estimate of the
value of Davy’s work:--

    “The lectures profess to be exhaustive and thus present all that
    Davy had been able to collect on the subject of the relations of
    chemistry to agriculture during a period of at least 10 years.
    He appears to have made a careful study of the problems of
    agriculture for many years, and to be acquainted with English
    practice, and English experiments. There is but little reference
    to foreign practice, or foreign opinion, save where the work
    done has been purely chemical, as _e.g._ that of Gay Lussac, or
    Vauquelin. He approaches his subject in a thoroughly scientific
    manner, taking an independent view of each question, bringing all
    the knowledge at his disposal to bear upon it, and not hesitating
    to come to conclusions different from those usually received.
    The _great step_ taken in these lectures is the assertion
    that Agriculture must look to Natural Science, and especially
    to Chemistry, for the explanation of its problems and the
    improvement of its practice. Davy seems to have been the first,
    at least in this country, who boldly claimed for ‘Agricultural
    Chemistry’ the position of a distinct branch of science. He was
    probably the earliest example of a first-class chemist, who
    seriously and continuously devoted his best attention to the
    subject of agriculture.

    “The lectures, looked at from a modern standpoint, are of
    unequal value. The method of food-analysis is very poor, and it
    is somewhat surprising that the accurate mode of determining
    nitrogen employed by Gay Lussac is not made use of in Davy’s
    analyses. Nevertheless he manages to ascertain that spring sown
    wheat is richer in gluten than autumn sown, and the wheat of hot
    countries richer than the wheat of temperate regions, statements
    which are quite correct.

    “Lecture VI. is decidedly poor. Davy believes that plants feed
    on carbonaceous matter by their roots, and this mistaken theory
    leads him to assign an undue value to organic substances as
    manures. It seems curious nowadays to find the whole subject of
    manures treated with hardly any reference to their contents in
    nitrogen, phosphoric acid, or potash.

    “Lecture IV. is one of his best lectures, full of keen
    observation and suggestive experiment.

    “The references to his own agricultural experiments are very
    numerous; he seems to have made experiments on every subject of
    inquiry that came before him. There is however no attempt at an
    extended and thorough investigation of any subject, and for want
    of this the truth is sometimes missed. Thus in his trials of
    various ammonium salts as manures he finds the carbonate to be
    effective, the chloride to be of little value, and the sulphate
    of no good at all, whereas the last-named salt is now generally
    chosen as a manure.

    “There are some paragraphs that read like the inspirations of
    genius, though it is now of course difficult to tell to what
    extent his statements and opinions were warranted by the facts
    then known. He gives a wonderfully correct idea of the action of
    peas or beans in rotation, even including the statement that they
    obtain their nitrogen from the atmosphere.”

Although his time and energy were necessarily largely absorbed by
the demands of the Managers, Davy never lost sight of the subject
of voltaic electricity, and at intervals he was able to resume his
inquiries upon it. What specially impressed him was the power of
the voltaic pile as an analytic agent; and his laboratory journals,
preserved at the Royal Institution, record the results of numerous
trials on the behaviour of compound substances under its influence.
In spite of innumerable distractions and constant interruptions, due
mainly to the precarious position of the Institution, Davy gradually
succeeded in unravelling the fundamental laws of electro-chemistry, and
in thus importing a new order of conceptions, altogether unlooked for
and undreamt of, into science. This really constitutes his greatest
claim as a philosopher to our admiration and gratitude. The isolation
of the metals of the alkalis, and the proof of the compound nature of
the alkaline earths, were unquestionably achievements of the highest
brilliancy, and as such appeal strongly to the popular imagination.
But they were only the necessary and consequential links in a chain
of discovery which, had Davy neglected to make them, would have been
immediately forged by others. It is significant that almost immediately
after the capital discovery of Nicholson and Carlisle, Dr. Henry of
Manchester, the well-known friend and collaborator of Dalton, should
have made the attempt to separate the presumed metallic principle of
potash by the agency of voltaic electricity.

       *       *       *       *       *

Davy communicated the results of his inquiries made prior to the summer
of 1806 in a paper to the Royal Society, which was made the Bakerian
lecture of the year.[F] It is entitled “On some chemical Agencies of
Electricity,” and is divided in nine sections and an introduction.
In the first section, “On the Changes produced by Electricity in
Water,” he set at rest the disputed question as to the origin of the
acid and alkaline matter which had been observed to form during the
electrolysis of this liquid. By some these substances were supposed to
be _generated_ from pure water by the action of electricity; and M.
Brugnatelli had even attempted to prove the existence of a body _sui
generis_ which he termed the _electric acid_. By a series of convincing
experiments Davy showed that the substances were due to the presence of
saline matter in the water, derived either from faulty purification,
or from the solvent action of the water on the vessels, etc., with
which it was in contact. Cruickshank had found that in some cases the
acid was nitric acid and the alkali ammonia: these substances were
shown by Davy to be due to the presence of dissolved air. When pure
water, contained in vessels on which it exerted no solvent action,
was “electrised” _in vacuo_, not a trace of either acid or alkali was
produced.

    [F] This lecture, which is one of the events of each session
        of the Royal Society, owes its origin to Mr. Henry Baker,
        F.R.S., a learned antiquary and naturalist, who, by his
        will of July, 1763, bequeathed the sum of £100 to the
        Society, the interest of which was to be applied “for
        an oration or discourse to be spoken or read yearly by
        someone of the Fellows of that Society, on such part
        of Natural History or Experimental Philosophy, at such
        time, and in such manner, as the President and Council
        of the said Society for the time being, shall please to
        order and appoint.” Baker died in 1774, and the bequest
        came into operation during the presidency of Sir John
        Pringle; and Peter Woulfe--one of the last of the English
        alchemists--was appointed to deliver the lecture, which he
        did for three successive years.

In the second section, “On the Agencies of Electricity in the
Decomposition of various Compounds,” he begins by pointing out that in
all the experiments recorded in the preceding section--that is, in all
changes in which acid and alkaline matter had been present--the acid
matter collected in the water round the positive pole, and the alkaline
matter round the negative pole. This he shows to be true even of such
sparingly soluble substances as gypsum, the sulphates of strontium and
barium, and fluorspar. By connecting together cups or vessels made of
the substances under investigation by a thread of well-washed asbestos,
as suggested by Wollaston, he found that in all cases the acid element
collected round the positive, and the earthy base round the negative
pole. Basalt from Antrim, a zeolite from the Giant’s Causeway, vitreous
lava from Etna, and even glass, in like manner yielded alkaline matter
to water when subjected to the action of voltaic electricity. Soluble
salts, such as the sulphates of sodium, potassium, and ammonium, the
nitrates of potassium and barium, the succinate, oxalate and benzoate
of ammonium, were similarly decomposed: the acids in a certain time
collected in the tube containing the positive wire, and the alkalis and
earths in that containing the negative wire. When metallic solutions,
such as those of iron, zinc, and tin were employed, metallic crystals
or depositions were formed on the negative wire, and oxide was likewise
deposited round it; and a great excess of acid was soon found in the
opposite cup.

In the next section, “On the Transfer of Certain of the Constituent
Parts of Bodies by the Action of Electricity,” he points out that
the observations of Gautherot and of Hisinger and Berzelius rendered
it probable that the saline elements evolved in decompositions by
electricity were capable of being transferred from one electrified
surface to another, according to their usual order of arrangement, but
that exact observations on this point were wanting. He connected a cup
of gypsum with one of agate by means of asbestos, and filling each
with purified water, he inserted the negative wire of the battery in
the agate cup, and the positive wire in that of the sulphate of lime.
In about four hours he found a strong solution of lime in the agate
cup, and sulphuric acid in that of gypsum. By reversing the order, and
carrying on the process for a similar length of time, the sulphuric
acid appeared in the agate cup, and the solution of lime on the
opposite side. Many trials were made with other saline substances with
analogous results.

The time required for these transmissions (the quantity and intensity
of the electricity, and other circumstances remaining the same) seemed
to be related to the length of the intermediate column of water.

To ascertain whether the contact of the saline solution with a
metallic surface was necessary for the decomposition and transference,
he introduced purified water into two glass tubes; a vessel containing
solution of potassium chloride was connected with each of the tubes by
means of asbestos; on introducing the wires into the tubes alkaline
matter soon appeared in one tube, and acid matter in the other; and in
the course of a few hours moderately strong solutions of potash and of
hydrochloric acid were formed.

Two tubes, one containing distilled water, the other a solution of
potassium sulphate, were each connected by asbestos threads with a
vessel containing a dilute solution of litmus; the saline matter was
negatively electrified; and as it was natural to suppose that the
sulphuric acid in passing through the water to the positive side would
redden the litmus in its course, some slips of litmus paper were placed
above and below the pieces of asbestos, directly in the circuit: it
was found that the acid and alkali passed through the litmus solution
without effecting any change in colour.

    “As acid and alkaline substances during the time of their
    electrical transfer passed through water containing vegetable
    colours without affecting them, or apparently combining with
    them, it immediately became an object of inquiry whether they
    would not likewise pass through chemical menstrua having stronger
    attractions for them; and it seemed reasonable to suppose that
    the same power which destroyed elective affinity in the vicinity
    of the metallic points would likewise destroy it, or suspend its
    operation, throughout the whole of the circuit.”

To test this supposition, solution of potassium sulphate was placed
in contact with the negative wire, and pure water in contact with the
positive wire and a weak solution of ammonia was made the middle link
of the conducting chain, so that no sulphuric acid could pass to
the positive pole in the distilled water without passing through the
solution of ammonia.

In less than five minutes it was found that acid was collecting round
the positive pole, and in half an hour the water was sour to the
taste, and gave a precipitate with barium nitrate. Hydrochloric acid
from common salt, and nitric acid from nitre were transmitted through
concentrated alkaline menstrua under similar circumstances. Strontia
and baryta readily passed, like the other alkaline substances, through
hydrochloric and nitric acids; and _vice versâ_ these acids passed
with facility through aqueous solution of baryta and strontia; but it
was impossible to pass sulphuric acid through baryta or strontia, or
to pass baryta and strontia through sulphuric acid, as precipitates of
insoluble barium and strontium sulphate were formed.

       *       *       *       *       *

In the next section, “On Some General Observations on these Phenomena,
and on the Mode of Decomposition and Transition,” he summarises the
foregoing results:--

    “It will be a general expression of the facts that have been
    detailed, relating to the changes and transitions by electricity,
    in common philosophical language, to say that hydrogen, the
    alkaline substances, the metals, and certain metallic oxides,
    are attracted by negatively electrified metallic surfaces,
    and repelled by positively electrified metallic surfaces; and
    contrariwise, that oxygen and acid substances are attracted
    by positively electrified metallic surfaces, and repelled by
    negatively electrified metallic surfaces; and these attractive
    and repulsive forces are sufficiently energetic to destroy or
    suspend the usual operation of elective affinity.

    “It is very natural to suppose, that the repellent and attractive
    energies are communicated from one _particle to another particle_
    of the same kind, so as to establish a conducting chain in the
    fluid; and that the locomotion takes place in consequence;
    and that this is really the case seems to be shown by many
    facts. Thus, in all the instances in which I examined alkaline
    solutions through which acids had been transmitted, I always
    found acid in them whenever any acid matter remained at the
    original source....

    “In the cases of the separation of the constituents of water,
    and of solutions of neutral salts forming the whole of the
    chain, there may possibly be a succession of decompositions,
    and recompositions throughout the fluid. And this idea is
    strengthened by the experiments on the attempt to pass barytes
    through sulphuric acid, and muriatic acid through solution of
    sulphate of silver, in which as insoluble compounds are formed
    and carried out of the sphere of the electrical action, the power
    of transfer is destroyed.”

In the next section, “On the General Principles of the Chemical Changes
produced by Electricity,” he points out that it had been already
shown by Bennet that many bodies brought into contact and afterwards
separated exhibited _opposite_ states of electricity; and that this
observation had been confirmed and extended by Volta, who had supposed
that it also takes place with regard to metals and fluids. In his
paper in the _Philosophical Transactions_ of 1801, the first he
sent to the Royal Society, Davy had shown that when alternations of
single metallic plates and acid and alkaline solutions were employed
in the construction of voltaic combinations, the alkaline solutions
always received the electricity from the metal, and the acid always
transmitted it to the metal.

In the simplest case of electrical action, the alkali which receives
electricity from the metal would necessarily, on being separated from
it, appear positive, whilst the acid under similar circumstances would
be negative; and these bodies, having respectively with regard to the
metals that which may be called a positive and a negative electrical
energy, in their repellent and attractive functions seem to be governed
by laws the same as the common laws of electrical attraction and
repulsion.

The seventh section treats of “The Relations between the Electrical
Energies of Bodies and their Chemical Affinities”:--

    “As the chemical attraction between two bodies seems to be
    destroyed by giving one of them an electrical state different
    from that which it naturally possesses; that is, by bringing it
    artificially into a state similar to the other, so it may be
    increased by exalting its natural energy. Thus, whilst zinc, one
    of the most oxidable of the metals, is incapable of combining
    with oxygen when negatively electrified in the circuit, even by
    a feeble power; silver, one of the least oxidable, easily unites
    to it when positively electrified; and the same thing might
    be said of other metals. Amongst the substances that combine
    chemically, all those, the electrical energies of which are
    well known, exhibit opposite states; thus copper and zinc, gold
    and quicksilver, sulphur and the metals, the acid and alkaline
    substances, afford opposite instances; and supposing perfect
    freedom of motion in their particles or elementary matter,
    they ought according to the principles laid down, to attract
    each other in consequence of their electrical powers. In the
    present state of our knowledge it would be useless to attempt
    to speculate on the remote cause of the electrical energy,
    or the reason why different bodies, after being brought into
    contact should be found differently electrified; its relation to
    chemical affinity is however, sufficiently evident. May it not be
    identical with it, and an essential property of matter?”

How Davy sought to elaborate a theory of chemical affinity on these
facts will be sufficiently obvious from the following extracts:--

    “Supposing two bodies, the particles of which are in different
    electrical states, and those states sufficiently exalted to give
    them an attractive force superior to the power of aggregation,
    a combination would take place which would be more or less
    intense according as the energies were more or less perfectly
    balanced; and the change of properties would be correspondently
    proportional.”

    “When two bodies repellent of each other act upon the same
    body with different degrees of the same electrical attracting
    energy, the combination would be determined by the degree; and
    the substance possessing the weakest energy would be repelled;
    and this principle would afford an expression of the causes of
    elective affinity and the decompositions produced in consequence.”

    “Or where the bodies having different degrees of the same energy,
    with regard to the third body, had likewise different energies
    with regard to each other, there might be such a balance of
    attractive and repellent powers as to produce a triple compound;
    and by the extension of this reasoning, complicated chemical
    union may be easily explained.”

As the combined effect of many particles possessing a feeble electrical
energy may be conceived equal or even superior to the effect of a few
particles possessing a strong electrical energy, the same principle may
explain the influence of mass action, as elucidated by Berthollet.

He conceives also that it may be possible to obtain a _measure_ of
chemical affinity founded upon the energy of the voltaic apparatus
required to destroy the chemical equilibrium. He points out that, as
light and heat are the common consequences of the restoration of the
equilibrium between bodies in a high state of opposite electricities,
so it is perhaps an additional circumstance in favour of his theory
to state that heat and light are likewise the result of all intense
chemical action. And as in certain forms of the voltaic battery
when large quantities of electricity of low intensity act, heat is
produced without light; so in slow combinations there is an increase
of temperature without luminous appearance. The effect of heat in
producing combination may, he assumes, be also explained according to
these ideas. It not only gives more freedom of motion to the particles,
but in a number of cases--_e.g._ tourmaline, sulphur, etc.--it seems to
exalt the electrical energies of bodies.

In the eighth section he seeks to apply these principles to the
mode of action of the voltaic pile, and to explain the nature of
the changes which occur between the plates and the exciting fluid,
and he points out that the theory in some measure reconciles the
hypothetical principles of the action of the pile adopted by its
inventor with the opinions concerning the chemical origin of galvanism
held by the majority of British men of science at that period. At
the same time, Davy argues that the facts are in contradiction to
the assumption that chemical changes are the _primary_ causes of the
phenomena of galvanism. Moreover, in mere cases of chemical change--as
in iron burning in oxygen, the deflagration of nitre with charcoal,
the combination of potash with sulphuric acid, the amalgamation of
zinc,--electricity is never exhibited.

In the concluding section he trusts that many applications of the
general facts and principles thus indicated to the processes of
chemistry, both in art and in nature, may suggest themselves to the
philosophical inquirer. It is not improbable, he thinks, that the
electric decomposition of the neutral salts in different cases may
admit of economical uses. He is induced to hope that the new mode of
analysis may lead to the discovery of the _true_ elements of bodies:--

    “For if chemical union be of the nature which I have ventured to
    suppose, however strong the natural electrical energies of the
    elements of bodies may be, yet there is every probability of a
    limit to their strength: whereas the powers of our artificial
    instruments seem capable of indefinite increase.”

Phenomena similar to those occurring in the voltaic cell must be
produced in various parts of the interior strata of our globe, and it
is very probable that many mineral formations have been materially
influenced, or even occasioned, by such action. The electrical power
of transference may serve to explain some of the principal and most
mysterious facts in geology.

    “Natural electricity has hitherto been little investigated,
    except in the case of its evident and powerful concentration in
    the atmosphere. Its slow and silent operations in every part
    of the surface will probably be found more immediately and
    importantly connected with the order and economy of nature; and
    investigations on this subject can hardly fail to enlighten our
    philosophical systems of the earth, and may possibly place new
    powers within our reach.”

The publication of this paper exercised a profound sensation, both
at home and abroad. Berzelius, years afterwards, spoke of it as one
of the most remarkable memoirs that had ever enriched the theory of
chemistry--and the praise is the more significant when it is remembered
that Davy had thereby seemed to have taken possession of a field of
inquiry which the Swedish chemist, who was only a year younger than
Davy, had been among the first to enter. Still more significant was
the action of the French Institute. Bonaparte, when First Consul, had
announced to the Institute his intention of founding a medal “for
the best experiment which should be made in the course of each year
on the galvanic fluid,” and had further expressed his desire to give
the sum of sixty thousand francs “à celui qui, par ses expériences
et ses découvertes fera à faire à l’electricité et au galvanisme un
pas comparable à celui qu’ont fait faire à ces sciences Franklin et
Volta.” A committee of the Institute, consisting of La Place, Halle,
Coulomb, Hauy and Biot, was appointed to consider the best means of
accomplishing the wishes of the First Consul, and twelve months after
the publication of the Bakerian lecture they awarded its author the
medal. Whether the Institute had the means of awarding the sixty
thousand francs as well is more than doubtful, for it does not appear
that the sum named by Bonaparte ever went beyond the promise of it. All
that the Institute got for themselves was, as Maria Edgeworth said, “a
rating all round in imperial Billingsgate.” The two countries at this
period were at war, and the feeling of animosity was most bitter. Of
course, there were persons who said that patriotism should forbid the
acceptance of the award. Davy’s own view was more sensible and politic.
“Some people,” he said to his friend Poole, “say I ought not to accept
this prize; and there have been foolish paragraphs in the papers to
that effect; but if the two countries or governments are at war, the
men of science are not. That would, indeed, be a civil war of the worst
description: we should rather, through the instrumentality of men of
science, soften the asperities of national hostility.”




CHAPTER VI.

THE ISOLATION OF THE METALS OF THE ALKALIS.


However devoted Davy might be to scientific investigation, he was no
less mindful of the sacred claims of the long vacation. In the summer
of 1805 he went to the Lake Country, where he met Scott in company with
Wordsworth; and the occasion on which the party “climbed the dark brow
of the mighty Helvellyn,” and which gave rise to Scott’s well-known
poem, is thus referred to by Lockhart:--

    “This day they were accompanied by an illustrious philosopher
    [Davy], who was also a true poet--and might have been one of the
    greatest of poets had he chosen; and I have heard Mr. Wordsworth
    say, that it would be difficult to express the feelings with
    which he, who so often had climbed Helvellyn alone, found himself
    standing on its summit with two such men as Scott and Davy.”

But the greater part of this summer he spent in the north of Ireland,
examining the extraordinary geological features of that district. Lady
Brownrigg, the sister of the Bishop of Raphoe, has given a spirited
little account of her impressions of his appearance and manner at that
period. She was, she says, very young at the time.

    “We had been invited (I say _we_, for I was then with the Bishop
    of Raphoe) by Dr. Richardson to go to his cottage at Portrush,
    ‘to meet the famous Mr. Davy.’ We arrived a short time before
    dinner. In passing through a room we saw a youth, as he appeared,
    who had come in from fishing, and who, with a little note-book,
    was seated in a window-seat, having left a bag, rod &c., on the
    ground. He was very intent upon this little book, and we passed
    through unnoticed. We shook hands with our host and hostess,
    and prepared for dinner. I went into the drawing-room, under
    some little awe of this great philosopher, annexing to such a
    character at least the idea of an elderly grave gentleman, not
    perhaps, with so large a wig as Dr. Parr, or so sententious a
    manner as Dr. Johnson,--but certainly I never calculated on being
    introduced to the identical youth, with a little brown head, like
    a boy, that we had seen with his book, and who, when I came into
    the drawing-room was in the most animated manner recounting an
    adventure on the Causeway which had entertained him and from his
    manner of telling it was causing loud laughing in the whole room.”

Davy also spent much of the summer of 1806 in Ireland, and the journal
which he kept during his tour contains many interesting notes of his
impressions of the country and the people. In the course of his journey
he visited Edgeworthstown--“the moral and intellectual paradise of the
author of ‘Castle Rackrent,’” as he calls it. That gifted lady tells
her cousin Sophy Ruxton that as the result her head “was stuffed
full of geological and chemical facts.” “Mr. Davy,” she adds, “is
wonderfully improved since you saw him at Bristol; he has an amazing
fund of knowledge upon all subjects, and a great deal of genius.”

There was much in Davy’s own temperament to make him understand and
appreciate the Irish character; himself a man of quick impulse and
active sympathy, he was profoundly moved by the spectacle of Ireland’s
political degradation. In a letter to his friend Poole, written after
his return to London, he says:--

    “I long very much for the intercourse of a week with you: I have
    very much to say about Ireland. It is an island which might be
    made a new and a great country. It now boasts a fertile soil,
    an ingenious and robust peasantry, and a rich aristocracy; but
    the bane of the nation is the equality of poverty amongst the
    lower orders. All are slaves, without the probability of becoming
    free; they are in the state of equality which the _sans culottes_
    wished for in France; and until emulation, and riches, and the
    love of clothes and neat houses are introduced among them, there
    will be no permanent improvement.

    “Changes in political institutions can, at first, do little
    towards serving them; it must be by altering their habits, by
    diffusing manufactories, by destroying _middlemen_, by dividing
    farms, and by promoting industry by making the pay proportional
    to the work: but I ought not to attempt to say anything on the
    subject when my limits are so narrow; I hope soon to converse
    with you about it.”

With the exception of a rapid journey into Cornwall, for the sake of
seeing his family, he spent the greater part of the summer and autumn
of 1807 in town. He had been made Secretary of the Royal Society in
succession to Gray, and was obliged to be in or near London in order
to see the _Philosophical Transactions_ through the press. From the
Laboratory Journal it would appear that he was occupied at this time on
a variety of disconnected investigations such as the nature of Antwerp
Blue, and the effect of electricity on flame. In a letter to Davies
Gilbert, dated September 12th, he states that he has been a good deal
engaged in experiments on distillation for revenue purposes.

Towards the end of this month, or during the first week of October, he
resumed his experiments with the voltaic battery, and he was led to
study its action on the alkalis. There is some evidence that he had
attacked the same question at Bristol. In a note-book of that period,
under date August 6th, 1800, is the following sentence: “I cannot
close this notice without feeling grateful to M. Volta, Mr. Nicholson,
and Mr. Carlisle, whose experience has placed such a wonderful and
important instrument of analysis in my power”--evidently a jotting to
be used in one of the short communications to Nicholson’s Journal.
This is immediately followed by “Query: Would not potash, dissolved
in spirits of wine, become a conductor?” And he then gives an account
of some experiments on the action of voltaic electricity on aqueous
solutions of ammonia, caustic potash, and hydrochloric acid, which
apparently led to the same result as that already obtained by Nicholson
and Carlisle in the case of water.

It is difficult to determine whether he had any precise idea in again
attacking the problem, or any expectation of a definite result. In one
of his lectures at the Royal Institution on Electro-Chemical Science,
delivered some time subsequently, he said he had a suspicion at that
time that potash might turn out to be “phosphorus, or sulphur united to
nitrogen”:

    “For as the volatile alkali was regarded as composed of an
    extremely light inflammable body--hydrogen--united to nitrogen, I
    conceived that _phosphorus_ and _sulphur_, much denser bodies,
    might produce denser alkaline matter; and as there were no
    _known_ combination of these with _nitrogen_, it was probable
    that there might be unknown combinations.”

Davy once said that “analogy was the fruitful parent of error”; and
the whole history of science probably furnishes no more extraordinary
instance of perverted analogy, or one more unexpected in its
consequences. In another of his lectures he said of the alchemists that
“even their _failures_ developed some unsought-for object partaking of
the marvellous”--and the statement in this case is even more true of
himself. Each phase in the story of this discovery indeed partakes of
the marvellous. Sometime during the first fortnight in October, 1807,
he obtained his first decisive result; and on the 19th of November he
delivered what is generally regarded as the most memorable of all his
Bakerian lectures, “On some new Phenomena of chemical Changes produced
by Electricity, particularly the Decomposition of the fixed Alkalies,
and the Exhibition of the new substances which constitute their bases;
and on the general Nature of alkaline Bodies.” Few discoveries of
like magnitude have been made and perfected in so short a time, and
few memoirs have been more momentous in result than that which Davy
put together in a few hours, and in which he announced his results
to the world. The whole work was done under conditions of great
mental excitement. His cousin Edmund Davy, who at the time acted as
his assistant, relates that when he saw the minute globules of the
quicksilver-like metal burst through the crust of potash and take fire,
his joy knew no bounds; he actually danced about the room in ecstasy,
and it was some time before he was sufficiently composed to continue
his experiments. The rapidity with which he accumulated results after
this first feeling of delirious delight had passed was extraordinary.
Before the middle of November he had obtained most of the leading
facts. In a letter dated November 13th he tells W. H. Pepys--

    “I have decomposed and recomposed the fixed alkalies, and
    discovered their bases to be two new inflammable substances very
    like metals; but one of them lighter than ether, and infinitely
    combustible. So that there are two bodies decomposed, and two new
    elementary bodies found.”

The stories told by Paris of his habits at this period, and of his
various expedients to gain time--of his rushing off to dinner with
persons of the highest rank with no fewer than five shirts on, and as
many pairs of stockings, because in his haste he could not put on fresh
linen without removing that which was underneath; of his continuing
his chemical labours on his return to the laboratory until three or
four in the morning; and of his then being up before the servants, are
certainly much exaggerated, if not wholly apocryphal. He was, it is
true, not very systematic in the disposal of his time, but he seldom
entered the laboratory before ten or eleven in the morning, and rarely
left it later than four, and he was scarcely ever known to visit it
after he had dressed for dinner. Except when preparing a lecture, he
seldom dined in his rooms at the Institution: his brother tells us that
his invitations to dinner were so numerous that he was, or might have
been, constantly engaged; and after dinner he was much in the habit of
attending evening parties, and devoting the evening to amusement, “so
that to the mere frequenters of such parties he must have appeared a
votary of fashion rather than of science.”

It was characteristic of him, that on the very eve of the announcement
of the discovery which raised him to the summit of his scientific
fame, he could unbend the strung bow and thus write to his youngest
sister:--

    “MY DEAR SISTER, ... I looked last week at the pattern of the
    gown that my sister put into my hands, and found it so worn and
    tattered that nothing can be made of it; I cannot therefore get
    your gowns made till you send me another. The best way will be to
    give me measure of the waist, shoulders, length &c., in this way,
    and there can then be no difficulties: thus waist, 15 inches, or
    whatever it may be; between shoulders: length from waist to skirt
    or train.

    “I do not wish to send gowns you cannot wear, and in this way
    they can be well made. By a piece of tape you can easily measure
    and then try the length by a carpenter’s rule, and give me the
    results for yourself, and for Kitty, and Grace, and I shall
    then be able to send your gowns a few days after I receive your
    letter....

    “I shall write to my mother soon, about John. And now, my dear
    sister, having written you as stupid a letter as ever was written
    about gowns, I shall end with love to my mother, Kitty, Grace,
    and my aunts.

            “Your affectionate brother
                              “H. DAVY.”

The Bakerian lecture in which Davy announces the discovery of the
compound nature of the fixed alkalis opens with a reference to the
concluding remarks of his lecture of the previous year, “that the new
methods of investigation promised to lead to a more intimate knowledge
than had hitherto been obtained concerning the true elements of bodies.
This conjecture, then sanctioned only by strong analogies, I am now
happy to be able to support by some conclusive facts.”

In the first attempts he made to decompose the fixed alkalis he acted
upon concentrated aqueous solutions of potash and soda with the highest
electrical power he could then command at the Royal Institution--viz.
from voltaic batteries containing 24 plates of copper and zinc of 12
inches square, 100 plates of 6 inches, and 150 of 4 inches, charged
with solutions of alum and nitric acid; but although there was high
intensity of action nothing but hydrogen and oxygen was disengaged. He
next tried potash in igneous fusion, and here the results were more
encouraging: there were obvious and striking signs of decomposition:
combustible matter was produced accompanied with flame and a most
intense light. He had observed that although potash when dry is a
non-conductor, it readily conducts when it becomes damp by exposure
to air, and in this state “fuses and decomposes by strong electrical
powers.”

    “A small piece of pure potash, which had been exposed for a few
    seconds to the atmosphere, so as to give conducting power to the
    surface was placed upon an insulated disc of platina, connected
    with the negative side of the battery of the power of 250 of 6
    and 4, in a state of intense activity;[G] and a platina wire
    communicating with the positive side was brought in contact with
    the upper surface of the alkali....

    “Under these circumstances a vivid action was soon observed
    to take place. The potash began to fuse at both its points
    of electrization. There was a violent effervescence at the
    upper surface; at the lower, or negative surface, there was
    no liberation of elastic fluid; but small globules having a
    high metallic lustre, and being precisely similar in visible
    characters to quicksilver appeared, some of which burnt with
    explosion and bright flame, as soon as they were formed, and
    others remained, and were merely tarnished, and finally covered
    by a white film which formed on their surfaces.”

    [G] It is frequently stated that Davy was enabled to isolate
        the metals of the alkalis because of the _large_ and
        powerful voltaic battery which he had at his disposal in
        the Royal Institution. This is not correct. The battery he
        employed was of very moderate dimensions, and not by any
        means extraordinary in power. It was the success he thus
        achieved that caused the large battery, which is probably
        referred to, to be constructed, by special subscription, in
        1809.

The platina, as such, was, he found, in no way connected with the
result: a substance of the same kind was produced when copper, silver,
gold, plumbago, or even charcoal was employed for completing the
circuit.

    “Soda when acted upon in the same manner as potash, exhibited
    an analogous result; but the decomposition demanded greater
    intensity of action in the batteries, or the alkali was required
    to be in much thinner and smaller pieces.”

    “The substance produced from potash remained fluid at the
    temperature of the atmosphere at the time of its production; that
    from soda, which was fluid in the degree of heat of the alkali
    during its formation, became solid on cooling, and appeared
    having the lustre of silver.”

It would seem from his description of its properties that the potassium
he obtained was most probably alloyed with sodium derived from impure
potash. Potassium is solid up to 143° F.; but, as Davy subsequently
found, an alloy of potassium and sodium is fluid at ordinary
temperatures.

When the potassium was exposed to air its metallic lustre was
immediately destroyed, and it was ultimately wholly reconverted into
potash by absorption of oxygen and moisture.

With the substance from soda the appearance and effects were analogous.

When heated in oxygen to a sufficiently high temperature, both
substances burnt with a brilliant white flame.

On account of their alterability on exposure to air, Davy had
considerable difficulty in preserving and confining them so as to
examine the properties of the new substances. As he says, like the
_alkahests_ imagined by the alchemists, they acted more or less upon
almost every body to which they were exposed.

He eventually found that they might be preserved in naphtha.

The “basis” of potash at 50° F. was a soft and malleable solid with the
lustre of polished silver.

    “At about the freezing point of water it becomes harder and
    brittle, and when broken in fragments, exhibits a crystallized
    texture, which in the microscope seems composed of beautiful
    facets of a perfect whiteness and high metallic splendour.”

It may be converted into vapour at a temperature approaching a
red-heat, and may be distilled unchanged; it is a perfect conductor
of electricity and an excellent conductor of heat. Its most marked
difference from the common run of metals was its extraordinarily low
specific gravity. Davy endeavoured to gain an approximation to its
relative weight by comparing the weight of a globule with that of an
equal-sized globule of mercury.

    “Taking the mean of 4 experiments, conducted with great care,
    its specific gravity at 62° Fahrenheit, is to that of mercury as
    10 to 223, which gives a proportion to that of water nearly as 6
    to 10; so that it is the lightest fluid body known. In its solid
    form it is a little heavier.”

Although no great stress can be laid on numbers so obtained, they serve
to indicate that Davy had not yet obtained the pure metal. The real
ratio of the specific gravities of potassium and mercury is as 10 to
154.

An account is then given of the behaviour of potassium towards oxygen,
oxymuriatic acid gas [chlorine], hydrogen, water, alcohol, ether,
the various mineral acids, phosphorus, sulphur, mercury, a number of
metallic oxides, and the various forms of glass.

The “basis” of soda is described as a white opaque substance of the
lustre and general appearance of silver. It is soft and malleable, and
is a good conductor of heat and electricity. Its specific gravity was
found by flotation in a mixture of oil of sassafras and naphtha to be
0·9348 (the true specific gravity of sodium is 0·974). It was found to
fuse at about 180° F. (the real melting-point of sodium is 197·5°). Its
action on a number of substances--oxygen, hydrogen, water, etc.--is
then described, and its general behaviour contrasted with that of the
“basis” of potash.

Davy then attempted, by synthetical experiments, to determine the
amount of the “metallic bases” in potash and soda respectively, and,
considering the extremely small quantities he had to operate upon, the
results are fairly accurate.

He then enters upon some general observations on the relations of the
“bases” of potash and soda to other bodies.

    “Should the bases of potash and soda be called metals? The
    greater number of philosophical persons to whom this question
    has been put, have answered in the affirmative. They agree with
    metals in opacity, lustre, malleability, conducting powers as
    to heat and electricity, and in their qualities of chemical
    combination.

    “Their low specific gravity does not appear a sufficient reason
    for making them a new class; for amongst the metals themselves
    there are remarkable differences in this respect, ... and in the
    philosophical division of the classes of bodies, the analogy
    between the greater number of properties must always be the
    foundation of arrangement.

    “On this idea, in naming the bases of potash and soda, it will
    be proper to adopt the termination which, by common consent, has
    been applied to other newly discovered metals, and which, though
    originally Latin, is now naturalized in our language.

    “Potasium [_sic_] and sodium are the names by which I have
    ventured to call the new substances; and whatever changes of
    theory, with regard to the composition of bodies, may hereafter
    take place, these terms can scarcely express an error; for
    they may be considered as implying simply the metals produced
    from potash and soda. I have consulted with many of the most
    eminent scientific persons in this country, upon the methods of
    derivation, and the one I have adopted has been the one most
    generally approved. It is perhaps more significant than elegant.
    But it was not possible to found names upon specific properties
    not common to both; and though a name for the basis of soda might
    have been borrowed from the Greek, yet an analogous one could not
    have been applied to that of potash, for the ancients do not seem
    to have distinguished between the two alkalies.”

He thinks there is the greater necessity for avoiding any theoretical
views in terms because the time is yet far distant for a complete
generalisation of chemical facts, and although the antiphlogistic
explanation of the phenomena has been uniformly adopted, the motive for
employing it has been rather a sense of its beauty and precision than a
conviction of its permanency and truth.

    “The discovery of the agencies of the gases destroyed the
    hypothesis of Stahl. The knowledge of the powers and effects
    of the etherial substances may at a future time possibly act
    a similar part with regard to the more refined and ingenious
    hypothesis of Lavoisier; but in the present state of our
    knowledge, it appears the best approximation that has been made
    to a perfect logic of chemistry.”

Led by analogy, Davy soon convinced himself that the volatile
alkali--ammonia--also contained oxygen, and in amount not less than 7
or 8 per cent. It is not necessary to go into detail concerning the
experiments on which this erroneous conclusion was founded. Davy was
subsequently made aware of his error; but at the time he seemed anxious
to overturn--as, indeed, he did in the end, but on other grounds--the
Lavoisierian doctrine that oxygen was the principle of acidity, by
showing that it was equally the principle of alkalescence.

In concluding his paper, he mentions that he has begun experiments on
the alkaline earths.

    “From analogy alone it is reasonable to expect that the alkaline
    earths are compounds of a similar nature to the fixed alkalies,
    peculiar highly combustible metallic bases united to oxygen. I
    have tried some experiments upon barytes and strontites, and they
    go far towards proving that this must be the case.”

    “Barytes and strontites have the strongest relations to the
    fixed alkalies of any of the earthy bodies; but there is a chain
    of resemblances through lime, magnesia, glucina, alumina, and
    silex. And by the agencies of batteries sufficiently strong, and
    by the application of proper circumstances, there is no small
    reason to hope that even these refractory bodies will yield their
    elements to the methods of analysis by electrical attraction and
    repulsion.”

Although certain of the conjectures with which the paper terminates
have been proved to be erroneous, others have been shown to be sound.
Thus he points out that the metals of the alkalis will undoubtedly
prove powerful agents for analysis:

    “Having an affinity for oxygen stronger than any other known
    substances they may possibly supersede the application of
    electricity to some of the undecompounded bodies.”

Such is a brief summary of the contents of one of the most classical
papers in the _Philosophical Transactions_. Its publication created an
extraordinary sensation, not less profound, and certainly more general
from the very nature of the subject, than that which followed his first
Bakerian lecture. That potash and soda should contain metals--and such
metals!--was undreamt of, and was a shock to the settled convictions
of persons who, like the Aberdonian professor, declared that this “ane
Davy was a vera troublesome person in chemistry.”

But this “troublesome person” had well nigh ceased from troubling
any more. Almost immediately after the delivery of his lecture he
collapsed--struck down by an illness which nearly proved fatal, and
for weeks his life hung on a thread. He had been in a low feverish
condition for some time previously, and a great dread had fallen upon
him that he should die before he had completed his discoveries. It
was in this condition of body and mind that he applied himself to
the task of putting together an account of his results. Four days
after this was given to the world he took to his bed, and he remained
there for nine weeks. Such a blow following hard on such a triumph,
aroused the liveliest sympathy. The doors of the Royal Institution
were beset by anxious inquirers. His physicians, Babington, Frank, and
Baillie, tended him with the greatest assiduity. Mrs. Greenwood, the
housekeeper, and his cousin, Edmund Davy, nursed him night and day. So
great was the popular feeling that, when he was at the worst, written
reports of his condition at various periods of the day had to be posted
in the hall. The strength of the feeling may be gleaned, too, from the
sentences with which Dr. Dibdin began his lecture introductory to the
session of 1808:--

    “The Managers of this Institution have requested me to impart
    to you that intelligence, which no one who is alive to the best
    feelings of human nature can hear without the mixed emotions of
    sorrow and delight.

    “Mr. Davy, whose frequent and powerful addresses from this place,
    supported by his ingenious experiments, have been so long and so
    well known to you, has for the last five weeks been struggling
    between life and death. The effects of these experiments recently
    made in illustration of his late splendid discovery, added to
    consequent bodily weakness, brought on a fever so violent as to
    threaten the extinction of life. Over him it might emphatically
    be said in the language of our immortal Milton, that

        ‘... Death his dart
    Shook, but delayed to strike.’

    “If it had pleased Providence to deprive the world of all further
    benefit from his original talents and intense application there
    has certainly been sufficient already effected by him to entitle
    him to be classed among the brightest scientific luminaries of
    his country.”

After having given an outline of Davy’s investigations “at the
particular request of the Managers,” Dr. Dibdin proceeds:--

    “These may justly be placed amongst the most brilliant and
    valuable discoveries which have ever been made in chemistry,
    for a great chasm in the chemical system has been filled up; a
    blaze of light has been diffused over that part which before was
    utterly dark; and new views have been opened, so numerous and
    interesting, that the more any man who is versed in chemistry
    reflects on them, the more he finds to admire and to heighten his
    expectation of future important results.

    “Mr. Davy’s name, in consequence of these discoveries, will be
    always recorded in the annals of science amongst those of the
    most illustrious philosophers of his time. His country with
    reason will be proud of him, and it is no small honour to the
    Royal Institution that these great discoveries have been made
    within its walls; in that laboratory, and by those instruments,
    which from the zeal of promoting useful knowledge have, with so
    much propriety, been placed at the disposal and for the use of
    its most excellent professor of chemistry.”

Dr. Dibdin then informs his auditors that Davy’s illness, severe as it
had been, was now beginning to abate, and that it may be reasonably
hoped that the period of convalescence was not very remote.

His bodily weakness, however, continued for some time, and it was not
until the middle of March that he was able to resume his duties as
lecturer. His mind, as his note-books show, much more quickly recovered
its wonted vigour. Perhaps it was in that condition of melancholy and
debility produced by sickness, which he regarded as favourable to
intellectual exertion, when, as he says, “the mind necessarily becomes
contemplative when the body is no longer active, and the empire of
sensation yields to that of imagination,” that he finished the poem
beginning:--

    “Lo! o’er the earth the kindling spirits pour
      The flames of life that bounteous Nature gives;
    The limpid dew becomes the rosy flower,
      The insensate dust awakes, and moves, and lives.”

It is too long to give here, but of all his poetical effusions it is
perhaps the best, as it certainly is the most highly-polished.

One proof of what Davy was to the Royal Institution is seen in the
position to which it was reduced in consequence of his protracted
illness. In the early part of the previous December the Managers made
the following announcement:--

    “Mr. Davy, having been confined to his bed this last fortnight by
    a severe illness, the Managers are under the painful necessity of
    giving notice that the lectures will not commence until the first
    week of January next.”

By the interruption of the lectures the income of the Institution
was greatly diminished; it fell from £4,141 in the preceding year to
£1,560. This was the low-water mark of its financial state. How acute
was the condition may be seen from the report of the Visitors in 1808.

Davy, although better, was still in bed, confined there by the want
of a sofa in his room. This was not provided by the Managers until
January 25th, when, as the minutes tell us, they furnished him with one
at a cost of three guineas. One would have thought he might have had
Albemarle Street blocked with sofas if some of those lady-friends who
sent him sonnets, and intrigued for his company at their salons, had
only known of his condition.

The laboratory journals show that on April 19th he was able to resume
his experiments, and that he proceeded to attack the composition
of muriatic [hydrochloric] acid. The note runs, “Indications of the
decomposition of muriatic acid. To use every effort to ensure accuracy
in the results.” He seems to have decomposed muriatic acid gas by means
of charcoal terminals, and also to have acted on a mixture of dry
calcium chloride and mercury.

On June 30th he contributed a paper to the Royal Society on
“Electro-Chemical Researches on the Decomposition of the Earths; with
Observations on the Metals obtained from the alkaline Earths, and on
the Amalgam procured from Ammonia.”

That the earths would turn out to be related to the metals was surmised
by Becher and Stahl. Boyle considered it possible that metals might
be produced from them, and Neumann described unsuccessful experiments
to obtain a metal from quicklime. Bergman imagined that baryta was
a metallic calx, and Baron that alumina contained a metal. The
supposition that the calces were all compounds of metals was, of
course, a part of the antiphlogistic doctrine; but Lavoisier never
hazarded any conjecture as to the nature of potash and soda. It went
almost without saying therefore that when Davy had demonstrated the
real character of the fixed alkalis, the alkaline earths would be found
to have an analogous constitution.

The attempts made by Davy to decompose the alkaline earths by methods
similar to those adopted in the case of potash or soda were not
very successful, and it was only when he had received intimation
from Berzelius that they might be procured in the form of amalgams
by operating in contact with mercury that he obtained any decisive
results. In no case, however, was he able to prepare a pure metal,
and his description of the physical properties of the substances
he actually procured is exceedingly meagre. He seems to have been
satisfied for the moment in demonstrating that--

    “The evidence for the composition of the alkaline earths is of
    the same kind as that for the composition of the common metallic
    oxides; and the principles of their decomposition are precisely
    similar, the inflammable matters in all cases separating at the
    negative surface in the voltaic circuit, and the oxygen at the
    positive surface.”

    “These new substances will demand names; and on the same
    principles as I have named the bases of the fixed alkalies,
    potassium and sodium, I shall venture to denominate the metals
    from the alkaline earths barium, strontium, calcium and magnium;
    the last of these words is undoubtedly objectionable but
    magnesium has been already applied to metallic manganese [by
    Bergman] and would consequently have been an equivocal term.”

However, as he states in his “Elements of Chemical Philosophy,” “the
candid criticisms of some philosophical friends” induced him to
subsequently change the name to magnesium.

He next made “Inquiries Relative to the Decomposition of Alumine,
Silex, Zircone, and Glucine,” but although he made a large number of
trials, the results were equivocal.

    “Had I been so fortunate,” he says, “as to have obtained more
    certain evidences on this subject, and to have procured the
    metallic substances I was in search of, I should have proposed
    for them the names of silicium, alumium, zirconium, and glucium.”

One of the most interesting sections of the paper relates to the
production of a so-called amalgam from ammonia, first obtained by
Berzelius and Pontin. This curious substance has been the subject of
much investigation, and little doubt is now entertained that it is
merely a mercurial froth, as first stated by Daniell--that is, mercury
distended by ammonia and hydrogen gases. Davy, however, saw in it the
proof of the presence of oxygen in ammonia, and of the existence of
what he called “the compound basis” of ammonia. He says:--

    “The more the properties of the amalgam obtained from ammonia
    are considered the more extraordinary do they appear. Mercury by
    combination with about 1/12000 part of its weight of new matter
    is rendered a solid, yet has its specific gravity diminished
    from 13·5 to 3, and it retains all its metallic characters;
    its colour, lustre, opacity, and conducting powers remaining
    unimpaired. It is scarcely possible to conceive that a substance
    which forms with mercury so perfect an amalgam, should not be
    metallic in its own nature; and on this idea to assist the
    discussion concerning it, it may be conveniently termed ammonium.”

Davy’s term “ammonium” is still retained in chemical nomenclature, but
there is at present no evidence for the independent existence of such
an entity; the so-called ammonium amalgam is certainly no proof.

On December 15th, 1808, he delivered his third Bakerian lecture. It was
entitled “An Account of some new analytical Researches on the Nature
of certain Bodies, particularly the Alkalies, Phosphorus, Sulphur,
Carbonaceous Matter, and the Acids hitherto undecompounded, with some
general Observations on Chemical Theory.” Although this is one of
the longest and most laboured of Davy’s papers, it is, perhaps, one
of the least satisfactory. It is a record of many experiments with
few definite results. Few as these were, they yet paved the way for
consequences of the greatest importance. Gay Lussac and Thenard, on the
publication of Davy’s second Bakerian lecture, succeeded in devising a
method by which larger quantities of potassium might be obtained than
by the electrolytic process. It consisted in passing molten potash
over heated metallic iron and condensing the volatilised potassium in
naphtha. On heating potassium in ammonia, they found that hydrogen was
obtained together with potash, whence they concluded that potassium
was a _hydruret of potash_. This experiment was repeated by Davy; he
observed the formation of a substance since known as _potassamide_,
and completely disproved the conjecture of the French chemists. His
experiments on sulphur, phosphorus, and the various forms of carbon
were, however, wholly fallacious, and his conclusions as to the
non-elementary nature of these substances were erroneous, and were
subsequently corrected by him. His work on the decomposition of boracic
acid is, however, accurate, and he has every right to be considered as
an independent discoverer, with Thenard, of the element subsequently
called by him _boron_. At first Davy was inclined “to consider the
boracic basis as metallic in its nature,” and to propose for it the
name of _boracium_. His experiments with “fluoric acid” were vitiated
by the circumstance that he worked with a mixture of hydrofluoric
acid and silicon fluoride. Unwittingly he obtained small quantities
of silicon, although he failed to recognise the individuality of this
substance. Nor were the experiments with muriatic acid more decisive.
Incidentally he obtained the two chlorides of phosphorus, but for a
time their true nature escaped him, although he gives a fairly accurate
description of their main properties.

The paper, although containing an account of much experimental work,
was evidently put together in haste; it would have been better for
his reputation had he delayed its publication. He seems to have been
conscious of its imperfections, and to have sought to strengthen his
conclusions by new experiments which he gives in an appendix. These,
so far from substantiating his views, increased his doubts, and it
is remarkable how he misinterpreted the phenomena he observed. Thus
in one series of experiments he obtained considerable quantities of
the “alcohol of sulphur of Lampadius,” and attempted to ascertain its
nature, but his preconceptions as to the non-elementary nature of
carbon and sulphur prevented him from recognising that it is a sulphide
of carbon.

One explanation of this untoward haste is to be found in the position
in which Davy was placed. He simply _hungered_ for scientific fame,
and his appetite grew by what it fed on. There was at the time
the most intense spirit of rivalry between the English and French
chemists--it was a phase of the national feeling which actuated the
two peoples--and, in spite of his phrases, Davy keenly felt what he
considered an intrusion into his own field of work. His illness had
thrown him back, and the French chemists had stolen a march on him
in the meantime. Moreover, he had Berzelius on his flank. All these
circumstances, whilst they impelled him to activity, were unfavourable
in a man of Davy’s temperament to the incubatory period, “the wambling
in the wame” process, which is often needed before the true aspect and
meaning of things are perceived; and there is no doubt that the fear
of being anticipated urged him to the expression of hypotheses and
surmises which at a later and calmer period he regretted and renounced.

But such was his position in England at this period, that a Bakerian
lecture seemed to be expected from him at each succeeding session of
the Royal Society as a matter of course, and he was always ready to
respond to the expectation, even if he did not invariably satisfy it.

On November 16th, 1809, he read his fourth Bakerian lecture. It
was “On some new Electrochemical Researches on various Objects,
particularly the metallic Bodies, from the Alkalies and Earths, and on
some Combinations of Hydrogene.” He begins by again drawing attention
to the various surmises which had been made respecting the true nature
of potassium and sodium. Although these substances had been isolated,
and in the hands of chemists for upwards of two years, their properties
were so extraordinary when compared with those of the metals in
general, that many philosophers hesitated to consider them as true
metals. Gay Lussac and Thenard, as already mentioned, regarded them as
compounds of potash or soda with hydrogen; Curaudau as combinations of
carbon or carbon and hydrogen with the alkalis; whilst an ingenious
inquirer in this country communicated to Nicholson’s Journal his
belief that they were really composed of oxygen and hydrogen! Davy,
in the light of the fuller knowledge he obtained from Gay Lussac and
Thenard’s paper in the “Mem. d’Arcueil”--a copy of which he owed to
Berthollet--had no difficulty in again proving “that by the operation
of potassium upon ammonia, it is not a _metallic_ body that is
decompounded, but the volatile alkali, and that the hydrogen produced
does not arise from the potassium, as is asserted by the French
chemists, but from the _ammonia_.”

M. Curaudau’s hypothesis is shown to be based upon the accidental
association of naphtha with the metals he employed. In repeating some
experiments of Ritter’s, designed to show that potassium contained
hydrogen, Davy was led to the discovery of _telluretted hydrogen_, the
properties of which he describes in some detail. Tellurium at that time
was regarded as a metal, but Davy points out its strong analogies to
sulphur, with which element, indeed, it is now classed. Incidentally
he throws light upon the nature of the intolerably fetid product known
as “the fuming liquor of Cadet,” obtained by distilling acetate of
potash with arsenious oxide. On account of its extreme inflammability,
it was thought by Davy that this liquid might possibly be a pyrophorus
or volatile alloy of potassium and arsenic.

    “From a repetition of the process I find that though potash is
    decompounded in this operation yet that the volatile substance
    is not an alloy of potassium but contains charcoal and arsenic
    probably with hydrogen. The gases not absorbable by water given
    off in this operation are peculiar. Their smell is intensely
    fetid. They are inflammable, and seem to contain charcoal,
    arsenic and hydrogen: whether they are mixtures of various gases,
    or a single compound, I am not at present able to decide.”

So far as it goes, this description of the nature of the substance
is correct; it was Bunsen, in 1837, who first demonstrated the real
character of “the fuming liquor of Cadet.”

The paper is noteworthy for the clear distinction which is drawn for
the first time between potash hydrate (potassium hydroxide of modern
nomenclature) and potassium oxide, the product formed by heating the
metal in ordinary oxygen.

There is much in the rest of the paper that is ingenious and
suggestive, and not a few isolated facts that seem to have been lost
sight of, or rediscovered by subsequent observers, such, for example,
as the action of potassium upon metallic iron--an action which has
vitiated the attempts to determine the vapour density of that metal in
iron vessels. It is curious to note with what persistency Davy clings
to the belief that nitrogen will turn out to be a compound substance,
and with what pertinacity he importunes it to give up its components.
At times he thinks he is on the verge of proof. “I hope on Thursday,”
he wrote to his friend Children, “to show you nitrogen as a complete
wreck, torn to pieces in different ways.” But still nitrogen, with
that passive immutability which is characteristic of it, in spite of
every form of torture, remained whole and indissoluble. On this point
he wrote in the Laboratory Journal under date February 15th:--“Were a
description, indeed, to be given of all the experiments I have made,
of all the difficulties I have encountered, of the doubts that have
occurred, and the hypotheses formed----.” But the sentence was not
finished. The attack was renewed and continued throughout the whole of
the spring and summer, until, fairly baffled, Davy confessed himself
beaten, and turned his attention to other matters. The condition of his
laboratory at this time may be gleaned from the following note in the
Journal:--

    “Objects much wanted in the laboratory of the Royal Institution:
    cleanliness, neatness and regularity.

    “The laboratory must be cleaned every morning when operations are
    going on before ten o’clock.

    “It is the business of W. Payne to do this, and it is the duty of
    Mr. E. Davy to see that it is done and to take care of and keep
    in order the apparatus.

    “There must be in the laboratory pen, ink, paper, and wafers, and
    these must not be kept in the slovenly manner in which they are
    usually kept. I am now writing with a pen and ink such as was
    never used in any other place.”

Then follows a list of articles wanting, “including most of the common
metallic and saline solutions.”

    “The laboratory is constantly in a state of dirt and confusion.

    “There must be a roller with a coarse towel for washing the hands
    and a basin of water and soap, and every week at least a whole
    morning must be devoted to the inspection and ordering of the
    voltaic battery.”

It would be interesting to know the comments of the persons named in
this note as to the cause of the dirt and confusion which reigned in
the laboratory. Davy was perfectly reckless with apparatus; with him
to think was to act, and he frequently had half a dozen experiments
going on simultaneously, upon disconnected parts of the same inquiry.
Anyone who has had the opportunity of seeing his laboratory notes,
or of glancing over the rough drafts of his memoirs, which have
been preserved by the pious care of Faraday, will appreciate the
significance of the remarks upon his writing materials. His usual
method of erasure was by dipping his finger in the ink-pot; and, if we
may be pardoned the use of the colloquialism, he was simply “Death on
pens!”




CHAPTER VII.

CHLORINE.


The rivalry between the French and English chemists continued, but it
took a new departure. Gay Lussac and Thenard had stolen a march on
Davy by their discovery of a chemical method of making the metals of
the alkalis, whereby they were able to use these metals as chemical
reagents to greater advantage; but the tables were quickly turned. On
July 12th, 1810, Davy read to the Royal Society his memorable paper “On
the oxymuriatic Acid, its Nature and Combinations; and on the Elements
of the muriatic Acid; with some Experiments on Sulphur and Phosphorus,
made in the Laboratory of the Royal Institution.” This paper, in which
he first demonstrates the nature of chlorine, is very short--only some
twenty-six quarto pages--but it is unquestionably one of the most
brilliant, as it is one of the most forcible of his productions.

Davy is here seen at his best. He is bold and yet wary, and as
dexterous as trenchant; so confident is he in the strength of his
position that he casts aside every argument that might tell in his
favour, unless it is based on the most unimpeachable evidence. It is
difficult to know what to admire most--the clearness of perception, the
precision of the statement, the strictness of the logic, the aptness
of the illustration, or the argumentative skill with which the whole
is marshalled and presented. As a piece of induction, the memoir is a
model of its kind, and as an exercise in “the scientific use of the
imagination” it has few equals. Most scientific papers will stand a
considerable amount of winnowing, and there is no assay-master more
scrupulously strict than Time. “The more a science advances, the more
it becomes concentrated in little books,” says Leibnitz; but the most
fastidious of critics might read and re-read this work without wishing
to omit or amend a sentence.

Every chemical student to-day is told that the elementary nature of
chlorine was first _demonstrated_ by Davy, and if the student is
informed what Davy meant by the term “element,” the statement is not
incorrect. What, however, Davy actually did was to demonstrate that
the substance called oxymuriatic acid contained no oxygen; that it was
a peculiar substance which “has not as yet been decompounded,” and
therefore is “elementary as far as our knowledge extends.” The very
character of the name which he suggested indicates this cautious and
philosophical view. In making the suggestion, he says:--

    “To call a body which is not known to contain oxygen and which
    cannot contain muriatic acid, oxymuriatic acid, is contrary to
    the principles of that nomenclature in which it is adopted;
    and an alteration of it seems necessary to assist the progress
    of discussion, and to diffuse just ideas on the subject. If the
    great discoverer of this substance [Scheele, who first observed
    it in 1774] had signified it by any simple name, it would have
    been proper to have recurred to it; but, _dephlogisticated marine
    acid_ is a term which can hardly be adopted in the present
    advanced era of the science.

    “After consulting some of the most eminent chemical philosophers
    in this country, it has been judged most proper to suggest
    a name founded upon one of its obvious and characteristic
    properties--its colour, and to call it _chlorine_, or _chloric_
    gas.[H]

    “Should it hereafter be discovered to be compound, and even
    to contain oxygen, this name can imply no error, and cannot
    necessarily require a change.”

    [H] [From χλωρος.]

As the actual facts and arguments on which Davy based his views
are seldom set forth in text-books, or presented to the student by
teachers, it may be desirable to give a detailed account of his famous
memoir. He begins by saying:--

    “The illustrious discoverer of the oxymuriatic acid considered
    it as muriatic acid freed from hydrogen; and the common muriatic
    acid as a compound of hydrogen and oxymuriatic acid; and on this
    theory he denominated oxymuriatic acid dephlogisticated muriatic
    acid.

    “M. Berthollet, a few years after the discovery of Scheele, made
    a number of important and curious experiments on this body; from
    which he concluded that it was composed of muriatic acid and
    oxygen; and this idea for nearly twenty years has been almost
    universally adopted.”

Having thus accurately stated the position, he proceeds to attack it.
In the first place, he points out that Henry, ten years before, had
shown that hydrogen could be produced from muriatic acid gas by the
agency of electricity; this hydrogen was assumed by Henry to be due to
water contained in the gas. Davy, in his Bakerian lecture of 1808, had
shown that muriatic acid gas gave hydrogen when treated with potassium,
and he had stated “that muriatic acid can in no instance be procured
from oxymuriatic gas, or from dry muriates, unless water or its
elements be present.”

Gay Lussac and Thenard had concluded “that muriatic acid gas contains
about one-quarter of its weight of water; and that oxymuriatic acid is
not _decomposable_ by any substances but hydrogen, or such as can form
triple combinations with it.”

He then points out, what he had already stated in a former paper, that
charcoal freed from hydrogen and moisture by intense ignition _in
vacuo_ may be heated to whiteness by the voltaic battery in oxymuriatic
or muriatic acid gases without affecting any change in them.

It now occurred to him that if the liquor of Libavius (stannic
chloride) is a combination of muriatic acid and oxide of tin, as then
surmised, oxide of tin ought to be separated from it by means of
ammonia. On admitting ammonia gas to the tin chloride over mercury, the
substances combined with great heat, a white solid was obtained; “some
of it was heated to ascertain if it contained oxide of tin, but the
whole volatilised, producing dense pungent fumes.” The experiment was
repeated with every care, but no oxide of tin could be obtained.

He was next led to study the behaviour of ammonia with the substances
he had formerly obtained, by the action of oxymuriatic gas on
phosphorus (see p. 129). One of these is solid, and is now known as
phosphorus pentachloride; the other is liquid, and is termed phosphorus
trichloride.

    “The first,” he says, “on the generally received theory of the
    nature of oxymuriatic acid, must be considered as a compound of
    muriatic acid and phosphoric acid. It occurred to me that if the
    acids of phosphorus really existed in these combinations, it
    would not be difficult to obtain them, and thus to gain proof of
    the existence of oxygen in oxymuriatic acid.”

He therefore brought ammonia gas into contact with the solid compound
of oxymuriatic acid and phosphorus. Much heat was produced, and a white
opaque powder was formed.

    “Supposing that this substance was composed of the dry muriate
    and phosphate of ammonia; as muriate of ammonia is very volatile,
    and as ammonia is driven off from phosphoric acid, by a heat
    below redness I conceived that by igniting the product obtained
    I should procure phosphoric acid ... but found to my great
    surprise that it was not at all volatile nor decomposable at
    this degree of heat, and that it gave off no gaseous matter. The
    circumstance that a substance composed principally of oxymuriatic
    acid and ammonia should resist decomposition or change at so
    high a temperature induced me to pay particular attention to the
    properties of this new body.”

What he actually obtained was mainly a mixture of the so-called
_phospham_ and _chlorophosphamide_, remarkably stable substances,
the characteristic properties of which he describes with accuracy.
He then examined the action of ammonia gas on sulphur chloride, “the
sulphuretted muriatic liquor of Dr. Thomson,” but as the compounds
formed

    “did not present the same uniform and interesting properties
    as that from the phosphoric sublimate, I did not examine them
    minutely: I contented myself by ascertaining that no substance
    known to contain oxygen could be procured from oxymuriatic acid
    in this mode of operation.”

He then shows that ammonia and oxymuriatic acid, in condensing to sal
ammoniac with liberation of nitrogen, contrary to the general belief,
form no water. According to Cruickshank, who appears to have been the
first to make the observation, “hydrogenous gas” required rather more
than its own volume of oxygenated muriatic acid to saturate it when a
mixture of the two was exploded by means of the electric spark, “the
products being water and muriatic acid.” Gay Lussac and Thenard had
stated that no water was thus formed.

    “I have attempted,” says Davy, “to make the experiment still
    more refined by drying the oxymuriatic acid and the hydrogen
    by introducing them into vessels containing muriate of lime
    [calcium chloride] and by suffering them to combine at common
    temperatures; but I have never been able to avoid a slight
    condensation; though in proportion as the gases were free from
    oxygen or water, this condensation diminished.[I]

    “MM. Gay Lussac and Thenard have proved by a copious collection
    of instances, that in the usual cases where oxygen is procured
    from oxymuriatic acid, water is always present, and muriatic acid
    gas is formed; now as it is shewn that oxymuriatic acid gas is
    converted into muriatic acid gas by combining with hydrogen, it
    is scarcely possible to avoid the conclusion, that the oxygen is
    derived from the decomposition of the water, and consequently
    that the idea of the existence of water in muriatic acid gas, is
    hypothetical, depending upon an assumption which has not yet been
    proved--the existence of oxygen in oxymuriatic acid gas.

    “MM. Gay Lussac and Thenard indeed have stated an experiment,
    which they consider as proving that muriatic acid gas contains
    one-quarter of its weight of combined water. They passed this gas
    over litharge, and obtained so much water; but it is obvious,
    that in this case, they formed the same compound as that produced
    by the action of oxymuriatic acid on lead; and in this process
    the muriatic acid must lose its hydrogen and the lead its oxygen;
    which of course would form water; these able chemists, indeed,
    from the conclusion of their memoir, seem aware, that such an
    explanation may be given, for they say, that the oxymuriatic acid
    _may_ be considered as a simple body.”

    [I] Theoretically, there should be no contraction. One volume
        of chlorine combines with one volume of hydrogen to form
        two volumes of hydrogen chloride [muriatic acid gas].
        Dalton’s law of gaseous volumes had been established by Gay
        Lussac before 1810.

He then repeats the experiments which first led him to suspect the
existence of combined water in muriatic acid.

    “When mercury is made to act upon 1 volume of muriatic acid gas,
    by voltaic electricity, all the acid disappears, calomel is
    formed, and about ·5 of hydrogen evolved.”

The same result is obtained by the use of potassium.

    “And in some experiments made very carefully by my brother, Mr.
    John Davy, on the decomposition of muriatic acid gas, by heated
    tin and zinc, hydrogen, equal to about half its volume, was
    disengaged, and metallic muriates, the same as those produced by
    the combustion of tin and zinc in oxymuriatic gas, resulted.”

    “It is evident from this series of observations, that Scheele’s
    view (though obscured by terms derived from a vague and unfounded
    general theory) of the nature of the oxymuriatic and muriatic
    acids, may be considered as an expression of facts; whilst the
    view adopted by the French school of chemistry, and which, till
    it is minutely examined, appears so beautiful and satisfactory
    rests in the present state of our knowledge upon hypothetical
    grounds.”

He then proceeds to explain the action of water upon the chlorides of
tin, and phosphorus; and shows that it is by the decomposition of the
water that the hydrogen is furnished to the oxymuriatic acid, and the
oxygen to the tin and phosphorus.

    “The vivid combustion of bodies in oxymuriatic acid gas, at first
    view, appears a reason why oxygen should be admitted in it;
    but heat and light are merely results of the intense agency of
    combination. Sulphur and metals, alkaline earths and acids become
    ignited during their mutual agency; and such an effect might be
    expected in an operation so rapid as that of oxymuriatic acid
    upon metals and inflammable bodies.”

    “That the quantity of hydrogen evolved during the decomposition
    of muriatic acid gas by metals, is the same that would be
    produced during the decomposition of water by the same bodies,
    appears, at first view, an evidence in favour of the existence
    of water in muriatic acid gas; but as there is only one known
    combination of hydrogen with oxymuriatic acid, one quantity must
    always be separated. Hydrogen is disengaged from its oxymuriatic
    combination by a metal, in the same manner as one metal is
    disengaged by another from similar combinations.”

He once more shows that by the strongest analytical power he can
command oxymuriatic acid fails to yield any substance differing from
itself:

    “I have caused strong explosions from an electrical jar, to pass
    through oxymuriatic gas, by means of points of platina, for
    several hours in succession; but it seemed not to undergo the
    slightest change.”

Such, then, are the reasons which induced Davy to consider that
oxymuriatic acid contains no oxygen; that it had hitherto been
“undecompounded,” and that, therefore, by the strict logic of
chemistry, it was to be regarded as an elementary body. Had his paper
concluded at this point, his position would have been unassailable,
even in the light of nearly ninety years of subsequent work. But
he could not stop here. Berthollet, the author of the prevailing
theory, had discovered a salt then known as _hyper-oxymuriate_
of potash, presumably capable of furnishing an acid termed by
Chenevix _hyper-oxygenised muriatic acid_. This salt is now termed
potassium chlorate, after the acid which Davy subsequently succeeded
in isolating, and which, when the chlorine theory was generally
accepted, was called chloric acid by Gay Lussac. The existence of the
hyper-oxymuriate of potash was for a time a stumbling-block, and Davy
sought to explain it on the assumption that it was nothing more than a
triple compound of oxymuriatic acid, potassium, and oxygen.

    “We have no right to assume the existence of any peculiar acid
    in it, or of a considerable portion of combined water; and it is
    perhaps more conformable to the analogy of chemistry to suppose
    the large quantity of oxygen combined with the potassium, which
    we know has an intense affinity for oxygen, and which from some
    experiments, I am inclined to believe, is capable of combining
    directly with more oxygen than exists in potash, than with the
    oxymuriatic acid which, as far as is known, has no affinity for
    that substance.”

It is perfectly true, as Davy surmised, that potassium can combine with
more oxygen than is contained in potash, but it is no less true, as he
himself proved by his discovery of the so-called _euchlorine_, that
chlorine can combine with oxygen. Although he made several attempts
to isolate Mr. Chenevix’s hyper-oxygenised muriatic acid, he was
not successful at the time, and was evidently disposed to doubt its
separate existence.

The remaining portion of the paper, although of interest as
exemplifying Davy’s power of dealing with the broad issues which
his views raise, need not detain us now. He seizes the opportunity,
however, to correct his statements with regard to the presumed compound
nature of sulphur and phosphorus, and gives details of observations,
some of which, as in other of his papers, have been “discovered” by
subsequent observers. Thus he states:--

    “I have never been able to burn sulphur in oxygen without forming
    sulphuric acid in small quantities; but in several experiments
    I have obtained from 92 to 98 parts of sulphurous acid from 100
    of oxygen in volume; from which I am inclined to believe that
    sulphurous acid consists of sulphur dissolved in an equal volume
    of oxygen.”

It was hardly to be expected that views so entirely opposed to
the convictions of chemists at the time should pass unchallenged.
Berzelius, the countryman of Scheele, warmly defended the doctrine
of the French School, and yet another Scotch professor sought to show
that Davy was still “vera troublesome.” The controversy, in which Davy
himself took little part, occasioned considerable stir at the period,
and was even of interest outside philosophical circles. The discussion
was not without its uses, inasmuch as it led to fresh discoveries.
The noise of it all, however, is now forgotten. Berzelius eventually
enjoined his cook to speak no longer of oxymuriatic acid: “Thou must
call it _chlorine_, Anna; that is better.” Dr. Murray, with the
pertinacity of his race, still clung to the old doctrine, and defended
it with no little dialectical subtlety, but he alone was faithful among
the faithless. It is true there has been an occasional flutter in the
dovecots since these times, and the faith of chemists in the validity
of Davy’s teaching has been once or twice assailed, but as yet it has
survived all assaults.

The Royal Institution possesses a book which no lover of science
can regard with other than reverential interest. It is a small,
well-bound quarto of some 386 manuscript pages, of notes taken by
Michael Faraday, when a bookbinder’s apprentice, of the last of Davy’s
lectures at the Institution. A Mr. Dance--his name deserves to be held
in remembrance--had given the youth a ticket for the lectures, and
Faraday, perched in the gallery over the clock, had zealously followed
the expositions of the brilliant lecturer, and had subsequently, when
asking for an engagement at the Institution, sent in these notes,
neatly written out and embellished with drawings of the apparatus, to
the Professor as evidence of the applicant’s “knowledge, diligence and
order.” Among the lectures is one on chlorine, given on March 14th,
1812, the notes of which are as characteristic of the auditor as of the
lecturer. We read:--

    “Accustomed for years to consider the chemical principles of the
    French School of Physical Sciences as correct, I had adopted
    them and put faith in them until they became prejudices, and I
    even felt unwilling to give them up when my judgment was fully
    convinced by experiment that they were erroneous. I know that
    this is the case in some degree with almost every person; he is
    unwilling to believe that he is wrong and therefore feels averse
    to adopt what is right when it opposes his principles.”

Then follows an account of various experiments showing the properties
of chlorine, and the proofs that it contains no oxygen:--

    “Oxygen does combine with chlorine. I have ventured to name
    the compound _euchlorine_; it is of a very bright yellow-green
    colour. Names should represent things not opinions for in the
    last case they often tend to misrepresent and mislead.

    “Had Mr. Berthollet obtained oxygen from chlorine there would
    have been no error in his theory, but by not attending to the
    minute circumstances of his experiment, by not ascertaining that
    the water present acted no part and was not decomposed he fell
    into an error, and of course all the conclusions he drew were
    false and erroneous. Nothing should be allowed but what can be
    proved by experiment, and nothing should be taken for granted
    upon analogy or supposition.”

Faraday concludes as follows:--

    “Mr. Davy now proceeded to comment and make observations on the
    former theory of chlorine gas. Here I was unable to follow him.
    The plan which I pursue in taking of notes is convenient and
    self-sufficient with respect to the theoretical and also the
    practical part of the lecture, but for the embellishments and
    ornaments of it it will not answer. Mr. Davy’s language at those
    times is so superior (and indeed throughout the whole course
    of the lecture) that then I am infinitely below him, and am
    incapable of following him even in an humble style. Therefore I
    shall not attempt it; it will be sufficient to give a kind of
    contents of it. He said that hypotheses should not be considered
    as facts and built upon accordingly. Nevertheless, if cautiously
    pursued, they might lead to mature fruit. That nothing should
    be taken for granted unless proved. By considering oxygen as
    contained in chlorine the whole chemical world had been wrapped
    in error respecting that body for more than one-third of a
    century.

    “He noticed that all the truly great scientific men were
    possessed of great humility and diffidence of their own opinions
    and powers. He spoke of Scheele, the discoverer of chlorine;
    observed that he possessed a truly philosophical spirit, gave
    up his opinions when he supposed them to be erroneous, and
    without hesitation or reluctance adopted those of others which he
    considered more correct; admired his spirit and recommended it to
    all philosophers; compared it to corn, which looked but simple
    and insignificant in blossom, and asked for little praise, yet
    was the support of man.”

In his fifth Bakerian lecture, “On some of the Combinations of
Oxymuriatic Gas and Oxygene, and on the chemical Relations of these
Principles to inflammable Bodies,” read before the Royal Society on
November 15th, 1810, he still further developed his ideas respecting
the nature of chlorine. Gay Lussac and Thenard, who had convinced
themselves that potassium and sodium are not hydrates of potash and
soda, had made known the fact that potassium can combine with oxygen
in more than one proportion; and Davy had confirmed their conclusion,
seeing in it a further proof of his views concerning the constitution
of the hyper-oxymuriate of potash. He then studied the behaviour of
a large number of the metals and their oxides with chlorine, making
in many cases quantitative determinations, from which very fair
approximations to the combining proportions or atomic weights of the
substances may be deduced. Thus, he says “the number representing the
proportion in which mercury combines must be about 200,” and that “the
quantity of chlorine in corrosive sublimate is exactly double that in
calomel, and that the orange oxide contains twice as much oxygen as the
black, the mercury being considered the same in all.” The atomic weight
of silver deducible from the amount of chlorine taken up by that metal
during its conversion into horn-silver is almost exactly the value
obtained by the most rigorous analyses of modern times. It is, however,
noteworthy that in this paper Davy is brought into sharp conflict
with Dalton, and there is a characteristic exhibition of temper in
the way in which he protests against the manner in which Dalton had
sought to use certain of his numerical estimations in deducing the
weights of atoms. The comparative merits of Mr. Higgins and John
Dalton as the real authors of the explanation of the laws of chemical
combination have now been fully and finally assessed, but it was wholly
unnecessary for the purpose of Davy’s contention to underrate the
originality of the Manchester chemist. Dalton was no doubt wrong in the
assumption that 47 represented the weight of the atom of nitrogen, and
Davy was right in pointing out the invalidity of the basis on which
this assumption rested, and in his statement that 13·4 more nearly
represented the smallest proportion in which nitrogen is known to
combine. Davy says:--

    “I shall enter no further at present into an examination of the
    opinions, results, and conclusions of my learned friend; I am
    however obliged to dissent from most of them, and to protest
    against the interpretations that he has been pleased to make of
    my experiments; and I trust to his judgment and candour for a
    correction of his views.

    “It is impossible not to admire the ingenuity and talent with
    which Mr. Dalton has arranged, combined, weighed, measured, and
    figured his atoms; but it is not, I conceive, on any speculations
    upon the ultimate particles of matter, that the true theory of
    definite proportions must ultimately rest. It has a surer basis
    in the mutual decomposition of the neutral salts, observed by
    Richter and Guyton de Morveau, in the mutual decompositions of
    the compounds of hydrogen and nitrogen, of nitrogen and oxygen,
    of water and the oxymuriatic compounds; in the multiples of
    oxygen in the nitrous compounds; and those of acids in salts,
    observed by Drs. Wollaston and Thomson; and above all, in the
    decompositions by the Voltaic apparatus, where oxygen and
    hydrogen, oxygen and inflammable bodies, acids and alkalies, &c.,
    must separate in uniform ratios.”

It has been alleged that Davy in thus expressing himself offered a
kind of factious opposition to the views of Dalton. In so far as they
were _atomic_, this is possibly true, for Davy never brought himself
to regard the fact of chemical combination occurring in definite
proportions as admitting of the simple mechanical explanation of
Dalton, which he considered too speculative. That, however, he did
ample justice to Dalton’s merits ultimately will be seen from the terms
in which he speaks of them on the occasion of the award to Dalton
in 1826 of the first of the Royal medals. In one of his unfinished
Dialogues, written shortly before his death, “On the Powers which act
upon Matter and produce Chemical Changes,” he thus expresses himself:--

    “The atomic doctrine, or theory, has been embraced by several
    modern chemists; but the development of it is owing to Mr. Dalton
    who seems to have been the first person to generalize the facts,
    of chemistry relating to definite proportions.... Mr. W. Higgins
    appears to have had only some loose idea of particles combining
    with particles, without any profound views of the quantity being
    unalterable; and there is good reason for thinking that these
    ideas, as he expresses them, were gained from another source,
    Dr. Bryan Higgins, who many years before supported the notion,
    that chemical substances were formed of molecules, either simple
    or compound, surrounded by an atmosphere of heat; and his views,
    though not developed with precision, approached nearer to those
    of Mr. Dalton, than those of his cousin. But neither of these
    gentlemen attempted any statical expressions; and to Richter and
    Dalton belongs the exclusive merit of having made the doctrine
    practicable. As a theoretical view, other authors have a claim to
    it, and the early followers of Newton, such as Kiel, Hartley, and
    Marzucchi, all attempted a corpuscular chemistry, founded upon
    figure, weight, and attractive power of the ultimate particles
    of matter; but this chemistry was of no real use, and had no
    other foundation than in the imagination. Indeed, in my opinion,
    Mr. Dalton is too much of an _Atomic Philosopher_; and in making
    atoms arrange themselves according to his own hypothesis, he has
    often indulged in vain speculation; and the essential and truly
    useful part of his doctrine, the expression of the quantities
    in which bodies combine, is perfectly independent of any views
    respecting the ultimate nature either of matter or its elements.”

He concludes the paper in which he so minutely studied the action of
chlorine upon oxides by asking, if it be said that the oxygen arises
from the decomposition of the oxymuriatic gas and not from the oxides,
why is it always the quantity contained in the oxide that is evolved?
And why in some cases, as those of the peroxides of potassium and
sodium, it bears no relation to the quantity of oxymuriatic gas?

    “When potassium is burnt in oxymuriatic gas, a dry compound is
    obtained. If potassium combined with oxygen is employed, the
    whole of the oxygen is expelled, and the same compound formed. It
    is contrary to sound logic to say, that this exact quantity of
    oxygen is given off from a body not known to be compound, when we
    are certain of its existence in another; and all the cases are
    parallel.”

An argument in favour of the existence of oxygen in chlorine might be
derived from the circumstance of the formation of the latter gas by
the action of muriatic acid on peroxides. Davy found that, by heating
muriatic acid gas in contact with dry peroxide of manganese, water was
rapidly formed and oxymuriatic gas produced.

    “Now as muriatic acid gas is known to consist of oxymuriatic
    gas and hydrogen, there is no simple explanation of the result,
    except by saying that the hydrogen of the muriatic acid combined
    with oxygen from the peroxide to produce water.”

The bleaching power of chlorine had been explained by Scheele on the
supposition that it destroyed colours by combining with phlogiston.
Berthollet considered it to act by supplying oxygen. Davy then made
the well-known experiment proving that the dry gas “is incapable of
altering vegetable colours, and that its operation in bleaching depends
entirely upon its property of decomposing water and liberating its
oxygen.” It had been supposed that oxymuriatic acid gas was capable of
being condensed and crystallised at a low temperature. He shows that
it was only damp chlorine or its solution in water that yielded any
solid product. He exposed the pure gas, dried by muriate of lime, to a
temperature of -40° F., without observing any change. It is curious,
however, that liquid chlorine had actually been obtained by Northmore
five years before by heating the so-called hydrate of chlorine under
pressure. The phenomenon was misunderstood, and it was reserved for
Faraday, in 1823, to show that the product was actually the liquefied
gas.

Davy, who was not always happy in his suggestions as to chemical
nomenclature, proposed to denote the compounds of oxymuriatic gas by
the names of their bases with the termination _ane_.

    “Thus, argentane may signify horn-silver; stannane Libavius’s
    liquor; antimonane, butter of antimony; sulphurane, Dr. Thomson’s
    sulphuretted liquor, and so on for the rest.... In cases when
    two or more proportions of inflammable matter combine with one
    of gas; or two or more of gas with one of inflammable matter, it
    may be convenient to signify the proportions by affixing vowels
    before the name, when the inflammable matter predominates, and
    after the name when the gas is in excess; and in the order of the
    alphabet, _a_ signifying two, _e_, three, _i_, four and so on.”

Thus he called phosphorus pentachloride _phosphorana_, and the
trichloride _phosphorane_, because there was a larger percentage
proportion of phosphorus in the latter compound than in the former.
That Davy was not unaware of the difficulties and inconveniences of
such a system of nomenclature may be inferred from what he says in his
“Elements” concerning the names for the two chlorides of mercury, the
true composition of which he was the first to discover:--

    “The names _mercurane_ and _mercurana_ which may be adopted to
    signify the relations of their composition, are too similar to
    each other to be safely used as familiar appellations for the two
    substances, as corrosive sublimate is a powerful poison, calomel
    an excellent medicine.”

In matters of chemical nomenclature Davy was a great latitudinarian.
All that he contended for was that names should be independent of all
speculative views, and should rather be derived from some simple and
invariable property. It is remarkable, however, that he who invented
the happy term “chlorine” should have objected to the word “cyanogen.”
At the close of the short paper “On the Prussic Basis and Acid,” in
which he first made known the existence of the cyanides of phosphorus
and of iodine, he said:--

    “I wish M. Gay Lussac could be prevailed upon to give up the
    inexpressive and difficult names of cyanogen and hydrocyanic
    acid, and to adopt the simple ones of prussic gas and prussic
    acid.”

By treating the potassium hyper-oxymuriate of Berthollet (potassium
chlorate) with hydrochloric acid, a greenish-yellow explosive gas is
obtained which Chenevix had referred to as “hyper-oxygenised muriatic
acid,” and as indicating the existence of a compound of oxymuriatic gas
and oxygen in a separate state. Davy, as we have seen, was at first
inclined to doubt the existence of this substance, and to consider the
gas as simply chlorine. But on comparing it with chlorine prepared in
other ways he perceived a difference; its solution in water was of
lemon yellow or orange colour; when treated with mercury it becomes of
a brilliant yellow green. It is, moreover, highly explosive, especially
when heated, even at the warmth of the hand, when it loses its vivid
colour, and is resolved into a mixture of oxygen and chlorine. Metals,
arsenic, phosphorus, charcoal, nitric oxide, act upon it in a manner
different from that of chlorine. Davy makes use of these differences as
a proof of the correctness of his views of the nature of chlorine.

    “If the power of bodies to burn in oxymuriatic gas depended upon
    the presence of oxygen, they all ought to burn with much more
    energy in the new compound; but copper and antimony, and mercury
    and arsenic and iron and sulphur have no action upon it, till
    it is decomposed; and they act then according to their relative
    attractions on the oxygen, or on the oxymuriatic gas. There is a
    simple experiment which illustrates this idea. Let a glass vessel
    containing brass foil be exhausted, and the new gas admitted, no
    action will take place; throw in a little nitrous gas [nitric
    oxide], a rapid decomposition occurs, and the metal burns with
    great brilliancy.

    “As the new compound in its purest form is possessed of a
    bright yellow-green colour, it may be expedient to designate it
    by a name expressive of this circumstance and its relation to
    oxymuriatic gas. As I have named that elastic fluid Chlorine; so
    I venture to propose for this substance the name Euchlorine, or
    Euchloric gas from ευ and χλωρος. The point of nomenclature I am
    not inclined to dwell upon. I shall be content to adopt any name
    that may be considered as most appropriate by the able chemical
    philosophers attached to this Society” [the Royal Society].

Euchlorine was subsequently discovered by Soubeiran to be a mixture of
chlorine and chlorine peroxide, a gas which Davy himself afterwards
isolated in a pure state. It is however obvious from the accounts he
gives that even in his first paper he must have been experimenting
with a fairly pure product, due probably to the circumstance that he
had collected the mixed gases over mercury, which retains the greater
part of the chlorine. Former experimenters had collected the gas over
water, which dissolves the chlorine peroxide more readily than the
chlorine. Madame de Staël once observed that an interesting book might
be written on the important consequences which have sprung from little
differences. It ought to be noted, however, that Davy had himself
doubts whether his euchlorine was not a mixture of chlorine and the gas
which he subsequently discovered, and to which he says: “I shall not
propose to give any name till it is determined whether euchlorine is a
mixture or a definite compound.”

It has been stated that Davy discovered the two chlorides of
phosphorus. In a paper read to the Royal Society on June 18th, 1812,
“On some Combinations of Phosphorus and Sulphur and on some other
Subjects of Chemical Inquiry,” he reverts to these substances, as
they “offer decided evidences in favour of an idea that has been for
some time prevalent among many enlightened chemists and which I have
defended in former papers published in the Philosophical Transactions;
namely that bodies unite in definite proportions, and that there is a
relation between the quantities in which the same element unites with
different elements.”

He first makes a determination, singularly accurate for the time, of
the amount of chlorine contained in the lower chloride, and finds
that 13·6 grains on decomposition with water afforded 43 grains of
horn-silver; theory requires 42·6 grains. By synthetical experiments
he came to the conclusion that the amount of chlorine absorbed by
phosphorus to form the higher chloride was exactly double that
contained in the lower chloride: he found that 3 grains of phosphorus
combined with 20 grains of chlorine: in reality it should require only
17¾ grains.

He shows that by treatment with water the lower chloride yields
_phosphorous acid_, the properties and mode of decomposition of which
by heat he accurately describes. He further concludes, as the logical
consequence of his view of the composition of the two chlorides,
and the mode of their decomposition by water, that phosphorous acid
contains half the amount of oxygen present in phosphoric acid, the
quantity of phosphorus being the same. It is noteworthy that in his
argument, as indeed on all subsequent occasions when he speaks of the
decomposition of water in definite proportions, he regards water as
composed of 2 combining proportions of hydrogen and 1 of oxygen, and
the number representing it as 17, oxygen being regarded as 15. Certain
of his statements considered in the light of subsequent work are
interesting. Thus he says:--

    “A solid acid volatile at a moderate degree of heat, may be
    produced by burning phosphorus in very rare air, and this seems
    to be phosphorous acid free from water; but some phosphoric acid,
    and some yellow oxide of phosphorus are always formed at the same
    time.”

He also observes that unless the product of the combustion of
phosphorus is strongly heated in oxygen it contains phosphorous acid
as well as phosphoric acid. He further states that sulphurous acid
(sulphur dioxide) consists of equal weights of oxygen and sulphur,
which is almost strictly true, and that sulphuretted hydrogen is
composed of 1 combining proportion of sulphur and 2 of hydrogen,
although his values for the combining proportions of sulphur and
oxygen are incorrect. He repeats Dalton’s experiment of the formation
of “solid sulphuric acid” by the mutual action of sulphur dioxide
and nitric oxide, and shows that the substance is only produced in
presence of vapour of water; the two substances, he says, then “form
a solid crystalline hydrate; which when thrown into water gives off
nitrous gas and forms a solution of sulphuric acid.” This substance is
the so-called “leaden-chamber crystal,” or nitrosulphonic acid, the
existence of which was first made known by Scheele.

Davy’s conclusions concerning the composition of the oxides and
chlorides of phosphorus were subsequently contested by Berzelius and
Dulong, who showed that although the amount of chlorine in the lower
chloride was identical with that which he had found, the ratio of this
amount to that in the higher chloride was as 3 to 5, and not as 1 to 2,
and that the same ratio held good as regards the oxygen in phosphorous
oxide and phosphoric oxide. Davy, six years afterwards, repeated
his experiments, but without discovering the fallacy in his first
observations.

       *       *       *       *       *

The other incidents in Davy’s scientific career may be most
conveniently dealt with in connection with his personal history.




CHAPTER VIII.

MARRIAGE--KNIGHTHOOD--ELEMENTS OF CHEMICAL PHILOSOPHY--NITROGEN
TRICHLORIDE--FLUORINE.


Davy was now (1810) thirty-two years of age, and near the summit of his
scientific fame, and perhaps also, says his brother John, who was then
in daily association with him, at the height of his happiness.

    “He had earned an unsullied and noble reputation; he was loved
    and admired by friends, who had cheered him on in his career;
    he had hardly passed the prime of manhood; he was in possession
    of excellent health; he had open to him almost every source of
    ordinary recreation and enjoyment; and he had, besides, the
    unfailing pleasures derived from the active and successful
    pursuit of science. His letters written at this time, [to his
    mother and sisters] strongly mark a happy contentment, as well as
    a very amiable and affectionate state of mind.”

His popularity at the Royal Institution was unbounded; indeed, he was
the very prop of its existence, and was so recognised. But honourable
as his position was, it brought him little more than a competency; and
however generously disposed the Managers might have felt towards him,
the financial circumstances of the Institution afforded no certainty
of a future independence. The Bishop of Durham and Sir Thomas Bernard
sought to induce him to enter the Church, in the hope that his talents
and eloquence would minister no less to the cause of religion than
to his own prospects of preferment. At this period he had serious
thoughts of again applying himself to the study of medicine, with a
view of practising as a physician, and he actually entered his name
at Cambridge and kept some terms there. But whether the unfortunate
experience of his colleagues Wollaston and Young deterred him, or
whether, as is more probable, Science had too strong a hold upon his
affections, it is certain he made no resolute attempt to abandon her.

Money was never an object with Davy, except as the means of procuring
him the advantages which the moneyed classes can command; had he
cared for it, his talents were a marketable commodity, and would have
brought him riches in many ways. The smiling goddess now showed him
one way as honourable as it was lucrative and pleasurable. The Dublin
Society invited him to lecture to them on the discoveries which had
made him famous, with the promise of a more substantial token of their
appreciation than the sound of their applause.

The following minutes from the Proceedings of the Society serve to
explain this:--

    “May 3, 1810. _Resolved_--That it is the wish of the Society
    to communicate to the Irish public in the most extended manner
    (consistent with the engagements of the Society), the knowledge
    of a science so intimately connected with the improvement of
    agriculture and the arts, which is their great object to promote;
    and that, with this view, it appears to them extremely desirable
    to obtain the fullest communication of the recent discoveries in
    electro-chemical science which have been made by Mr. Davy.

    “_Resolved_--That application be made to the Royal Society
    requesting that they be pleased to dispense with the engagements
    of Mr. Davy [as Secretary], so far as to allow the Dublin
    Society to solicit the favour of his delivering a course of
    electro-chemical lectures in their new laboratory, as soon as may
    be convenient after the present course of chemical lectures shall
    have been completed by their professor, Mr. Higgins.

    “_Resolved_--That the sum of 400 guineas be appropriated out
    of the funds of the Society, to be presented to Mr. Davy, as a
    remuneration, which they propose him to accept, and as a mark of
    the importance they attach to the communication they solicit.”

We further read: “Mr. Davy arrived in Dublin and delivered his course
of lectures to a crowded auditory.” At the close of his lectures the
following resolution was passed:--

    “November 29th, 1810. _Resolved_--That the thanks of the Society
    be communicated to Mr. Professor Davy, for the excellent course
    of lectures which, at their request, he has delivered in their
    new laboratory; and to assure him, that the views which led the
    Society to seek for these communications have been answered even
    beyond their hopes; that the manner in which he has unfolded his
    discoveries has not only imparted new and valuable information,
    but, further, appears to have given a direction of the public
    mind towards chemical and philosophical inquiries, which cannot
    fail in its consequences to produce the improvement of the
    sciences, arts, and manufactures in Ireland. That Mr. Davy be
    requested to accept the sum of five hundred guineas from the
    Society.”

From Mr. Hare’s “Life and Letters of Maria Edgeworth” we gain some
further information of the manner in which these lectures were
received. In a letter to her cousin, Miss Ruxton, Miss Edgeworth writes:

    “We are to set out for Dublin on the 13th [November] to hear
    Davy’s lectures.”

Mrs. Edgeworth adds:

    “We spent a few weeks in Dublin. Davy’s lectures not only opened
    a new world of knowledge to ourselves and to our young people,
    but were especially gratifying to Mr. Edgeworth and Maria,
    confirming, by the eloquence, ingenuity, and philosophy which
    they displayed, the high idea which they had so early formed of
    Mr. Davy’s powers.”

Additional evidence of his success is seen in the circumstance that the
Society decided to repeat their invitation:

    “June 13th, 1811. _Resolved_--That a letter be written to Mr.
    Professor Davy requesting him to favour the Dublin Society and
    the Irish public with a further communication of the recent
    discoveries in chemical philosophy, and to deliver a course of
    lectures in their laboratory for that purpose, in the months
    of November and December next; and requesting that he will
    also repeat to them, at the same time, the course of lectures
    in geological science which he has read this year to the Royal
    Institution; and that he will be so good as to procure for the
    Society copies of as many of the geological sketches referred
    to in that course as he may think necessary for the elucidation
    of the subject; and further requesting him to superintend the
    construction of a voltaic battery of large plates, for the use
    of the Society, to be transmitted to them in time for these
    lectures.”

We next read:

    “December 5th, 1811. _Resolved unanimously_--That the thanks of
    the Society be communicated to Mr. Davy, for the two excellent
    courses of lectures in chemical and geological science which,
    at their request, he has delivered in their laboratory, full of
    valuable information; and which have not merely continued, but
    materially increased, the spirit of philosophical research in
    Ireland.

    “_Resolved unanimously_--That Mr. Davy be requested to accept the
    sum of £750 as a remuneration on the part of the Society.”

On the occasion of his second visit Trinity College, Dublin, conferred
on him the degree of LL.D. It was the only mark of distinction he ever
received from any University. Before he gave his lectures he visited
Edgeworthstown, as we learn in a letter from Maria to Miss Ruxton:

    “Davy spent a day here last week, and was as usual full of
    entertainment and information of various kinds. He has gone to
    Connemara, I believe, to fish, for he is a little mad about
    fishing; and very ungrateful it is of me to say so, for he sent
    to us from Boyle the finest trout! and a trout of Davy’s catching
    is, I presume, worth ten trouts caught by vulgar mortals.”

To his mother he writes:

            “Ballina, Ireland, _October 24th_.

    “MY DEAR MOTHER,--I am safe and well, in a remote and beautiful
    part of Ireland, where I have been making an excursion with two
    of my friends. I shall return to Dublin in two or three days, and
    shall be very glad to hear from you or my sisters there. I hope
    you are all well and happy.

    “I heard from John a few days ago; he was quite well and in good
    spirits.

    “The laboratory in Dublin, which has been enlarged so as to hold
    550 people, will not hold half the persons who desire to attend
    my lectures. The 550 tickets issued for the course by the Dublin
    Society, at two guineas each, were all disposed of the first
    week; and I am told now that from ten to twenty guineas are
    offered for a ticket.

    “This is merely for your eye; it may please you to know that your
    son is not unpopular or useless. Every person here, from the
    highest to the lowest, shows me every attention and kindness.

    “I shall come to see you as soon as I can. I hear with infinite
    delight of your health, and I hope Heaven will continue to
    preserve and bless a mother who deserves so well of her children.

            “I am your very affectionate son
                                     “H. DAVY.

    “My kindest love to my sisters and aunts.”

But Davy’s affections at the moment were not wholly spent upon his
kindred, and another mistress than Science had become the object of
his devotion. The “little madness” of which Maria Edgeworth wrote was
always a vulnerable point with Davy, for he followed the calling of the
Apostles with all the zeal and ardour he gave to philosophy, and to
engage him upon the subject of angling was a more direct road to his
sympathies than to talk to him of science.

The wooing began in this wise:

    “Mr. Davy regrets that he cannot send Walton to Mrs. Apreece
    this morning. He did not recollect that he had lent the book to
    a friend who lives a little way out of town. He will send honest
    Isaac to Mrs. Apreece to-morrow or Thursday.

    “Mrs. Apreece is already of the true faith of the genuine angler,
    the object of whose art and contemplation is to exalt spirit
    above matter, to enable the mind to create its own enjoyments and
    to find society even in the bosom of Nature.”

Matters went on apace. Shortly afterwards we read:

    “I return the ticket. I begin to like the opera from association.
    The same association would, I think, make me love a desert, and
    perhaps, in a long time, might make me an admirer of routs.”

Again:

    “To avoid studiously what other people seek would have the
    semblance of affectation and though sincerely I have no ambition
    to shine in courts or to become a courtier; yet I have sympathy
    more than enough to wish to be where you like to go.”

On another occasion he wrote:

    “I find an invitation from Mr. T---- on my return last night for
    Wednesday. Pray do you go to the Miss Ch----’s to-night or to
    Miss S----’s to-morrow night? I wish to know as you are my magnet
    (though you differ from a magnet in having no repulsive point)
    and direct my course. Your society always delightful to me is
    really at this moment balm to a wounded mind.”

The following is a New Year’s Day letter written to arrive on January
1st, 1812:--

    “I hope the cold weather has not increased your indisposition and
    that the foggy sky has not made you melancholy. I trust you are
    now well and happy: I give myself pleasure by believing that you
    are.

    “I have a motive for writing this day besides that of doing what
    I like. I find that Friday the 10th is a Royal Society Club day
    and that I ought to dine with the Club. All other days are yours
    and _that_ shall be yours if you command it, but I know you wish
    me to do what I _ought_ to do, and you _now_ cannot doubt the
    exclusive nature of your influence and the absolute nature of
    your power.

    “I spent the last two days very pleasantly at Wilderness, Lord
    Camden’s; there was a very agreeable social party and a Christmas
    country ball: a fine park had lost its beauty from the old age
    of the year and everything was white; the circle round the fire
    had in consequence more charms and my friend and I left it this
    morning very well amused.

    “To-day we celebrate the old Mr. Children’s birthday who is 70.
    He bears his years healthfully and joyfully. Such winter’s days
    as his are rather to be desired than feared--sunny, calm and warm.

    “I hope, my darling friend, that you bear no uneasiness in your
    kind and good heart and that you give its true meaning to my
    unlucky sentence. Indeed I never in the whole course of our
    social converse ever intended to offend you or give you a moment
    of uneasiness and I do not think I should feel anything _long
    painful_ that I thought would promote your happiness even though
    it should require from me the greatest of all sacrifices. You
    know what this is and I trust you will never oblige me to make it.

    “I go on Thursday to a wild part of Kent to shoot pheasants: the
    house is Mr. Hodges, the post-town Cranbrook. I shall accompany
    Children to town on Sunday; and I hope you will permit me to see
    you that evening if I come in time, or Monday morning. I am going
    on steadily for three hours a day with Radiant Heat and Light. I
    might petition for one of your distant beams of light. You know
    it would delight me; but whether it comes or no you shall not
    cease to be my sun.”

These letters, with many others addressed by him to the lady, are now
before me. They had been carefully tied up and preserved, and are all
dated by her on the back--even down to the little missives sent across
from Albemarle Street to Berkeley Square, where she resided. From the
number and frequency of these it is evident that the porter suffered
from no lack of exercise. After her death in 1855 these letters came
into the possession of Dr. John Davy, together with other papers, and
some have been published already in his “Fragmentary Remains.” The
correspondence is of especial interest from the sidelight it throws on
Davy’s disposition and character. Many of the letters are delightful
in tone and feeling; not even Amadis de Gaul, that cream and flower of
gentility, or that mirror of chivalry, the Knight of the Woful Figure,
could have been more courteous in bearing, or have shown a warmer and
at the same time a more deferential admiration of the lady he wooed.
But the world, after all, has no concern with their tender confidences.
It is sufficient to say that Davy’s letters are such as might be
expected from his ardent temperament and active imagination; from his
love of natural scenery, his faculty of happy expression, and graphic
power of description.

Early in 1812 Sir Joseph Banks, whose constant thought was of and for
the Royal Society, thus wrote to his friend Sir George Stanton:--

    “The Royal Society has been well supplied with papers, and
    continues to be so. Davy, our secretary, is said to be on the
    point of marrying a rich and handsome widow, who has fallen in
    love with Science and marries him in order to obtain a footing
    in the Academic Groves; her name is Apreece, the daughter of Mr.
    Carr, [Kerr] who made a fortune in India, and the niece of Dr.
    Carr, [Kerr] of Northampton. If this takes place, it will give
    to science a kind of new _éclat_; we want nothing so much as the
    countenance of the ladies to increase our popularity.”

The lady was the widow of Shuckburgh Ashby Apreece, the eldest son of
Sir Thomas Apreece; she was the daughter and heiress of Charles Kerr of
Kelso, who had been secretary to Lord Rodney, and had made a fortune in
the West Indies. She was also a “far-away cousin” of Sir Walter Scott,
and on the occasion of his tour in the Hebrides with his family, “his
dear friend and distant relation,” as he calls her, accompanied them.
She had been, he says, “a lioness of the first magnitude in Edinburgh”
during the preceding winter; and in one of his letters to Byron in
1812, inviting him to Abbotsford, he mentions as one of the visitors
that would make his house attractive “the fair or shall I say the sage
Apreece that was, Lady Davy that is, who is soon to show us how much
science she leads captive in Sir Humphry; so your lordship sees, as
the citizen’s wife says in the farce, ‘Threadneedle Street has some
charms,’ since they procure us such celebrated visitants.” How Scott
regarded her is further indicated in the letters which he addressed to
her on the occasion of his son’s marriage, and during the financial
crash which overwhelmed him.

When the marriage was arranged Davy thus wrote to his mother:--

    “MY DEAR MOTHER,--You possibly may have heard reports of my
    intended marriage. Till within the last few days it was mere
    report. It is I trust now a settled arrangement. I am the
    happiest of men, in the hope of a union with a woman equally
    distinguished for virtues, talents and accomplishments....

    “You, I am sure, will sympathise in my happiness. I believe I
    should never have married, but for this charming woman, whose
    views and whose tastes coincide with my own, and who is eminently
    qualified to promote my best efforts and objects in life....

            “I am your affectionate son,
                                “H. DAVY.”

In the following letter to Dr. John Davy, who was then in Edinburgh as
a student of medicine, we have also the announcement of another event:--

            “Friday, _April 10th, 1812_.

    “MY DEAR BROTHER,--You will have excused me for not writing to
    you on subjects of science. I have been absorbed by arrangements
    on which the happiness of my future life depends. Before you
    receive this these arrangements will, I trust, be settled; and,
    in a few weeks, I shall be able to return to my habits of study
    and of scientific research.

    “I am going to be married to-morrow; and I have a fair prospect
    of happiness, with the most amiable and intellectual woman I have
    ever known.

    “The Prince Regent, unsolicited by me, or by any of my intimate
    friends, was pleased to confer the honour of knighthood on me at
    the last _levée_. This distinction has not often been bestowed on
    scientific men; but I am proud of it, as the greatest of human
    geniuses bore it; and it is at least a proof that the court has
    not overlooked my humble efforts in the cause of science.

    “I have discovered pure phosphorous acid (a solid body, very
    volatile); and a pure hydro-phosphorous acid, containing
    two proportions of water and four of phosphorous acid, and
    decomposing by heat into phosphoric acid and a new gas containing
    four proportions of hydrogen and one of phosphorus....

    “Pray address to me Sir H. Davy, Beechwood Park, near Market St.
    Alban’s.

    “Believe me, my dear John, I shall always take the warmest
    interest in your welfare and happiness, and will do everything to
    promote your views. I shall have some ideas on your studies soon
    to communicate.

            “I am, my dear brother most affectionately yours
                                                    “H. DAVY.”

He was knighted by the Prince Regent at a _levée_ held at Carlton House
on the 8th April, 1812, being the first person on whom that honour was
conferred by the Regent. On the following day he delivered his farewell
lecture as Professor of Chemistry at the Royal Institution. It was on
the Metals, and a report of it is contained in Faraday’s manuscript
notes before referred to. Faraday says:--

    “Having thus given the general character of the metals, Sir H.
    Davy proceeded to make a few observations on the connection
    of science with the other parts of polished and social life.
    Here it would be improper for me to follow him. I should merely
    injure and destroy the beautiful, the sublime observations
    that fell from his lips. He spoke in the most energetic and
    luminous manner of the advancement of the arts and sciences, of
    the connection that had always existed between them and other
    parts of a nation’s economy. He noticed the peculiar congeries
    of great men in all departments of life that generally appeared
    together, noticed Anaximander, Anaximenes, Socrates, Newton,
    Bacon, Elizabeth, etc., but, by an unaccountable omission, forgot
    himself, though I venture to say no one else present did.

    “During the whole of these observations his delivery was easy,
    his diction elegant, his tone good, and his sentiments sublime.”

Two days afterwards he was married, and Lady Davy and he passed most
of the spring and summer in the North of England and in Scotland,
on a round of visits, cultivating those patrician instincts and
susceptibilities to the charms of rank that his new station served to
accentuate.

Writing to Miss Margaret Ruxton, Maria Edgeworth says:--

    “I suppose you have heard various _jeux d’esprit_ on the marriage
    of Sir Humphry Davy and Mrs. Apreece? I scarcely think any of
    them worth copying.”

But she gives the following:--

    “Too many men have often seen
      Their talents underrated;
    But Davy owns that his have been
      Duly _Apreeciated_.”

Shortly after his wedding he wrote to his brother John:--

    “I communicated to you in a former letter, my plans, as they
    were matured. I have neither given up the Institution, nor am I
    going to France; and, wherever I am, I shall continue to labour
    in the cause of science with a zeal not diminished by increase of
    happiness and (with respect to the world) increased independence.

    “I have just finished the first part of my ‘Chemistry’ to my
    own satisfaction, and I am going to publish my ‘Agricultural
    Lectures’ for which I am to get 1,000 guineas for the copyright
    and 50 guineas for each edition, which seems a fair price....

    “I was appointed Professor (honorary) to the Institution, at the
    last meeting. I do not pledge myself to give lectures.... If
    I lecture it will be on some new series of discoveries, should
    it be my fortune to make them; and I give up the _routine_ of
    lecturing, merely that I may have more time to pursue original
    inquiries, and forward more the great objects of science. This
    has been for some time my intention, and it has been hastened by
    my marriage.

    “I shall have great pleasure in making you acquainted with Lady
    D. She is a noble creature (if I may be permitted so to speak
    of a wife), and every day adds to my contentment by the powers
    of her understanding, and her amiable and delightful tones of
    feeling.”

The allusion to the Institution is thus more circumstantially dealt
with in the following Minutes of the Meetings of the Managers:--

    “_May 11, 1812._ Mr. Hatchett reported that Sir H. Davy, though
    he cannot pledge himself to deliver lectures, will be willing to
    accept the offices of Professor of Chemistry and Director of the
    Laboratory and Mineralogical Collection without salary.”

Following which we read--

    “That the Managers hear with great regret the notification which
    they have just received that Sir H. Davy cannot pledge himself
    to continue the lectures which he has been accustomed to deliver
    with so much honour to the Institution and advantage to the
    public; but at the same time, they congratulate themselves on the
    liberal offer which Sir Humphry Davy has made to superintend the
    chemical department, and to assist and advise any lecturer the
    Managers may be pleased to appoint.”

The Managers thereupon ordered a special general meeting to nominate
him Professor of Chemistry, and he was elected on June 1st. How
necessary Davy was to the very existence of the Institution may be
gleaned from the fact that the balance in its favour at the end of the
year was £3 9s. 11d.

The “Chemistry” above referred to is his “Elements of Chemical
Philosophy,” which was published a few months after his marriage, with
a dedication to Lady Davy. She is asked to receive it as a proof of
his ardent affection, which must be unalterable, as it is founded upon
the admiration of her moral and intellectual qualities. The work was
begun in the autumn of 1811, and was composed with great rapidity, the
“copy” being sent to the press as it left his pen. The introductory
part on the History of Chemistry, and that on the General Laws of
Chemical Changes and on Radiant or Ethereal Matter, and probably some
other portions, are either transcripts or amplifications of his Royal
Institution lectures. Other sections are avowedly based upon his own
work as published in the _Philosophical Transactions_. Indeed, it was
remarked by a critic that the work could never be completed upon the
plan on which it was commenced, which was little less than a system of
chemistry in which all the facts were to be verified by the author.

Thomas Young, his former colleague at the Royal Institution, in the
_Quarterly Review_ for September, 1812, thus speaks of it:--

    “With all its excellencies this work must be allowed to bear
    no inconsiderable marks of haste, and we would easily have
    conjectured, even if the author had not expressly told us so
    in his dedication, that the period employed on it has been the
    ‘happiest of his life’....

    “The style and manner of this work are nearly the same with
    those of the author’s lectures delivered in the theatre of the
    Royal Institution. They have been much admired by some of the
    most competent judges of good language and good taste, and it
    has been remarked that Davy was born a poet, and has only become
    a chemist by accident. Certainly the situation in which he was
    placed induced him to cultivate an ornamented and popular style
    of expression and embellishment, and what was encouraged by
    temporary motives has become natural to him from habit. Hence
    have arisen a multitude of sentimental reflections and appeals
    to the feelings, which many will think beauties and some only
    prettinesses; nor is it necessary for us to decide in which of
    the two classes of readers we wish ourselves to be arranged,
    conceiving that in matters so indifferent to the immediate object
    of the work a great latitude may be allowed to the diversity of
    taste and opinion.”

Despite its egoism and the obvious marks of haste and imperfection it
displays, the work may still be read with interest by the chemical
student. We would recommend him before perusing it to study Dalton’s
“New System of Chemical Philosophy,” and he will gain a vivid
impression of the extraordinary strides which the science had made
during the four years which intervened between the publication of these
memorable books. Each work, too, is strongly typical of its author, and
reflects in the most striking manner the range and limitations of his
powers and the characteristics of his genius.

Towards the middle of October Davy returned to town. In a letter
written to his friend Children, from Edinburgh, he says:--

    “I have received a very interesting letter from Ampère. He says
    that a combination of chlorine and azote has been discovered at
    Paris, which is a fluid, and explodes by the heat of the hand;
    the discovery of which cost an eye and a finger to the author.
    He gives no details as to the mode of combining them. I have
    tried in my little apparatus with ammonia cooled very low, and
    chlorine, but without success.”

The substance here referred to is nitrogen chloride, one of the most
formidable explosives known to chemists, and which seriously maimed
Dulong, its discoverer, as stated. The “little apparatus” refers to a
portable chemical chest which accompanied Davy on all his travels.
Any new combination of nitrogen was certain to attract his immediate
attention. He seems to have remained to the last convinced that
nitrogen would turn out to be a non-elementary substance, and it is
remarkable how eagerly he caught at any hint or surmise which appeared
likely to afford support to his conjecture. He at once repeated
Dulong’s experiments in Children’s laboratory at Tunbridge, and
succeeded in obtaining considerable information concerning the chemical
and physical properties of this extraordinary substance, when he was
wounded in the eye by its explosion.

He thus breaks the news of his accident to Lady Davy:--

    “... Yesterday I began some new experiments to which a very
    interesting discovery and a slight accident put an end. I made
    use of a compound more powerful than gunpowder destined perhaps
    at some time to change the nature of war and influence the
    state of society. An explosion took place which has done me no
    other harm than that of preventing me from working this day
    [Sunday] and the effects of which will be gone to-morrow and
    which I should not mention at all, except that you may hear some
    foolish exaggerated account of it, for it really is not worth
    mentioning....”

In reality the accident was more serious than he would have Lady Davy
believe, and the injury prevented him from resuming his work for some
time.

In a letter written about the middle of January, 1813, from Wimpole,
where he was staying with Lord Hardwicke, he says:--

    “I have had another severe attack of inflammation in the eye,
    and was obliged to have the conjunctiva and cornea punctured. I
    suspect the cause was some little imperceptible fragment. I am
    just recovering, and hope I shall see as well soon as with the
    other eye.”

In the following April he was sufficiently recovered to resume the
study of Dulong’s compound, and in a letter to Sir Joseph Banks, dated
June 20th, 1813, and subsequently published in the _Philosophical
Transactions_, he gives a number of details concerning its nature
and composition. He accurately determined its specific gravity--viz.
1·653--but although he made a number of determinations of the amounts
of its constituents by various methods, his deduction that it consisted
of one proportion of nitrogen to four of chlorine was incorrect.
The experiments of Gattermann, made with great skill and courage,
have conclusively shown that the compound is, as long surmised, a
trichloride of nitrogen.

At about the same period, as we learn from a letter to his brother,
dated April 4th, 1813, he attacked the chemistry of fluorine:--

    “I am now quite recovered, and Jane [Lady Davy] is very well, and
    we have both enjoyed the last month in London. I have been hard
    at work. I have expelled fluorine from fluate of lead, fluate of
    silver, and fluate of soda by chlorine. It is a new acidifier,
    forming three powerful acids; hydrofluoric, silicated fluoric,
    and fluo-boric. It has the most intense energies of combination
    of any known body, instantly combining with all metals, and
    decomposing glass. Like the fabled waters of the Styx, it cannot
    be preserved, not even in the ape’s hoof. We have now a triad of
    supporters of combustion.”

The results of Davy’s work were communicated to the Royal Society on
July 8th, 1813. In his paper he states that M. Ampère of Paris had
furnished him with many ingenious and original arguments in favour of
the analogy between the muriatic and fluoric compounds, based partly
upon his (Davy’s) views of the nature of chlorine, and partly upon
reasonings drawn from the experiments of Gay Lussac and Thenard.
After a short account of the main properties of the silicated fluoric
acid gas (silicon fluoride), discovered by Scheele, fluoric acid
(hydrofluoric acid), discovered by Scheele but first obtained pure by
Gay Lussac and Thenard, and fluoric acid (boron fluoride), discovered
by Gay Lussac and Thenard, he states that, on the hypothesis of M.
Ampère--

    “the silicated fluoric acid is conceived to consist of a peculiar
    undecompounded principle, analogous to chlorine and oxygen,
    united to the basis of silica, or _silicum_; the fluo-boric
    acid of the same principle united to boron; and the pure liquid
    fluoric acid as this principle united to hydrogen,”

He then seeks to put the hypothesis to the test of experiment by
combining fluoric acid with ammonia in a platinum apparatus; the white
solid substance he obtained--so-called fluate of ammonia--contained
no moisture, and hence he inferred that no water was present and that
therefore fluoric acid was free from oxygen. The inference was more
correct than the experiment warranted. He further found that the action
of potassium upon fluate of ammonia is precisely similar to its action
upon muriate of ammonia, when ammonia and hydrogen are disengaged and
muriate of potassa formed. He then attempted to electrolyse solutions
of hydrofluoric acid. He says:

    “I undertook the experiment of electrizing pure liquid fluoric
    acid, with considerable interest, as it seemed to offer the most
    probable method of ascertaining its real nature; but considerable
    difficulties occurred in executing the process. The liquid
    fluoric acid immediately destroys glass, and all animal and
    vegetable substances; it acts on all bodies containing metallic
    oxides; and I know of no substances which are not rapidly
    dissolved or decomposed by it except [certain] metals, charcoal,
    phosphorus, sulphur and certain combinations of chlorine.”

After various unsuccessful attempts to make tubes of sulphur and of the
chlorides of lead and copper, he succeeded

    “in boring a piece of horn-silver in such a manner that I was
    able to cement a platina wire into it by means of a spirit lamp,
    and by inverting this in a tray of platina filled with liquid
    fluoric acid, I contrived to submit the fluid to the agency of
    electricity.”

He found that the platina wire at the positive pole rapidly corroded,
and became covered with a chocolate powder, and what appeared by its
inflammability to be hydrogen separated at the negative pole. He tried
a number of other experiments with different vessels and various
electrodes, but with no better success.

He suffered great inconvenience from the fumes of hydrofluoric acid;
they acted vigorously on the nails, and produced a most painful
sensation when in contact with the eyes. The conclusion he drew from
his experiments was that fluoric acid is “composed of hydrogen, and a
substance as yet unknown in a separate form, possessed like oxygen and
chlorine, of the negative electrical energy, and hence determined to
the positive surface, and strongly attracted by metallic substances.”

He then attempted to isolate the fluoric principle by treating various
fluates in a platinum apparatus with chlorine gas, but although there
was evidence of decomposition and the platinum was violently acted
upon, he could obtain no new gaseous matter.

    “From the general tenour of the results that I have stated, it
    appears reasonable to conclude that there exists in the fluoric
    compounds a peculiar substance, possessed of strong attractions
    for metallic bodies and hydrogen, and which combined with certain
    inflammable bodies forms peculiar acids, and which in consequence
    of its strong affinities and high decomposing agencies, it will
    be very difficult to examine in a pure form, and for the sake of
    avoiding circumlocution, it may be denominated _fluorine_, a name
    suggested to me by M. Ampère.

    “It is easy to perceive in following the above theory, that all
    the ideas current in chemical authors respecting the fluoric
    combinations, must be changed. Fluor-spar, and other analogous
    substances, for instance, must be regarded as binary compounds of
    metals and fluorine.”

Davy’s views are now part of current chemical doctrine, and his
previsions as to the nature of fluorine and its extraordinary chemical
activity have been verified in the most striking manner by the
admirable investigations of Moissan.




CHAPTER IX.

DAVY AND FARADAY--IODINE.


The year 1813 is memorable in the history of the Royal Institution,
from the fact that Faraday’s long and honourable association with it
dates from that time. The circumstances which led to this connection
were subsequently stated by himself in the following letter to Dr.
Paris:--

            “Royal Institution, _Dec. 23rd, 1829_.

    “MY DEAR SIR,--You ask me to give you an account of my first
    introduction to Sir H. Davy, which I am very happy to do, as I
    think the circumstances will bear testimony to his goodness of
    heart.

    “When I was a bookseller’s apprentice, I was very fond of
    experiment and very averse to trade. It happened that a
    gentleman, a member of the Royal Institution, took me to hear
    some of Sir H. Davy’s last lectures in Albemarle Street. I took
    notes, and afterwards wrote them out more fairly in a quarto
    volume.

    “My desire to escape from trade, which I thought vicious and
    selfish, and to enter into the service of Science which I
    imagined made its pursuers amiable and liberal, induced me at
    last to take the bold and simple step of writing to Sir H. Davy,
    expressing my wishes, and a hope that, if an opportunity came in
    his way, he would favour my views; at the same time I sent the
    notes I had taken at his lectures.

    “The answer, which makes all the point of my communication, I
    send you in the original, requesting you to take great care of
    it, and to let me have it back, for you may imagine how much I
    value.

    “You will observe that this took place at the end of the year
    1812, and early in 1813 he requested to see me, and told me
    of the situation of assistant in the laboratory of the Royal
    Institution, then just vacant.

    “At the same time that he thus gratified my desires as to
    scientific employment, he still advised me not to give up the
    prospects I had before me, telling me that Science was a harsh
    mistress; and, in a pecuniary point of view, but poorly rewarding
    those who devoted themselves to her service. He smiled at my
    notion of the superior moral feelings of philosophic men, and
    said he would leave me to the experience of a few years to set me
    right on that matter.

    “Finally, through his good efforts I went to the Royal
    Institution early in March of 1813, as assistant in the
    laboratory; and in October of the same year went with him abroad
    as his assistant in experiments and in writing. I returned with
    him in April 1815, resumed my station in the Royal Institution,
    and have, as you know, ever since remained there.

            “I am, dear Sir, very truly yours
                                  “M. FARADAY.”

The answer which Faraday characteristically says makes all the point of
the foregoing communication is as follows:--

            “_December 24th, 1812._

    “SIR,--I am far from displeased with the proof you have given
    me of your confidence, and which displays great zeal, power of
    memory, and attention. I am obliged to go out of town, and shall
    not be settled in town till the end of January: I will then see
    you at any time you wish.

    “It would gratify me to be of any service to you. I wish it may
    be in my power.

            “I am, Sir, your obedient humble servant,
                                             “H. DAVY.”

The immediate cause of the connection was very trivial and commonplace.

Mr. W. Payne, whose name may be recalled in connection with Davy’s
memorandum respecting the state in which the Laboratory of the
Institution was kept, in the latter part of February, 1813, had a
disagreement with Mr. Newman, the instrument-maker, and so far forgot
himself as to strike that gentleman. Whereupon the Managers immediately
resolved that Mr. Payne should be dismissed from the Royal Institution,
and that a gratuity of £10 should be paid him in consideration of his
long services. Davy appears then to have called to mind the modest,
bright-eyed, active youth with the pleasant smile, who had expressed
his desire to devote himself to science.

In the minutes of the meeting of Managers on March 1st, 1813, we read--

    “Sir Humphry Davy has the honour to inform the Managers that he
    has found a person who is desirous to occupy the situation in the
    Institution lately filled by William Payne. His name is Michael
    Faraday. He is a youth of twenty-two years of age. As far as Sir
    H. Davy has been able to observe or ascertain, he appears well
    fitted for the situation. His habits seem good, his disposition
    active and cheerful, and his manner intelligent. He is willing to
    engage himself on the same terms as those given to Mr. Payne at
    the time of quitting the Institution.

    “_Resolved_--That Michael Faraday be engaged to fill the
    situation lately occupied by Mr. Payne on the same terms.”

In the minutes of the general monthly meeting of the members on April
5th, 1813, for putting in nomination from the chair the professors for
the year ensuing, we read:--

    “Sir H. Davy rose, and begged leave to resign his situation of
    Professor of Chemistry; but he by no means wished to give up
    his connection with the Royal Institution, as he should ever
    be happy to communicate his researches in the first instance
    to the Institution ..., and to do all in his power to promote
    the interest and success of this Institution. Sir H. Davy having
    retired, Earl Spencer moved That the thanks of this Meeting be
    returned to Sir H. Davy for the estimable services rendered by
    him to the Royal Institution. This motion was seconded by the
    Earl of Darnley, and, on being put, was carried unanimously.
    Earl Spencer further moved, That in order more strongly to mark
    the high sense entertained by this Meeting of the merits of Sir
    H. Davy, he be elected Honorary Professor of Chemistry; which,
    on being seconded by the Earl of Darnley, met with unanimous
    approbation.”

Mr. Brande was subsequently elected Professor.

During the autumn Davy obtained permission from Napoleon to pass
through France in the course of an extended tour on the Continent which
Lady Davy and he now projected. He thus announced his intention to his
mother:--

            “Andover, _Oct. 14, 1813_.

    “MY DEAR MOTHER,--We are just going to the Continent upon a
    journey of scientific inquiry which I hope will be pleasant to us
    and useful to the world. We go rapidly through France to Italy,
    and from there to Sicily; and we shall return through Germany.
    We have every assurance from the governments of the countries
    through which we pass, that we shall not be molested, but
    assisted. We shall stay probably a year or two....

    “As soon as I have settled a plan of correspondence abroad, I
    will write to you, and shall hear of you from John as often as
    possible. As I am permitted to pass through an enemy’s country,
    there must be no politics in any letters to me; and you had
    better not write except through the channel I shall hereafter
    point out....

    “When I return I shall peacefully fix my abode for life in my
    own country. Pray take care of Betsy. When the wind is cold she
    should not think of going out. Tell Grace not to be afraid,
    though I am going through France. My love to Kitty, and to Grace
    and Betsy. I am, my dear mother, wishing you all health and
    happiness, your very affectionate son

            “H. DAVY.”

On October 4th we find that he reported to the Managers that--

    “Michael Faraday had expressed a wish to accompany him on his
    scientific travels, but that he would not engage Mr. Faraday
    if the Professor of Chemistry considered his services as at
    all essential to the Institution, or if the Managers had the
    slightest objection to the measure.”

Mr. Brande reported that arrangements could be made to allow Mr.
Faraday to leave,

    “and that as he had shown considerable diligence and attention
    in cleaning and arranging the mineral collection he recommended
    his services to the Managers’ attention, as this was not his
    immediate duty.”

A few days afterwards the party, consisting of Sir H. and Lady Davy,
Mr. Faraday, and Lady Davy’s maid, together with the chemical cabinet,
crossed in a cartel from Plymouth to Morlaix. Here they were arrested,
but after a week’s detention, allowed to depart for Paris, where they
arrived on October 27th. Nothing could exceed the cordiality and
warmth of Davy’s reception by the French _savants_. On November 2nd he
attended a sitting of the First Class of the Institute, and was placed
on the right hand of the President, who announced to the meeting that
it was honoured by the presence of “Le Chevalier Davy.” Each day saw
some reception or entertainment in his honour. On November 10th he
dined with Rumford at Auteuil. How much had happened in the ten years
since last they met, and how different their situations now! Davy at
the very summit of his scientific eminence, courted and caressed by
society, honoured and admired by his intellectual peers; Rumford, his
former patron, a broken-hearted, disappointed man about to sink into
the grave, worried to death, in fact, by his wife, and the victim of
the spiteful persecutions she instigated. Of the remarkable men of
science whom Davy met on these occasions he has left us some slight
sketches composed during his last illness, some of which are of
interest to the student who desires to know something of the men whose
names are as household words in the history of chemistry. Guyton de
Morveau--who played such a leading part in the political Revolution
of France, as well as in the revolution of its chemistry, and who,
with Fourcroy, popularised the doctrines of Lavoisier whilst bringing
his head to the scaffold--was found to be a gentleman of mild and
conciliatory manners.

Vauquelin gave him the idea of the French chemists of another age,
belonging rather to the pharmaceutical laboratory than to the
philosophical one.

    “Nothing could be more singular than his manners, his life,
    and his _ménage_. Two old maiden ladies, Mdlles. de Fourcroy,
    sisters of the professor of that name, kept his house. I remember
    the first time that I entered it, I was ushered into a sort of
    bed-chamber, which likewise served as a drawing-room. One of
    these ladies was in bed, but employed in preparations for the
    kitchen; and was actually paring truffles.... Nothing could be
    more extraordinary than the simplicity of his conversation;--he
    had not the slightest tact, and even in the presence of young
    ladies, talked of subjects which, since the paradisaical times,
    never have been the objects of common conversation.”

    “CUVIER had even in his address and manner the character of a
    superior man;--much general power and eloquence in conversation,
    and a great variety of information on scientific as well as
    popular subjects. I should say of him, that he is the most
    distinguished man of _talents_ I have known; but I doubt if he is
    entitled to the appellation of a man of genius.”

    “HUMBOLDT was one of the most agreeable men I have ever known,
    social, modest, full of intelligence, with facilities of every
    kind: almost _too fluent_ in conversation. His travels display a
    spirit of enterprise. His works are monuments of the variety of
    his knowledge and resources.”

Of his great rival his comment is as follows:--

    “GAY LUSSAC was quick, lively, ingenious, and profound, with
    great activity of mind and great facility of manipulation. I
    should place him at the head of living chemists of France.”

    “BERTHOLLET was a most amiable man; when the friend of Napoleon
    even, always good, conciliatory and modest, frank and candid.
    He had no airs, and many graces. In every way below La Place
    in intellectual powers, he appeared superior to him in moral
    qualities. Berthollet had no appearance of a man of genius;
    but one could not look on La Place’s physiognomy without being
    convinced that he was a very extraordinary man.”

All accounts appear to show that Davy hardly treated his hosts with
the cordiality and respect they extended to him. His Chauvinism seemed
to get the better of his courtesy. There was, it is said, a flippancy
in his manner and a superciliousness and hauteur in his deportment
which surprised as much as they offended. Napoleon, with characteristic
bluntness, told one of the members of the Institute that he had
heard the young English chemist had a poor opinion of them all. Dr.
Paris, who could certainly speak from personal knowledge, states that
Davy’s unfortunate manner was not so much the expression of a haughty
consciousness of superiority as the desire to conceal a _mauvaise
honte_ and _gaucherie_--an ungraceful timidity he could never conquer,
and which often led him to force himself into a state of effrontery
and with a violence of effort which passed for a sally of pride or the
ebullition of temper.

Whatever Davy’s manner might have been, it was not allowed to affect
the admiration felt for his genius, and on December 13th, 1813, he was
with practical unanimity elected a Corresponding Member of the First
Class of the Institute.

During the last week of the preceding November Ampère had given Davy a
small quantity of a substance which he had obtained from Clement, and
which had been discovered by Courtois, a soap-boiler and manufacturer
of saltpetre in Paris, in kelp or the ashes of sea-weeds. The substance
had the extraordinary property of giving a violet-coloured vapour,
but its true nature and relations were unknown, and it was commonly
designated as X. Although actually known for some time previously, the
first public notice of its existence was made by Clement at a meeting
of the Institute on November 29th, 1813, and at the meeting on December
6th Gay Lussac presented a short note on the substance, to which he
gave the name _iode_, and stated that it had analogies to chlorine. A
week later--that is, on the day of Davy’s election to the Institute--a
letter from him to Cuvier was read, in which he gave a general view
of the chemical characters of the body; and on January 20th, 1814, a
paper by him, dated Paris, December 10th, 1813, and entitled “Some
Experiments and Observations on a new Substance which becomes a
violet-coloured Gas by Heat,” was read to the Royal Society.

After reciting the above facts he explains why he has ventured to take
up a subject on which Gay Lussac was still engaged. The explanation
was no doubt necessary; he had evidently not forgotten Gay Lussac’s
intrusion into his own field of work on the occasion of the discovery
of the metals of the alkalis. He first draws attention to the
peculiarities of the combination of the new substance with silver;
this, he shows, is markedly different from silver chloride. He then
forms this compound synthetically; forms also the combination with
potassium by direct union, and describes its properties; studies the
action of chlorine on the new substance, and notes the formation of
the yellow solid chloride and the mode of its decomposition by water;
prepares a number of metallic compounds; studies the action of the
new substance on phosphorus, the nature of the product, and its mode
of decomposition by water, with formation of the white crystalline
phosphonium iodide and hydriodic acid gas. By acting on this gas with
potassium he shows that it yields half its volume of hydrogen and forms
the same product as by the direct union of the alkali metal with the
new substance. He further finds that this gas is formed when the new
substance and hydrogen are passed through a heated tube; it has a very
strong attraction for water, which dissolves it to a large extent, and
the concentrated solution rapidly becomes tawny. When the new substance
is treated with potash solution it forms the same product as by its
direct union with potassium, together with a salt precisely similar to
potassium hyper-oxymuriate, and which, like that salt, is decomposed
when heated, with evolution of oxygen. He shows that the new substance
is expelled from its compounds when these are heated with chlorine.
He studies the nature of the black fulminating compound discovered
by Desormes and Clement by acting on the new substance with solution
of ammonia, and concludes that it is analogous to the detonating oil
of Dulong. He attempts to determine the combining proportion of the
new substance, on the assumption that its compounds are analogous to
those of chlorine, but he has to admit that his experiments have been
made upon quantities too small to afford exact results. Nevertheless
they prove that the value is much higher than those of the simple
inflammable bodies, and higher even than those of most of the metals.
He further shows that the combination with hydrogen must be one of the
heaviest elastic fluids existing.

    “From all the facts that have been stated, there is every reason
    to consider this new substance as _an undecompounded body_. In
    its specific gravity, lustre, colour, and the high number in
    which it enters into combination, it resembles the metals; but
    in all its chemical agencies it is more analogous to oxygen and
    chlorine; it is a non-conductor of electricity, and possesses,
    like these bodies, the negative electrical energy with respect
    to metals, inflammable and alkaline substances, and hence when
    combined with these substances in aqueous solution and electrized
    in the voltaic circuit, it separates at the positive surface; but
    it has a positive energy with respect to chlorine.... It agrees
    with chlorine and fluorine in forming acids with hydrogen.

    “The name _ione_ has been proposed in France for this new
    substance from its colour in the gaseous state, from ῐον, viola;
    and its combination with hydrogen has been named _hydroionic
    acid_. The name _ione_, in English, would lead to confusion, for
    its compounds would be called _ionic_ and _ionian_. By terming it
    _iodine_, from ἱώδης violaceous, this confusion will be avoided,
    and the name will be more analogous to chlorine and fluorine.”

The rapidity with which Davy ascertained the properties and relations
of the new substance was characteristic of him. A fortnight’s
work--done partly at his hotel and partly in the laboratory of the
young Chevreul, amidst a succession of interruptions caused by fêtes,
levées, and visits of ceremony--sufficed to accumulate the material for
his Royal Society paper, in which he gives with unerring precision, in
spite of the small quantity of the matter at his disposal, the broad
outlines of the chemistry of iodine. The paper shows him at his best:
he seems to have seized, as if by instinct, upon the central fact of
the analogy of iodine to chlorine, and he worked out the clue with a
perspicacity and insight worthy of his genius.

As may be surmised, Davy’s action hardly contributed to his popularity
with a certain section of the _savants_ of Paris. Gay Lussac and
Thenard were extremely angry with Ampère and Clement for having given
him the material for his investigation, and the feeling broke out after
the publication of Gay Lussac’s memoir in the Annales de Chimie in
1814. Davy in a note published in the Journal of the Royal Institution
says:--

    “Who had most share in developing the chemical history of that
    body [iodine], must be determined by a review of the papers
    that have been published upon it, and by an examination of
    their respective dates. When M. Clement showed Iodine to me, he
    believed that the hydriodic acid was muriatic acid; and M. Gay
    Lussac, after his early experiments, made originally with M.
    Clement, formed the same opinion, and _maintained_ it, when I
    _first_ stated to him my belief that it was a new and peculiar
    acid, and that Iodine was a substance analogous in its chemical
    relations to Chlorine.”

Davy left Paris towards the end of December, passing into Auvergne and
thence to Montpellier, where he resumed his work on iodine. He then
went to Genoa, where he made some experiments on the electricity of the
torpedo, and about the middle of March arrived at Florence. In a letter
to his brother John he says:--

    “I have worked a good deal on iodine and a little on the torpedo.
    Iodine had been in embryo for two years. I came to Paris;
    Clement requested me to examine it, and he believed that it was
    a compound, affording muriatic acid. I worked upon it for some
    time, and determined that it was a new body, and that it afforded
    a peculiar acid by combining with hydrogen, and this I mentioned
    to Gay Lussac, Ampère, and other chemists. The first immediately
    ‘took the word of the Lord out of the mouth of His servant,’
    and treated this subject as he had treated potassium and boron.
    The paper which I sent to the Royal Society on iodine I wrote
    with Clement’s approbation and a note published in the ‘Journal
    de Physique’ will vindicate my priority. I have just got ready
    for the Royal Society a second paper on this fourth supporter of
    combustion.

    “The old theory is nearly abandoned in France. Berthollet, with
    much candour, has decided in favour of chlorine. I know no
    chemist but Thenard who upholds it at Paris, and he upholds it
    feebly, and by this time, probably, has renounced it.

    “I doubt if the organ of the torpedo is analogous to the pile
    of Volta. I have not been able to gain any chemical effects by
    the shock sent through water; but I tried on small and not very
    active animals. I shall resume the inquiry at Naples, where I
    hope to be about the middle of May. In my journey I met with no
    difficulties of any kind, and received every attention from the
    scientific men of Paris, and the most liberal permission to go
    where I pleased from the government.

    “I lived very much with Berthollet, Cuvier, Chaptal, Vauquelin,
    Humboldt, Morveau, Clement, Chevreul, and Gay Lussac. They were
    all kind and attentive to me; and, except for Gay Lussac’s last
    turn of publishing without acknowledgement what he had first
    learnt from me, I should have had nothing to complain of; but who
    can control self-love?

    “It ought not to interfere with truth and justice; but I will not
    moralise nor complain. Iodine is as useful an ally to me as I
    could have found at home.”

At Florence he worked in the laboratory of the Accademia del Cimento
on iodine and on the diamond. The results of his work on iodine he
embodied in a paper read to the Royal Society on June 16th, 1814, which
deals mainly with the iodates, or, as he preferred to call them, the
_oxyiodes_. The object of his work on the diamond was to determine
whether any peculiar matter separated from it during its combustion,
and whether the gas formed in the process was precisely the same in
its chemical nature as that produced by the combustion of plumbago and
charcoal. At Florence he made use of the great burning-glass originally
employed in the trials on the action of solar heat on the diamond
instituted by Cosmo III., Grand Duke of Tuscany; he completed the
research in the laboratory of the Accademia dei Lincei at Rome.

From the results of his different experiments, which were communicated
to the Royal Society on June 23rd, 1814, it appeared that the diamond
affords no other substance by its combustion in oxygen than pure
carbonic acid gas, and that the only chemical difference perceptible
between diamond and the purest charcoal is that the latter contains
a minute proportion of hydrogen. “But,” he asks, “can a quantity of
an element, less in some cases than 1/50000 part of the weight of the
substance, occasion so great a difference in physical and chemical
characters?” This he concludes is most unlikely, for, as he points out,
even when the minute quantity of hydrogen is expelled by heating the
charcoal in chlorine, the specific differences remain.

The doctrine at that time current, and which seemed indeed almost
axiomatic, “That bodies cannot be exactly the same in composition
or chemical nature, and yet totally different in all their physical
properties,” received its first great shock. Davy’s work, no doubt,
paved the way for the recognition of the fact of allotropy, and
thereafter of isomerism.

In May he went to Naples and made his first ascent of Vesuvius,
which he revisited on several subsequent journeys. He commissioned
one of the guides to inform him from time to time of the condition
of the volcano, and the man’s letters, in spite of their phonetic
address--“Siromfredevi-Londra”--duly found their way to Albemarle
Street. He also interested himself in the excavations at Pompeii
instituted by direction of Murat, then King of Naples, and he performed
a number of experiments on the colours used by the ancients in
painting, an account of which was communicated to the Royal Society on
February 23rd, 1815.

He then passed northwards with the intention of spending the summer at
Geneva. On his way he called at Milan to pay his respects to Volta. Of
this visit he wrote:--

    “Volta I saw at Milan, in 1814, at that time advanced in
    years,--I think nearly seventy and in bad health. His
    conversation was not brilliant; his views rather limited, but
    marking great ingenuity. His manners were perfectly simple. He
    had not the air of a courtier, or even of a man who had seen the
    world.”

If Dr. Paris’s story is to be credited, the lack of brilliancy in
the conversation of the great Italian physicist may be attributed to
the circumstances of this meeting. Davy, we are told, had written to
announce his intended visit, and on the appointed day and hour Volta,
in full dress, awaited his arrival.

    “On the entrance of the great English philosopher into the
    apartment, not only in _déshabille_, but in a dress of which an
    English artisan would have been ashamed, Volta started back in
    astonishment, and such was the effect of his surprise, that he
    was for some time unable to address him.”

The party remained at Geneva until the middle of September, partaking
freely of the intellectual life which that charming city afforded. Here
he met Saussure Pictet, De la Rive, Madame de Staël, Benjamin Constant,
Necker, and Talma, whose society he greatly enjoyed. With the approach
of winter he returned to Italy _viâ_ the Brenner and Venice, and on
November 2nd arrived at Rome, where he remained until March 1st, 1815,
occupying himself with his inquiry into the composition of ancient
colours. In this he was greatly assisted by the kindness of his friend
Canova, the celebrated sculptor, who was then charged with the care
of the works connected with ancient art in Rome, and who supplied
him with material from the colours found in the Baths of Titus and of
Livia, and other palaces and baths of ancient Rome and Pompeii. Davy’s
memoir, which appears in the _Philosophical Transactions_ for 1815,
displays considerable antiquarian and bibliographical research, and,
considering his limited means, much analytical skill and ingenuity. The
ancient reds he found to consist of minium, several varieties of iron
ochre, and vermilion or cinnabar. The yellows were mixtures of ochres
and chalks, or of ochre with minium. He was unable to discover that
orpiment was used; a deep orange yellow on stucco in the ruins near
the monument of Caius Cestius consisted of a mixture of massicot and
minium. The blues were mainly mixtures of the Egyptian or Alexandrine
blue, with more or less chalk. This Egyptian blue, he found, was a
_frit_, made by heating soda, sand, and copper, either used as an ore
or as metal. He gives a method of making it, and speaks highly of its
permanence and beauty. The greens were, as a rule, compounds of copper.
The exact nature of the purples he was unable to determine; they were
probably organic, but whether obtained from shell-fish or madder could
not be ascertained. The purplish reds in the Baths of Titus were found
to be mixtures of red ochres, and the blues were copper compounds. The
blacks and browns were mixtures of carbonaceous matter with oxides of
iron or manganese. The whites were mainly chalk, or occasionally clay;
cerusse, or white-lead, was apparently not used.

Before leaving Italy he again went to Naples, for the purpose of
witnessing Vesuvius in eruption, and on several occasions he was as
near the crater as he could get. He left Naples on March 21st, and came
home by way of Verona, Innsbruck, Ulm, Stuttgart, Heidelberg, and
the Rhine, arriving in London April 23rd, 1815. A few days after his
arrival he wrote to his mother:--

    “We have had a very agreeable and instructive journey and Lady
    Davy agrees with me in thinking that England is the only country
    to _live_ in, however interesting it may be to _see_ other
    countries.

    “I yesterday bought a good house in Grosvenor Street, and we
    shall sit down in this happy land.

    “I beg you to give my best and kindest love to my sisters, and to
    remember me with all affection to my aunts.”

Faraday was again engaged as assistant in the laboratory of the Royal
Institution and superintendent of the apparatus (at a salary of 30s. a
week), and was accommodated with apartments at the top of the house.

In Dr. Bence Jones’s “Life of Faraday” we have more detailed
information concerning this tour, derived from the journal which
Faraday kept whilst he was abroad. Faraday describes in considerable
detail the life in Paris and the work on Iodine; we have accounts of
Chevreul’s laboratory at the Jardin des Plantes, and of Gay Lussac’s
lectures at the École Polytechnique; of the work on the torpedo at
Genoa; of the combustion of the diamond at the Accademia del Cimento,
and a description of the great burning-glass, and how it was actually
employed; of the experiments of Morichini on the alleged magnetisation
of a needle by the solar rays; of his meeting Volta--“an hale, elderly
man, bearing the red ribbon, and very free in conversation”; of the
work at Rome on chlorous oxide and iodic acid, and on the pigments
employed by the ancients.

    “The constant presence of Sir Humphry Davy,” wrote Faraday to
    his friend Abbott, “is a mine inexhaustible of knowledge and
    improvement.” But he adds: “I have several times been more than
    half decided to return hastily home; but second thoughts have
    still induced me to try what the future may produce ... the
    glorious opportunities I enjoy of improving in the knowledge
    of chemistry and the sciences continually determine me to
    finish this voyage with Sir H. D. But if I wish to enjoy these
    advantages I have to sacrifice much, and though these sacrifices
    are such as an humble man would not feel, yet I cannot quietly
    make them.”

Faraday’s troubles arose from his anomalous position in the party. When
Davy elected to go abroad, he arranged to take his valet with him; but
at the eleventh hour this man, moved by the tears of his wife--to whom
the “Corsican Ogre” was a kind of bogey--refused to proceed. “When Sir
H. informed me of this circumstance,” says Faraday, “he expressed his
sorrow at it, and said--that if I would put up with a few things on
the road until he got to Paris, doing those things which could not be
trusted to strangers or waiters ... he would get a servant.... At Paris
he could find no servant to suit him,” nor was he more successful at
Montpellier or at Genoa. It was, doubtless, difficult at this period
to find a man in such places who understood English and was in other
respects suitable. Faraday goes on to say:--

    “Sir Humphry has at all times endeavoured to keep me from the
    performance of those things which did not form a part of my duty,
    and which might be disagreeable.... I should have but little to
    complain of, were I travelling with Sir Humphry alone, or were
    Lady Davy like him; but her temper makes it oftentimes go wrong
    with me, with herself and with Sir H....

    “She likes to show her authority, and at first I found her
    extremely earnest in mortifying me. This occasioned quarrels
    between us, at each of which I gained ground and she lost it; for
    the frequency made me care nothing about them, and weakened her
    authority, and after each she behaved in a milder manner.”

How Davy and his wife appeared to the world at this time may be seen
from the following extracts from Ticknor’s Life:--

    “1815. June 13.--I breakfasted this morning with Sir H.
    Davy, of whom we have heard so much in America. He is now
    about thirty-three [he was actually thirty-seven], but with
    all the freshness and bloom of twenty-five, and one of the
    handsomest men I have seen in England. He has a great deal of
    vivacity--talks rapidly, though with great precision--and is so
    much interested in conversation that his excitement amounts to
    nervous impatience, and keeps him in constant motion. He has just
    returned from Italy, and delights to talk of it; thinks it, next
    to England, the finest country in the world, and the society of
    Rome surpassed only by that of London, and says he should not die
    contented without going there again.”

    “15 June.--As her husband had invited me to do, I called this
    morning on Lady Davy. I found her in her parlour, working on a
    dress, the contents of her basket strewed about the table, and
    looking more like home than anything since I left it. She is
    small, with black eyes and hair and a very pleasant face, an
    uncommonly sweet smile; and when she speaks has much spirit and
    expression in her countenance. Her conversation is agreeable,
    particularly in the choice and variety of her phraseology, and
    has more the air of eloquence than I have ever heard before
    from a lady. But, then, it has something of the appearance of
    formality and display, which injures conversation. Her manner is
    gracious and elegant; and though I should not think of comparing
    her to Corinne yet I think she has uncommon powers.”

In Henry Crabb Robinson’s Diary we read, under date May 31st, 1813:--

    “Dined with Wordsworth at Mr. Carr’s. Sir Humphry and Lady
    Davy there. She and Sir H. seem to have hardly finished their
    honeymoon. Miss Joanna Baillie said to Wordsworth, ‘We have
    witnessed a picturesque happiness.’”

In 1815 it was very evident the honeymoon had waned and that the
picturesque happiness was at an end. However fitted her ladyship
might be to shine in salons, at routs and fashionable gatherings, she
lacked the homelier, kindlier charms which grace the _placens uxor_.
An accomplished woman, of fastidious taste, fond of study, upright
in her dealings, and charitable to the poor, she was withal cold
and unsympathetic, self-willed and independent, “fitted to excite
admiration rather than love, and neither by nature happy in herself,
or qualified to impart, in the best sense of the term, happiness to
others.” Such is the character given of her by Dr. Davy; and he adds,
“There was an oversight, if not a delusion, as to the fitness of their
union”; and “it might have been better for both if they had never met.”
It was, no doubt, from the fulness of his own experience that Davy once
wrote to a friend:--

    “Upon points of affection it is only for the parties themselves
    to form just opinions of what is really necessary to ensure
    the felicity of the marriage state. Riches appear to me not at
    all necessary, but competence, I think is; and after this more
    depends upon the _temper_ of the individual than upon personal,
    or even intellectual circumstances. The finest spirits, the most
    exquisite wines, the nectars and ambrosias of modern tables, will
    be all spoilt by a few drops of bitter extract; and a bad temper
    has the same effect in life, which is made up, not of great
    sacrifices or duties, but of little things, in which smiles and
    kindness, and small obligations given habitually, are what win
    and preserve the heart, and secure comfort.”




CHAPTER X.

THE SAFETY LAMP.


Shortly after Davy’s return to England his sympathy was enlisted in a
cause which enabled him to display all the attributes of his genius,
and to achieve a triumph which, while greatly enhancing his popular
reputation, added no little to his scientific fame. To show him how
he might be useful, was at all times a certain method of securing his
interest; for, like Lavoisier, he was even more the friend of humanity
than of science, and to make science serviceable to humanity was, he
considered, the highest object of his calling.

During the early years of this century the country was repeatedly
shocked by the occurrence of a succession of disastrous colliery
explosions, especially in the north of England, attended by
great destruction of life and property and widespread misery and
destitution. The development of our iron-trade, the improvements in
the steam-engine, and the more general application of machinery to
industry had greatly stimulated the opening out of our coal-fields; and
the working of coal was being extended with a rapidity that greatly
aggravated the evils and dangers at all times inseparable from it.
In the early days of coal-getting, when the pits were shallow and
the workings comparatively near the shafts, fire-damp, although not
unheard of, was little dreaded, and explosions were rare--so rare,
indeed, that when they occurred they were thought worthy of mention
in the _Philosophical Transactions_ of the Royal Society. As the pits
became deeper, and the ways more extended, explosions became more
frequent, and at times it was impossible to work the coal, owing to the
accumulation of fire-damp and its liability to “fire” at the candles of
the miners. In 1732 attempts were first made to ventilate the pits by
“fire-lamps” or furnaces, and by mechanical means, so as to sweep out
the “sulphur” by means of fresh air. Carlisle Spedding, a little later,
invented the steel mill--a contrivance by which a disc of steel was
caused to revolve against a piece of flint, so as to throw off a shower
of sparks sufficiently luminous to enable the miner to carry on his
business.

In spite of the “spark-emitting wheel,” and of the systems of
ventilation introduced by Ryan, James Spedding, John Buddle, and
others, “the swart demon of the mine” grew more and more formidable,
and demanded a greater number of victims every year. Mechanical
science would appear to have spent itself, and the mining world was
gradually coming to look upon fire-damp with the fatalism with which
ignorant and superstitious people regard the plague. Some of the
great coal owners--powerless to do more, but afraid of the rising
tide of public opinion--used their influence with the newspapers
to suppress all allusion to these calamities. But many persons,
especially the physicians and clergymen in the mining districts, who
were witnesses of the suffering and distress which the “firing” of a
mine occasioned, kept public attention alive by means of pamphlets
and letters and notices to such journals as would insert their
communications. One colliery--the Brandling Main or Felling Colliery,
near Gateshead-on-Tyne--acquired an unenviable notoriety from the
frequency with which it fired. On May 25th, 1812, an explosion occurred
which killed ninety-two men and boys. No calamity of such magnitude
had ever happened before in a coal mine. Eighteen months afterwards
a second explosion took place by which twenty-three lives were lost.
In the following year explosions occurred at Percy Main, Hebburn, and
Seafield. In June, 1815, Newbottle Colliery exploded with the loss
of fifty-seven men and boys, and this was immediately followed by a
similar disaster at Sheriff Hill. The Rev. Mr. Hodgson--the historian
of Northumberland--in whose parish the Brandling Main was situated,
published a particular account of the first Felling Colliery Explosion.
This was widely circulated, and ultimately found its way into Thomson’s
_Annals of Philosophy_, which continued to print accounts of similar
accidents as they occurred. At length Mr. J. J. Wilkinson, a barrister
resident in the Temple, suggested the formation of a society to
investigate the whole subject and to seek for remedies. The Bishop of
Durham and the Rev. Dr. Gray, afterwards Bishop of Bristol, but then
Rector of Bishopwearmouth, led the way, and ultimately the society was
instituted on October 1st, 1813, with Sir Ralph Millbanke, afterwards
Sir Ralph Noel, as President. Its first report contains a letter
from Mr. John Buddle, the great authority on the ventilation of coal
mines, in which he expresses his conviction that mechanical agencies
are practically powerless to prevent explosions in mines subjected to
sudden bursts of fire-damp, and he concludes

    “that the hopes of this society ever seeing its most desirable
    object accomplished must rest upon the event of some method
    being discovered of producing such a chemical change upon
    carburetted hydrogen gas as to render it innoxious as fast as it
    is discharged, or as it approaches the neighbourhood of lights.
    In this view of the subject, it is to scientific men only that we
    must look up for assistance in providing a cheap and effectual
    remedy.”

The society received a number of suggestions, for the most part wholly
impracticable, and generally of the character of that of Dr. Trotter,
who proposed to flood the mines with chlorine. A variety of air-tight
or insulated lamps were suggested by Clanny, Brandling, Murray, and
others, much on the same lines as that devised by Humboldt, but none of
them appears to have been seriously tried.

Under these circumstances it was decided to ask for the co-operation of
Davy, and with that object Mr. Wilkinson called upon him at the Royal
Institution, in the autumn of 1813, but found he had left for Paris.
A few months after his return the Rev. Dr. Gray wrote to him on the
subject, and received the following letter in reply:--

            “_August 3, 1815._

    “....

    “It will give me great satisfaction if my chemical knowledge can
    be of any use in an enquiry so interesting to humanity, and I beg
    you will assure the committee of my readiness to co-operate with
    them in any experiments or investigations on the subject.

    “If you think my visiting the mines can be of any use, I will
    cheerfully do so.

       *       *       *       *       *

    “I shall be here ten days longer, and on my return South, will
    visit any place you will be kind enough to point out to me, where
    I may be able to acquire information on the subject of coal gas.”

Dr. Gray, in reply, referred him to Mr. John Buddle, of the Wallsend
Colliery.

On August 24th, 1815, Mr. Buddle wrote to Dr. Gray:--

    “Permit me to offer my best acknowledgments for the opportunity
    which your attention to the cause of humanity has afforded me of
    being introduced to Sir Humphry Davy.

    “I was this morning favoured with a call from him, and he was
    accompanied by the Rev. Mr. Hodgson. He made particular enquiries
    into the nature of the danger arising from the discharge of the
    inflammable gas in our mines. I shall supply him with a quantity
    of the gas to analyze; and he has given me reason to expect that
    a substitute may be found for the steel mill, which will not fire
    the gas. He seems also to think it possible to generate a gas,
    at a moderate expense, which, by mixing with the atmospheric
    current, will so far neutralise the inflammable air, as to
    prevent it firing at the candles of the workmen.

    “If he should be so fortunate as to succeed in either the one
    or the other of these points, he will render the most essential
    benefit to the mining interest of this country, and to the cause
    of humanity in particular.”

After spending a few days in the district with Mr. Hodgson and Dr.
Gray, in the course of which he saw and experimented with Dr. Clanny’s
lamp, he went on a round of visits in Durham and Yorkshire, and arrived
in London at the end of September. Early in October a quantity of
fire-damp was sent to him by Mr. Hodgson, the receipt of which he
acknowledged on the 15th, saying:--

    “My experiments are going on successfully and I hope in a few
    days to send you an account of them; I am going to be fortunate
    far beyond my expectations.”

Four days afterwards he again wrote to Mr. Hodgson stating that he had
discovered

    “that explosive mixtures of mine-damp will not pass through
    small apertures or tubes; and that if a lamp or lanthorn be made
    air-tight on the sides, and furnished with apertures to admit the
    air, it will not communicate flame to the outward atmosphere.”

On the 25th October he gave an account of his work to the Chemical
Club. On October 30th he wrote to Dr. Gray and to Mr. Hodgson, giving a
description of three forms of _safe lamps_. His letter to Dr. Gray was
as follows:--

    “As it was the consequence of your invitation that I endeavoured
    to investigate the nature of the fire-damp, I owe to you the
    first notice of the progress of my experiments.

    “My results have been successful far beyond my expectations. I
    shall enclose a little sketch of my views on the subject; and I
    hope in a few days to be able to send a paper with the apparatus
    for the committee. I trust the _safe lamp_ will answer all the
    objects of the collier.

    “I consider this at present as a private communication. I wish
    you to examine the lamps I have had constructed, before you give
    any account of my labours to the committee.

    “I have never received so much pleasure from the result of any of
    my chemical labours; for I trust the cause of humanity will gain
    something by it.”

Mr. Hodgson’s letter was shown to several persons, and appears to have
been copied by some, on or about November 2nd, and an extract from it
appeared in Dunn’s “View of the Coal Trade.”

On November 9th Davy read his first paper on the subject before the
Royal Society; it was entitled “On the fire-damp of coal mines, and
on the methods of lighting the mines so as to prevent its explosion.”
After describing the manner in which his attention had been specially
called to the subject, he states that he first made experiments with
a variety of phosphori (Kunckel’s, Canton’s, and Baldwin’s), and also
with the electrical light in close vessels, in the hope that they
might be found to afford the requisite amount of illumination; but the
results were not encouraging.

After an account of the chemical characters of the fire-damp sent to
him by Mr. Hodgson, he describes the results of experiments on its
combustibility and explosive nature, and on the degree of heat required
to explode it when mixed with air. In respect of its combustibility
fire-damp was found to differ most materially from the other common
inflammable gases in that it required a far higher temperature to
effect its inflammation or explosion. Moreover, it was found that the
flame formed by the union of air and fire-damp would not pass through
tubes of a certain minimum diameter;

    “and in comparing the power of tubes of metal and those of glass,
    it appeared that the flame passed more readily through glass
    tubes of the same diameter; and that explosions were stopped
    by metallic tubes of one-fifth of an inch when they were an
    inch and a half long; and this phenomenon probably depends upon
    the heat lost during the explosion in contact with so great
    a cooling surface, which brings the temperature of the first
    portions exploded below that required for the firing of the other
    portions. Metal is a better conductor of heat than glass; and it
    has been already shown that fire-damp requires a very strong heat
    for its inflammation.”

The observation that mixtures of air and coal-gas would not explode
in very narrow tubes had been previously made, unknown to Davy, by
Wollaston and Tennant. Davy likewise found that explosions would not
pass through very fine wire sieves or wire gauze. He also noted that
an admixture of carbonic acid and nitrogen, even in small proportions,
with explosive mixtures of fire-damp greatly diminished the velocity of
the inflammation.

    “... It is evident then, that to prevent explosions in coal mines
    it is only necessary to use air-tight lanterns, supplied with
    air from tubes or canals of small diameter, or from apertures
    covered with wire-gauze placed below the flame, through which
    explosions cannot be communicated and having a chimney at the
    upper part, as a similar system for carrying off the foul air;
    and common lanterns may be easily adapted to the purpose by being
    made air-tight in the door and sides, by being furnished with the
    chimney and the system of safety apertures below and above. The
    principle being known, it is easy to adapt and multiply practical
    applications of it.”

[Illustration: DAVY’S EXPERIMENTAL SAFETY LAMPS.]

He then devised a number of lamps on this principle, and subjected
them to trial with explosive mixtures in various ways. The plate
on page 199, copied from the original paper in the _Philosophical
Transactions_, shows the successive forms through which the lamps
passed.

[Illustration]

On January 11th, 1816, he read a second paper to the Royal Society,
entitled, “An account of an invention for giving light in explosive
mixtures of fire-damp in coal mines by consuming the fire-damp,” in
which he shows that the tubes or canals as well as the sides of the
lanterns may be replaced by cages or cylinders of wire gauze. The
inflammable mixture will readily pass through the meshes of the gauze
and will burn within it, filling the cylinder with a bright flame, but
no explosion will pass outwards, even although the wire becomes heated
to redness.

A fortnight later he read a third paper to the Society, “On the
Combustion of Explosive Mixtures confined by Wire Gauze, with some
Observations on Flame,” in which he gives the results of further
inquiries respecting the limits of the size of the apertures, and of
the wire in the metallic gauze required to shield the flame of an
oil-lamp, and describes a number of illustrations of the action of
the gauze in lowering the temperature of the explosive mixture below
the point of ignition. Some of these illustrations are now among the
stock experiments of the lecture theatre. He offers some observations
concerning the essential nature of flame, and concludes by informing
the Society that his “cylinder lamps [_i.e._ lamps of which the flames
are enclosed within a cylinder of gauze: see Fig. 11, p. 199] have been
tried in two of the most dangerous mines near Newcastle with perfect
success.”

The form which the lamp finally took in the hands of Mr. Newman, the
instrument-maker, is seen on p. 200.

The trials above referred to were first made by Mr. Matthias Dunn and
the indefatigable Mr. Hodgson in the Hebburn Colliery, and shortly
afterwards by Mr. John Buddle in the Wall’s End Colliery. Mr. Buddle
has placed on record his impressions of his first experience.

    “I first tried it,” he says, “in an explosive mixture on the
    surface; and then took it into a mine; ... it is impossible for
    me to express my feelings at the time when I first suspended the
    lamp in the mine and saw it red hot.... I said to those around me
    ‘We have at last subdued this monster.’”

Some months afterwards Davy accompanied Mr. Buddle into the pit and saw
his lamp in actual use.

    “Sir Humphry was delighted,” says Mr. Buddle, “and I was
    overwhelmed with feelings of gratitude to that great genius which
    had produced it.”

Further testimony of Mr. Buddle’s appreciation of this memorable
invention may be seen from the following extract from a letter by him
to Davy. It is not only interesting in view of Davy’s remark that “the
evidence of the use of a practical discovery is of most value when
furnished by practical men,” but also as showing the rapidity with
which the discovery was taken advantage of:--

            “Walls End Colliery, Newcastle, _June 1st, 1816_.

    “After having introduced your safety lamp into general use
    in all the collieries under my direction, where inflammable
    air prevails, and after using them daily in every variety of
    explosive mixture, for upwards of three months, I feel the
    highest possible gratification in stating to you that they have
    answered to my entire satisfaction.

    “The safety of the lamps is so easily proved by taking them
    into any part of a mine charged with fire-damp, and all the
    explosive gradations of that dangerous element are so easily and
    satisfactorily ascertained by their application, as to strike the
    minds of the most prejudiced with the strongest conviction of
    their high utility; and our colliers have adopted them with the
    greatest eagerness.

    “Besides the facilities afforded by this invention to the
    working of coal mines abounding in fire-damp, it has enabled
    the directors and superintendents to ascertain, with the utmost
    precision and expedition, both the presence, the quantity, and
    the correct situation of the gas. Instead of creeping inch
    by inch with a candle, as is usual, along the galleries of a
    mine suspected to contain fire-damp, in order to ascertain
    its presence, we walk firmly in with the safe lamps, and with
    the utmost confidence prove the actual state of the mine. By
    observing attentively the several appearances upon the flame of
    the lamp, in an examination of this kind, the cause of accidents
    which have happened to the most experienced and cautious miners
    is completely developed; and this has been, in a great measure,
    matter of mere conjecture.

    “I feel peculiar satisfaction in dwelling upon a subject which
    is of the utmost importance, not only to the great cause of
    humanity, and to the mining interest of the country, but also
    to the commercial and manufacturing interests of the United
    Kingdom; for I am convinced that by the happy invention of the
    safe lamp large proportions of the coal mines of the empire
    will be rendered available, which otherwise might have remained
    inaccessible, at least without an invention of similar utility,
    which could not have been wrought without much loss of the
    mineral, and risk of life and capital.

    “It is not necessary that I should enlarge upon the national
    advantages which must necessarily result from an invention
    calculated to prolong our supply of mineral coal, because I think
    them obvious to every reflecting mind; but I cannot conclude,
    without expressing my highest sentiments of admiration for those
    talents which have developed the properties, and controlled
    the power, of one of the most dangerous elements which human
    enterprise has hitherto had to encounter.”

This letter is only one of many received by Davy from practical men,
all telling the same story of wonder and astonishment “that so simple
a looking instrument should defy an enemy heretofore unconquerable”;
and all expressing the deepest gratitude to him as its inventor, often
in language which gains in force, and even in eloquence, from its very
homeliness and simple pathos.

The following address from the Whitehaven colliers was among the papers
lent to me by Dr. Rolleston:--

            “_September 18, 1816._

    “We, the undersigned, miners at the Whitehaven Collieries,
    belonging to the Earl of Lonsdale, return our sincere thanks to
    Sir Humphry Davy, for his invaluable discovery of the safe lamps,
    which are to us life preservers; and being the only return in
    our power to make, we most humbly offer this, our tribute of
    gratitude.”

        The names of eighty-two miners are appended--the majority of
        them--viz. forty-seven--with their mark (+) affixed.

What the learned world thought may be judged from the following
extracts from an article in the _Edinburgh Review_--a periodical not
always characterised by a just appreciation of the work of the Royal
Institution professors, for the literature of science contains few
things more disingenuous or more spiteful than the attack of “the young
gentleman from Edinburgh”--afterwards known as Lord Brougham--on Thomas
Young when he first made known the undulatory theory of light. In the
_Review_ for February, 1816, Mr. Playfair begins his article on Davy’s
discovery by pointing out that--

    “The safe lamp is a present from philosophy to the arts, and to
    the class of men furthest removed from the influence of science.
    The discovery is in no degree the effect of accident; and chance,
    which comes in for so large a share in the credit of human
    inventions, has no claims on one which is altogether the result
    of patient and enlightened research....

    “This is exactly such a case as we should choose to place before
    Bacon, were he to revisit the earth, in order to give him, in a
    small compass, an idea of the advancement which philosophy has
    made, since the time when he had pointed out to her the route
    which she ought to pursue. The great use of an immediate and
    constant appeal to experiment cannot be better evinced than in
    this example. The result is as wonderful as it is important. An
    invisible and impalpable barrier made effectual against a force
    the most violent and irresistible in its operations; and a power,
    that in its tremendous effects seemed to emulate the lightning
    and the earthquake, confined within a narrow space, and shut
    up in a net of the most slender texture,--are facts which must
    excite a degree of wonder and astonishment from which neither
    ignorance nor wisdom can defend the beholder. When to this we
    add the beneficial consequences and the saving of the lives of
    men and consider that the effects are to remain as long as coal
    continues to be dug from the bowels of the earth, it may fairly
    be said that there is hardly in the whole compass of art or
    science a single invention of which one would rather wish to be
    the author.”

Davy was urged by several of his friends to protect his invention by a
patent. Among them was Mr. Buddle, who pointed out to him that he might
have received his five or ten thousand a year from it.

    “My good friend,” was his answer, “I never thought of such a
    thing: my sole object was to serve the cause of humanity; and
    if I have succeeded, I am amply rewarded in the gratifying
    reflection of having done so.... More wealth could not increase
    either my fame or my happiness. It might undoubtedly enable me
    to put four horses to my carriage; but what would it avail me to
    have it said that Sir Humphry drives his carriage and four?”

The gratitude of some of the leading colliery proprietors for an
invention so unselfishly placed at their disposal found expression in
a letter from the chairman of a general meeting of the coal-owners
held at Newcastle on March 18th, 1816, conveying the terms of a vote
of thanks. A few months afterwards it was determined that their
appreciation should take a more substantial form, and a general meeting
of the coal-owners was held at Wallsend Colliery on August 31st, 1816,
at which it was resolved to make Davy a present of plate.

A note of opposition was at once sounded, and it came from one of the
proprietors of the Felling Colliery. Mr. W. Brandling urged that it was
not proved that Sir Humphry Davy was the first and true inventor of the
safety lamp, or even the discoverer of the principle on which it was
based.

    “The conviction,” he said, “upon my mind is, that Mr. George
    Stephenson, of Killingworth Colliery, is the person who first
    discovered and applied the principle upon which safe lamps may
    be constructed; for whether the hydrogen gas is admitted through
    capillary tubes, or through the apertures of wire-gauze, which
    may be considered as merely the orifices of capillary tubes, does
    not, as I conceive, in the least affect the principle.”

The opposition thus started very quickly gathered strength, and by
appeals to local prejudice and to ignorance a degree of heat and
even animosity was imported into the question, which served no other
purpose than to confuse the true issue. At an adjourned meeting of the
coal-owners held on October 11th, 1816, Mr. William Brandling moved--

    “That the meeting do adjourn, until by a comparison of dates it
    shall be ascertained whether the merit of the safety lamp belongs
    to Sir Humphry Davy, or to Mr. George Stephenson.”

Although Mr. Brandling failed to convince the meeting, it becomes
necessary in the interests of truth and justice to examine the grounds
upon which George Stephenson--a man of undoubted genius, and of an
integrity as blameless as that of Davy, and who, as the pioneer of
railway enterprise, subsequently acquired a fame as high and as
deserved as that of the great chemist--has claims to be regarded as an
inventor of the safety lamp. In equity, it must be admitted that the
question is not merely a question of dates, for in assigning merit in
a matter of this kind the calmer judgment of posterity is not wholly
swayed by priority of date; it looks to circumstances, conditions,
motives, and it apportions its meed of approbation accordingly. The
glory of Priestley as an independent discoverer of oxygen is in nowise
dimmed by the circumstance that Scheele is now known to have discovered
it before him. It cannot be truthfully asserted that Davy was not an
independent inventor of the safety lamp. What has to be determined is,
has George Stephenson any such claim?

Stephenson’s claim has been ably and temperately stated by Dr. Smiles
in his biography of George Stephenson, in “The Lives of the Engineers,”
but an unbiassed review of the evidence will convince most people that,
however certain it may be that the Killingworth engine-tenter was
an independent searcher after a method of protecting a flame, it is
equally certain that he was not the discoverer of the true principle on
which the safety lamp is constructed, and that the lamp associated with
his name, although it bears the impress of the crude ideas with which
he started, owes its real merit to the discoveries of Davy.

This controversy and the feeling it gave rise to greatly exasperated
Davy, and his anger is manifested in his letters at the time. The
action of the Brandlings he seemed to think was inspired by the most
unworthy motives. As to his rival, he says:--

    “I never heard a word of George Stephenson and his lamps till
    six weeks after my principle of security had been published; and
    the general impression of the scientific men in London, which is
    confirmed by what I heard at Newcastle, is, that Stephenson had
    some loose idea floating in his mind, which he had unsuccessfully
    attempted to put in practice till after my labours were made
    known;--then, he made something like a safe lamp, except that it
    is not _safe_, for the apertures below are four times, and those
    above twenty times too large; but, even if Stephenson’s plans had
    not been posterior to my principles, still there is no analogy
    between his glass exploding machine, and my metallic tissue
    permeable to light and air, and impermeable to flame.”

On the 25th of September, 1817, as Davy passed through Newcastle
on his return from Scotland, the coal-owners who had subscribed to
his testimonial invited him to a banquet and presented him with the
plate, which, in accordance with his wishes, took the form of a
dinner-service. “I wish,” he had said, “that even the plate from which
I eat should awaken my remembrance of their liberality, and put me in
mind of an event which marks one of the happiest periods of my life.”
The chairman--his friend Mr. Lambton, afterwards the Earl of Durham,
and who was with him under the care of Dr. Beddoes at Bristol--made
the presentation in an impressive and felicitous speech, and Davy
acknowledged it in terms worthy of himself and of the occasion. In a
subsequent speech, in response to the toast of his health, he dilated
upon the theme always uppermost in his mind, and to which he never
neglected the opportunity to give utterance, namely, the benefit of
abstract science to mankind. He had an admirable moral to which to
point, and it was driven home with all his wonted skill and power.

In what manner this plate, which was valued at about £2,500, was
subsequently made subservient to the interests of science will be seen
hereafter.

The friends of Stephenson were not wanting in the courage of their
convictions or in determination to give substantial proof of it. In the
following November they met and resolved that as in their opinion Mr.
G. Stephenson had been the first to discover the principle of safety
and to apply it, he was entitled to some reward. Whereupon Davy’s
friends again assembled in public meeting on November 26th, 1817,
and passed resolutions to the effect that in their opinion the merit
belonged to Sir Humphry Davy alone, and that Stephenson’s latest lamps
were evident imitations of those of Sir Humphry Davy; and they further
ordered that copies of their resolutions should appear in a number
of local, London, and Edinburgh papers, and be sent to the principal
owners and lessors of collieries upon the Tyne and Wear. Davy’s
friends in London also exerted themselves in his behalf, and a copy of
resolutions similar in purport to those passed in Newcastle, signed by
Sir Joseph Banks, P.R.S., Brande, Hatchett, and Wollaston, was sent to
the newspapers.

Mr. Brandling and his friends eventually collected about £800
(including 100 guineas which the meeting of October 11th had awarded
Stephenson as an acknowledgment of his efforts to construct a safe
lamp), and gave it, together with a silver tankard, to Mr. Stephenson
at a public dinner in January, 1818.

This is not the place to follow the subsequent history of the Davy
lamp, or to describe the various modifications which have grown out of
it, or even to show the dangers which a larger experience reveals as
latent in its original form. These dangers have in great measure arisen
from the development of the very system of ventilation which Buddle
himself instituted; and he who in his joy exultingly exclaimed, “At
last, we have subdued this monster!” has unwittingly contributed to the
maleficent activity of the monster in coping with the lamp as Buddle
knew it.

In the course of his numerous trials made to elucidate the principle
of the safety lamp, Davy observed certain peculiarities connected with
flame which led him to take up the general question. Hence arose a
series of investigations, which have contributed in no small degree to
our knowledge of a particularly difficult and intricate subject.

He proved, in the first place, that flame must be considered as an
_explosive mixture_ of inflammable gas or vapour and air, and that
the heat communicated by it must depend upon its mass. The different
appearance of a flame of coal gas burning in a jet in the open air, and
in his safety lamp mixed with common air, led him to investigate the
cause of luminosity in flame. He says:--

    “In reflecting on the circumstances of the two species of
    combustion I was led to imagine that the cause of the superiority
    of the light of the _stream_ of coal gas might be owing to the
    _decomposition_ of a part of the gas towards the interior of the
    flame, where the air was in smallest quantity, and the deposition
    of solid charcoal, which, first by its _ignition_, and afterwards
    by its combustion, increased in a high degree the intensity of
    the light.”

The principle of the increase of the brilliancy and density of flame
by the production and ignition of solid matter explains the appearance
of the different parts of the flames of burning bodies, and of the
blow-pipe flame; it also explains the intensity of the light of those
flames in which fixed solid matter is produced in combustion, _e.g._
phosphorus and zinc in oxygen, potassium in chlorine; and, on the
other hand, the feebleness of the light of flames in which gaseous
and volatile matter is alone produced, _e.g._ hydrogen in oxygen,
phosphorus in chlorine. Davy’s theory has not been unchallenged, but
all subsequent research, when pushed sufficiently far, has shown that,
as regards all ordinary illuminating flames, _i.e._ carbonaceous
flames--_e.g._ coal-gas, oil, paraffin, candle--the presence of solid
incandescent carbon is a prime cause of their luminosity. It had
been observed that the rarefaction of a mixture of inflammable gases
diminishes its combustibility: Davy proved that this diminution was
not the result of the removal of pressure _per se_, but of the cooling
effect thus indirectly produced. Hence, the lower the temperature of
ignition of a gaseous mixture the more it may be rarefied without
becoming uninflammable. In like manner he shows that by heating the
gaseous mixture it may be caused to explode at a lower temperature,
and that when gases combine by sudden compression, the combination is
caused by the heat evolved. Also that the power of an indifferent gas
to prevent the explosion of a gaseous mixture depends upon its power
of abstracting heat, and that the higher the temperature of ignition
of the explosive mixture the less is the amount of indifferent gas
required to stop the explosion. He proved that it was quite possible
to effect the gradual combination of gases without flame--that is,
without the production of heat sufficient to raise the products to
incandescence; and he discovered the singular fact that platinum would
induce the combination of many inflammable gases and vapours, and on
this circumstance based the construction of his flameless lamp.

       *       *       *       *       *

In the early summer of 1818, he thus wrote to his mother:--

    “MY DEAR MOTHER,--We are just going on a very interesting
    journey. I am first to visit the coal miners of Flanders, who
    have sent me a very kind letter of invitation and of thanks for
    saving their lives. We are then going to Austria, where I shall
    show Vienna to Lady Davy, and then visit the mines; and lastly,
    before I return, we are going to visit Naples.

    “I have the commands of his Royal Highness the Prince Regent to
    make experiments upon some very interesting ancient manuscripts,
    which I hope to unfold. I had yesterday the honour of an audience
    from his Royal Highness, and he commissioned me to pursue this
    object in the most gracious and kind manner....

    “We shall be absent some months. With kindest love to my sisters
    and my aunts,

            “I am, my dear mother,
                  “Your most affectionate son,
                                      “H. DAVY.”

A few months after this visit to the Prince Regent he received the
intimation that he had been created a baronet.

He arrived at Naples in the autumn, and began his researches on the
Herculaneum manuscripts referred to in his letter. His first results
were sufficiently encouraging to induce him to make some prolonged
experiments with a view of discovering a method of unfolding them.
He found that the papyri had suffered not so much from fire, as was
believed, as from a gradual change in vegetable structure, similar
to that which accompanies the transformation of vegetable matter
into lignite. He managed to unroll a number, and an account of his
results was communicated to the Royal Society in 1821. But from the
fragmentary character of the papyri these were found to be of little
value to literature. Subsequently difficulties were put in his way by
the curators of the museum, and ultimately his investigations were
abandoned, not without some little exhibition of temper and resentment
on his part.

During his stay at Naples he again interested himself in the volcanic
phenomena of Vesuvius, and his observations constitute the material
of a paper which was published in the _Philosophical Transactions_
in 1827, and many of his personal experiences in connection with the
subject are referred to in his last work, “Consolations in Travel.”

He left Naples in the spring of 1819, and after a short stay at the
baths of Lucca he went for the summer and early autumn into the Tyrol,
whence he again proceeded to Lucca, and on the approach of winter
returned to Naples, where he arrived on December 1st. He quitted it
in the spring of 1820, and travelled slowly home by the south of
France and Bordeaux, arriving in England about the middle of June. On
the 19th of that month Sir Joseph Banks died, and so terminated his
forty-two years’ presidency of the Royal Society, to which position he
was elected before Davy was even born. Davy immediately announced his
intention of becoming a candidate for the vacant chair, and was elected
at the following anniversary meeting on November 30th.




CHAPTER XI.

DAVY AND THE ROYAL SOCIETY--HIS LAST DAYS.


Davy was elected into the Royal Society in 1803. His certificate
describes him as “a gentleman of very considerable scientific
knowledge, and author of a paper in the Philosophical Transactions.”
Two years afterwards--that is, in his twenty-seventh year--he was
awarded the Copley medal; from which we may infer either that the
Society considered their medal not to have the lustre it now possesses,
or that they had a confident belief in the power and coming greatness
of the recipient, since the papers for which it was given are perhaps
the least meritorious of Davy’s productions. His active interest in
the affairs of the Society led to his election--or rather selection,
for the appointment in those days was made by the President--as one of
the Secretaries, a position he held until 1812, when he resigned it at
the time of his marriage. In 1816 he received the Rumford medal of the
Society for his work in connection with flame and the safety lamp--an
award which would have given a peculiar satisfaction to Rumford had he
lived to witness it.

On the death of Sir Joseph Banks the general voice of the Fellows
seemed to designate Wollaston as his successor. It was, indeed, Sir
Joseph Banks’s desire that Dr. Wollaston should be nominated. “So
excellent a man,” he remarked to Barrow, “of such superior talents,
and everyway fitted for the situation. Davy is a lively and talented
man, and a thorough chemist; but ... he is rather too lively to fill
the chair of the Royal Society with that degree of gravity which
it is most becoming to assume.” Oh this gravity! “La gravité,” says
La Rochefoucauld, “est un mystère du corps, inventé pour cacher les
défauts de l’esprit.” And Sir Joseph had enough of it and to spare.
Wollaston--a man of wide knowledge, steady, cautious, and sure,--of
cool judgment and sagacious views, as Davy said of him--felt no
inclination to accept a position for which his retiring habits and
reticent disposition to some extent unfitted him, and he declined to be
put in nomination. Davy’s attitude is indicated in the following letter
to his friend Poole:--

    “I feel that the President’s chair, after Sir Joseph, will
    be no light matter; and unless there is a strong feeling in
    the majority of the body that I am the most proper person, I
    shall not sacrifice my tranquillity for what cannot add to my
    reputation, though it may increase my power of being useful.

    “I feel it a duty that I owe to the Society to offer myself;
    but if they do not feel that they want me, (and the most active
    members, I believe, do) I shall not force myself upon them.”

The “strong feeling in the majority” was shown on the day of election.
A few votes were given in favour of Lord Colchester, but Davy’s triumph
was practically complete.

He thus writes to Mr. Poole in answer to a letter of congratulation:--

    “I have never needed any motive to attach me to science, which I
    have pursued with equal ardour under all circumstances, for its
    own sake, and for the sake of the public, uninfluenced by the
    fears of my friends, or the calumnies of my enemies. I glory in
    being in the chair of the Royal Society, because I think it ought
    to be a reward of scientific labours, and not an appendage to
    rank or fortune; and because it will enable me to be useful in a
    higher degree in promoting the cause of science.”

Davy was re-elected to the Presidential Chair without opposition for
seven successive years--until, in short, his failing health compelled
him to resign. Although the Society owes much to him, he himself
derived little satisfaction or pleasure from the position. He soon
found, as he anticipated, that the President’s Chair, after Sir Joseph,
was no light matter; and there is little doubt that the worries and
cares of the office contributed to his untimely death. In bearing,
manner, temperament--in fact, in almost every particularity--he was
the very opposite to his predecessor; and when the discontent which
had slumbered, with an occasional awakening, during Sir Joseph’s long
reign, and which his firmness, tact, and the weight of his personal
character had for the time allayed, broke out, Davy was too impulsive
and irascible to deal with it as Banks had done, and matters which a
less sensitive or a more impassive man would have unheeded were causes
of annoyance and ill-temper to him, and served to add to the spirit of
disunion which prevailed. But if he occasionally lacked discretion,
he was never wanting in zeal. He laboured incessantly to add to the
dignity and usefulness of the Society. He strove in every way to
enhance the character of its publications and to raise the standard
of Fellowship. His great ambition was to bring the Society into more
intimate relation with the State.

    “It was his wish,” says his brother, “to have seen the Royal
    Society an efficient establishment for all the great practical
    purposes of science, similar to the college contemplated by Lord
    Bacon, and sketched in his New Atlantis; having subordinate to
    it the Royal Observatory at Greenwich for astronomy; the British
    Museum, for natural history, in its most extensive acceptation.”

Realising in his own case what such a laboratory as that of the Royal
Institution, supported wholly by private liberality, had done for
science, it was his desire that similar laboratories, amply provided
with all means requisite for original inquiry, should be maintained and
administered by the Society. But, as his brother adds, the Government,
although ready enough to consult him when in want of his knowledge or
of that of other Fellows of the Society, was lukewarm and indifferent
in matters of science, and he received no effectual support. It is true
that towards the end of his Presidency the Society received a mark of
Royal favour by the foundation of the Royal Medals in 1825, but from
various causes the medals were not actually forthcoming until 1833,
when the Duke of Sussex was in the Chair, although no fewer than ten
awards had been made in the meantime. In his attention to the personal
duties of his office Davy was unremitting. His addresses were a feature
of the session; in these he displayed all the ardour, eloquence
and poetical fervour, and, it may be added, all the egoism, which
characterised his lectures. He delighted to dwell upon the power and
dignity of science, its worth as a mental instrument, and its value to
the national life. In his announcements of the awards of the Society’s
medals the range of his knowledge, his power of exposition, and his
faculty of felicitous expression found ample opportunity for exercise.
He was the first President to introduce obituary notices of Fellows,
and his _éloges_ are marked by judgment, taste, and warmth of feeling.

In everything that related to the dignity and ceremony of his office he
was, as might have been expected, most punctilious. Although as a rule
somewhat careless in dress, he invariably took the chair in full Court
dress, sitting covered, and with the mace of office--the veritable
“bauble” which Cromwell ordered to be removed from the table of the
House of the Commons--in front of him, as is still the custom.

To enhance his dignity we are told that he petitioned Government for
the Red Ribbon of his predecessor, and it was said that he felt so
certain his request would be granted that his name was printed with the
coveted letters K.B. appended.

During the session he followed the practice of Sir Joseph Banks in
assembling the Fellows at a weekly conversazione at his house in
Lower Grosvenor Street. Subsequently, on his removal to Park Street,
these meetings were held in the apartments of the Society at Somerset
House. Davy’s vivacity and conversational powers made the gatherings
in the outset a great success, but when the tide of his unpopularity
as President set in, the attendance fell off, and they were eventually
discontinued.

During the autumn preceding his first election he spent some time with
Scott at Abbotsford, in company with Wollaston and Mackenzie (the
Man of Feeling), and Lockhart gives some account of him as the party
started on a sporting expedition on a September morning.

    “But the most picturesque figure was the illustrious inventor
    of the safety lamp. He had come for his favourite sport of
    angling ... and his fisherman’s costume--a brown hat with
    flexible brims, surrounded with line upon line, and innumerable
    fly-hooks; jack-boots worthy of a Dutch smuggler, and a fustian
    surtout dabbled with the blood of salmon--made a fine contrast
    to the smart jackets, white-cord breeches, and well polished
    jockey-boots of the less distinguished cavaliers about him. Dr.
    Wollaston was in black, and with his noble serene dignity of
    countenance might have passed for a sporting archbishop.... I
    have seen Sir Humphry in many places, and in company of many
    different descriptions; but never to such advantage as at
    Abbotsford. His host and he delighted in each other, and the
    modesty of their mutual admiration was a memorable spectacle.
    Davy was by nature a poet--and Scott, though anything but a
    philosopher in the modern sense of that term, might, I think it
    very likely, have pursued the study of physical science with zeal
    and success, had he happened to fall in with such an instructor
    as Sir Humphry would have been to him, in his early life. Each
    strove to make the other talk--and they did so in turn more
    charmingly than I have ever heard either on any other occasion
    whatsoever. Scott in his romantic narratives touched a deeper
    cord of feeling than usual, when he had such a listener as Davy;
    and Davy, when induced to open his views upon any question of
    scientific interest in Scott’s presence, did so with a degree
    of clear energetic eloquence, and with a flow of imagery and
    illustration, of which neither his habitual tone of table-talk
    (least of all in London), nor any of his prose writings (except,
    indeed, the posthumous Consolations in Travel) could suggest an
    adequate notion. I say his prose writings--for who that has read
    his sublime quatrains on the doctrine of Spinoza can doubt that
    he might have united, if he had pleased, in some great didactic
    poem, the vigorous ratiocination of Dryden and the moral majesty
    of Wordsworth? I remember William Laidlaw whispering to me, one
    night, when their ‘wrapt talk’ had kept the circle round the fire
    until long after the usual bed-time of Abbotsford--‘Gude preserve
    us! This is a very superior occasion! Eh, sirs!’ he added,
    cocking his eye like a bird, ‘I wonder if Shakspeare and Bacon
    ever met to screw ilk other up?’”

In spite of the many calls upon his time and energies entailed by
his duties as President, he still found opportunity to work in his
laboratory, and one outcome of his labours was a paper “On the magnetic
phenomena produced by electricity,” published in the _Philosophical
Transactions_ for 1821--the sequel of a letter addressed to Wollaston
and also printed in the Transactions. This memoir was followed a few
months later by a communication “On the Electrical phenomena exhibited
_in vacuo_.”

These papers, together with one on a New Phenomenon of
Electro-Magnetism, published in 1823, are interesting in relation to
the development of Oersted’s great discovery, and in connection with
the subsequent work of Faraday.

With that power of generalisation which is one of the distinguishing
marks of his genius, he shows the possible connection of the facts he
had observed with the phenomena of terrestrial magnetism. He concludes
his first paper by asking

    “whether the magnetism of the earth may not be owing to its
    electricity, and the variation of the needle to the alterations
    in the electrical currents of the earth, in consequence of its
    motions, internal changes, or its relations to solar heat; and
    whether the luminous effects of the auroras at the poles are not
    shown, by these new facts, to depend on electricity. This is
    evident, that if strong electrical currents be supposed to follow
    the apparent course of the sun, the magnetism of the earth ought
    to be such as it is found to be.”

It is perhaps idle to speculate on such a matter, but it is more than
likely that had Davy been free from the cares and restraints of office,
and from the innumerable distractions inseparable from his position in
the social and scientific world of London, he might have revealed the
possibilities in electro-magnetism with the same brilliant success as
he had done those of voltaic electricity. He was now at the maturity
of his mental power, and had still much of the enthusiasm and ardour
which characterised his earliest work, and under serener conditions
he might have achieved triumphs not less striking than those reserved
for Faraday. His few short papers on the subject indicate that he
fully realised the great wealth of the new territory thus opened out
to science, and into which he was one of the first to penetrate. But
it is sad to think that he might have extended a more generous hand to
one who, equally with himself, was striving to enter the new land, and
who eventually did enter and for a time possessed it. In the concluding
words of Davy’s last paper on electro-magnetism, we discern in the
allusion to Wollaston’s idea of the possibility of the rotation of the
electro-magnetic wire round its axis “the rift within the lute” in his
relations towards his assistant, which widened in the matter of the
condensation of chlorine, and which threatened to become an open breach
when Faraday was elected into the Royal Society.

The jealousy thus manifested by Davy is one of the most pitiful facts
in his history. It was a sign of that moral weakness which was at
the bottom of much of his unpopularity, and which revealed itself in
various ways as his physical strength decayed.

Greedy as he was of fame--that infirmity of noble minds--many incidents
in his life up to this period prove that he was not wanting on occasion
in a generous appreciation of the work of his contemporaries, even
in fields he might reasonably claim as his own. But, although in
his intellectual combats he could show at times a certain knightly
courtesy, it must be confessed that he was lacking in the magnanimity
which springs from the charity that envieth not.

In genius he was unquestionably superior to Faraday; in true nobility
of character he was far below him. It is almost impossible to avoid
comparing him with Faraday. Indeed it is one of the penalties of his
position that he has to be tried by so severe a standard, and it
may well be that his good name, which, as Bacon says, is the proper
inheritance of the deceased, has suffered unduly in consequence. His
true place in the history of science is defined by his discoveries;
it is a sad reflection that the lustre of his fame has been dimmed
rather than heightened by what has been styled the greatest of them
all--Faraday. But there has undoubtedly been injustice in the
comparisons which have been made. What Davy was to Faraday, Faraday
would have been the first to admit. Davy made himself what he was by
the sheer force of his unaided genius; what Faraday became was in large
measure due to his connection with Davy, and the germs of his greatest
works are to be traced to this association. This fact has been frankly
acknowledged by Faraday. To the end of his days he regarded Davy as his
true master, preserving to the last, in spite of his knowledge of the
moral frailties of Davy’s nature, the respect and even reverence which
is to be seen in his early lecture notes and in his letters to his
friend Abbott. Faraday was not easily roused to anger, but nothing so
effectually moved him as any aspersion of Davy’s character as a man of
science, or any insinuation of ungenerous treatment of himself by Davy.

At about this time--that is, in the autumn of 1823--Davy gave the first
signs of the obscure malady which ultimately occasioned his death. In
a letter to his brother, in which he describes his symptoms, we have a
reference, also, to his domestic worries: “To add to my annoyances, I
find my house, as usual, after the arrangements made by the mistress of
it, without female servants; but in this world we have to suffer and
bear, and from Socrates down to humble mortals, domestic discomfort
seems a sort of philosophical fate.”

He was able, however, to continue his scientific work, but instead of
the fame and applause on which he so confidently counted, he found only
disappointment and chagrin.

In 1823 the Admiralty sought the advice of the Royal Society as to
“the best means of securing to the service copper of the most durable
quality, and such as will preserve the smoothest surface.” A committee
of the Society was appointed, under Davy’s direction, to consider the
question, which ultimately resolved itself into one of preventing
the corrosion of the metal. In this matter Davy’s special experience
proved most useful, and, as a fact, he took all the experimental part
of the inquiry upon himself, and with what result may be seen from the
following letter to his brother:--

            “Firle, Jan'y 30, 1824.

    “I have lately made a discovery of which you will for many
    reasons be glad. I have found a complete method of preserving the
    copper sheeting of ships, which now readily corrodes. It is by
    rendering it negatively electrical. My results are of the most
    beautiful and unequivocal kind: a mass of tin renders a surface
    of copper 200 or 300 times its own size sufficiently electrical
    to have no action on sea water.

    “I was led to this discovery by principle, as you will easily
    imagine; and the saving to government and the country by it
    will be immense. I am going to apply it immediately to the
    navy. I might have made an immense fortune by a patent for this
    discovery, but I have given it to my country; for in everything
    connected with interest, I am resolved to live and die at least
    ‘_sans tâche_.’”

His method of rendering the copper negatively electric consisted in
affixing to the sheets a number of short bars of iron or zinc, properly
curved to the shape of the vessel. In this way the “protectors,” as the
zinc or iron bars were called, gradually corroded, whilst the copper
remained unattacked. But, as Dr. Paris remarks, the truth of the theory
was completely established by the failure of the remedy. The ship’s
bottom became so foul by the adhesion of shells and weed that her speed
was greatly impeded, and after a number of trials, in the course of
which a steam vessel was placed at his disposal, in which he made a
voyage to Norway and back, the Admiralty directed the protectors to be
removed. To add to his mortification, the order was issued immediately
after a communication to the Royal Society announcing the complete
success of his plan. Throughout the whole of this business he was
exposed to a number of vexatious attacks, which greatly embittered him
and reacted disastrously upon his health and character. So long as
there was the hope of success and the prospect of reward his claims
to the originality of the invention were contested: no sooner was the
project abandoned than he was assailed in the periodical press and made
an object of sarcasm and censure. As might be imagined, his philosophy
was not proof against such attacks. He wrote to his friend Children--

    “A mind of much sensibility might be disgusted, and one might be
    induced to say why should I labour for public objects, merely to
    meet abuse?--I am irritated by them more than I ought to be; but
    I am getting wiser every day--recollecting Galileo, and the times
    when philosophers and public benefactors were burnt for their
    services.”

During the autumn his indisposition increased, and his home letters
show that the wonderful elasticity of spirit, which, as his brother
remarks, had hitherto carried him lightly and joyously through life,
over all its rubs and cares, now seemed to flag. He had an ailing
winter, and with the spring came news of his mother’s illness. He could
only write with difficulty:--“If it please God, I will certainly be at
Penzance the last week in October or the first in November.” He never
saw her again; she rallied for a time, but died somewhat suddenly in
September. Davy never really recovered from the shock of her death. It
was with the greatest difficulty that he was able to preside at the
anniversary meeting of the Society on the ensuing St. Andrew’s Day. The
effort was so marked that those near him feared he was on the verge of
apoplexy, and he was too ill to attend the dinner. A few weeks later he
had a slight attack of paralysis, from which he only slowly recovered.
His good friend Dr. Babington[J] ordered him abroad, away from “the
convivial epicurean habits of London society,” and from “the many
annoyances and causes of injurious excitement to which he was exposed
at home.” He set out with his brother John, in the depth of winter--“a
dreary beginning of a dreary journey.” He avoided Paris; he would not
even pass through it, so apprehensive was he that he should not escape
from “the allurement--or, rather, excitement--of its society” if he
stopped there. The roads were in a wretched state, the country covered
with snow, and “no object to arrest the eye, except a village here and
there rising out of the white waste, or a distant steeple, or some
solitary tree.” The cold was intense, and once or twice the travellers
were benighted, the wheels of their carriage being locked in the frozen
ruts. As they passed through the towns Davy, who seemed to cling to
life with a passionate tenacity, would visit the churches, and, falling
on his knees, would offer up a silent prayer. They crossed Mont Cenis
in a storm of wind and amidst drifting snow, and with great difficulty
got down to Susa on sledges. The snow in Lombardy was deeper than in
the passes of the Alps, and even at Ravenna, where they arrived in the
first week of March, it was still to be seen in the ditches. Here his
brother left him, his duties as an army surgeon calling him to Corfu.
In spite of severe weather, the discomforts of travelling at such a
time, and the forced delays at wretched inns, Davy gradually improved;
his brother noted before he left that he was certainly stronger, less
paralytic, and more active. He wrote to his friend Poole:--

    [J] “Babington, the best and warmest-hearted friend, the
        kindest husband and father, and perhaps the most
        disinterested physician of his time; with good talents, and
        a fine tact, and a benevolence which created sympathy for
        him wherever he appeared, and I believe often cured his
        patients.”

    “I am, thank God, better, but still very weak, and wholly unfit
    for any kind of business and study. I have, however, considerably
    recovered the use of all the limbs that were affected; and as my
    amendment has been slow and gradual, I hope in time it may be
    complete. But I am leading the life of an anchorite, obliged to
    abstain from flesh, wine, business, study, experiments, and all
    things that I love; but this discipline is salutary, and for the
    sake of being able to do something more for science, and I hope
    for humanity, I submit to it, believing that the Great Source of
    intellectual being so wills it for good.”

He tells Poole that he had chosen Ravenna--this spot of the declining
Empire of Rome--as one of solitude and repose, and as out of the way of
travellers and in a good climate. He was interested, too, in its many
associations with his friend Byron, with Dante, and in its old-world
memories of Theodoric and his lost legions. How the place affected him
in his state of physical enfeeblement, but with his mind chastened and
purified, may be seen in the character of much that he wrote there, and
particularly in his poems, with their many notes of sadness and hope,
trust and resignation. He was lodged in the Apostolical Palace by the
kindness of the Vice-Legate--a graceful, learned, and accomplished man,
with whom he contracted a warm friendship. He says he could not speak
of his goodness without tears of gratitude in his eyes, and with this
exception and an occasional visit from the Countess Guiccioli he had
no society. Most of his time was spent in riding amidst the pines and
junipers, or following the petzardone among the marshes of La Classe;
or in reading and in the study of natural history.

    “The natural strength of his mind,” says his brother, “was very
    clearly manifested under these circumstances. Dependent entirely
    on his own resources; no friend to converse with; no one with
    him to rely on for aid, and in a foreign country, without even
    a medical adviser; destitute of all the amusements of society;
    without any of the comforts of home--month after month, he kept
    on his course, wandering from river to river, from one mountain
    lake and valley to another, in search of favourable climate;
    amusing himself with his gun and rod, when sufficiently strong to
    use them, with ‘_speranza_’ for his rallying word.”

With the approach of spring he passed by way of Gorizia into Illyria,
and, as the heat increased, into Upper Austria, Bavaria, and
Switzerland, and back, in the late summer, to Illyria. His journals
give a fairly full account of his movements and of the manner in
which he spent his time; they also indicate his state of mind, the
alternations of hope and despondency, and his constant struggles with
the insidious disease which was gradually exhausting his physical
powers.

He wrote to his wife from Laybach:--

    “You once _talked_ of passing _this_ winter in Italy; but I
    hope your plans will be entirely guided by the state of your
    health and feelings. Your society would undoubtedly be a very
    great resource to me, but I am so well aware of my own present
    unfitness for society, that I would not have you risk the chance
    of an uncomfortable moment on my account. I often read Lord
    Byron’s _Euthanasia_: it is the only case, probably, where my
    feelings perfectly coincide with what his were.”

At times the feeling of despair was so intense that he actually seemed
apprehensive of suicide. It was probably under the influence of such
a fear that he wrote in his journal that he had too strong a faith
in the optimism of the system of the universe ever to accelerate his
dissolution.

    “I have been and am taking a care of my health which I fear it is
    not worth; but which, hoping it may please Providence to preserve
    me for wise purposes, I think it my _duty_.”

On another occasion he wrote to Lady Davy:--

    “I am glad to hear of your perfect re-establishment, and with
    health and the society of London, which you are so well fitted to
    ornament and enjoy, your ‘_viva la felicità_’ is much more secure
    than any hope belonging to me.”

Subsequently he wrote:--

    “Should your feelings or inclination lead you _to the land of the
    sun_, I need not say what real pleasure it would give me to enjoy
    your society; but do not make any sacrifice on my account.”

A couple of days afterwards he wrote:--

    “I hope I shall have the delight of seeing you at Baden Baden. If
    not, I shall come to England.... Pray let my physicians know what
    an obedient patient I am.... God bless you, my dear Jane!”

Towards the end of September, and at Baden, the solitary man wrote:--

    “I fear my light of life is burnt out, and that there remains
    nothing but stink, and smoke and dying snuff.... _Dubito
    fortissime restaurationem meum._--Decidedly worse and have
    decided to go home immediately.”

At Mayence he informed his wife that he trusted soon to see her in Park
Street. He had a lingering hope that she might still be induced to
cross the water, and that he might meet her at Calais.

    “I think you will find me altered in many things--with a heart
    still alive to value and reply to kindness, and a disposition to
    recur to the brighter moments of my existence of fifteen years
    ago, and with a feeling that though a burnt-out flame can never
    be rekindled, a smothered one may be.... I hope it is a good omen
    that my paper by accident is _couleur de rose_.”

He had previously determined to resign the chair of the Royal Society,
and announced his decision in a letter to his old friend Davies
Gilbert, the treasurer. To his wife he wrote:--

    “If I had perfectly recovered I know not what I should have
    done with respect to the P. under the auspices of a new and
    more enlightened government; but my state of health renders the
    resignation _absolutely_ necessary. To attempt business this year
    would be to prepare for another attack.”

He is pleased with the idea that Sir Robert Peel, who had “no
scientific glory to awaken jealousy,” may be his successor; and he
resumes:--

    “The prosperity of the Royal Society will always be very dear
    to me, and there is no period of my life to which I look back
    with more real satisfaction than the six years of labour for
    the interests of that body. I never _was_, and never could be,
    unpopular with the active and leading members, as six unanimous
    elections proved; but because I did not choose the Society to be
    a tool of Mr. ----’s journal jobs, and resisted the admission of
    improper members, I had some enemies, who were listened to and
    encouraged from Lady ----’s chair. I shall not name them, but as
    Lord Byron has said ‘my curse shall be forgiveness.’”

He arrived in London in the first week in October, and towards the end
of the month he wrote to his friend Poole that he had consulted all the
celebrated men who had written upon or studied the nervous system.

    “They all have a good opinion of my case, and they all order
    absolute repose for at least twelve months longer, and will not
    allow me to resume my scientific duties or labours at present;
    and they insist upon my leaving London for the next three or four
    months and advise a residence in the West of England.”

Poole promptly asked him down to Nether Stowey. His friend relates
that although his bodily infirmity was very great and his sensibility
painfully acute--(“Here I am, the ruin of what I was!” he exclaimed
on his arrival)--his mind still showed much of its wonted ardour
and vigour. He spent his mornings in literary work, mainly on his
“Salmonia; or, Days of Fly-fishing,” a philosophical disquisition on
angling, published in 1828, and which, despite the rollicking banter of
Christopher North, passed through five or six editions. Davy had the
ambition to do for fly-fishing what Walton had done for the humbler
art of bottom-fishing. But Davy’s book, although constructed on much
the same lines as “The Compleat Angler,” lacks every feature which has
made honest Izaak’s work immortal--the quaint simplicity, the homely
wit, the delicate humour, the delightful charm--the reflection, in a
word, of the mental features of a lovable man blessed with the ornament
of a meek and quiet spirit. The egotism and garrulity of Piscator
are delicious; the loquacity and self-confidence of Davy’s Halieus
are tiresome to the last degree. We are bored with his long didactic
speeches, his consciousness of superiority, and his cheap and tawdry
sentiment. It was a poor return for all the kindness and skill of
Babington, that his patient should have seen in such a creation the
character of one of the most charming and estimable of men.

More than one mention has been made in this biography of what Maria
Edgeworth termed Davy’s “little madness.” Indeed, the love of angling
amounted to a passion with him; and he told Ticknor that he thought
if he were obliged to renounce either fishing or philosophy he should
find the struggle of his choice pretty severe. Whenever he could escape
from town he would hie him to some favourite stream and spend the
day in the practice of his beloved art. He was known to have posted
a couple of hundred miles for the sake of a day’s fishing, and to
have returned contented, although he had never a rise. When confined
to Albemarle Street, and chafing at his inability to get away, he
would sometimes turn over the leaves of his fly-book and derive much
consolation from the sight of his hackles and harles, his green-tails,
dun cuts, red spinners, and all the rest of the deadly paraphernalia
associated in his mind with the memories of pleasant days and exciting
combats. He greatly prided himself on his skill, and his friends were
often secretly amused to notice his ill-concealed chagrin when a
brother-angler outvied him in the day’s catch or in the narration of
some piscatorial triumph. They were amused, too, at the costume which
he was wont to don on such occasions--his broad-brimmed, low-crowned
hat, lined with green and garnished with flies; his grey-green jacket,
with a multitude of pockets for the various articles of his angling
gear; his wading-boots and knee-caps--all made up an attire as original
as it was picturesque. In these fishing expeditions he enjoyed some of
the happiest hours of his life; at such times he threw off his cares
and annoyances; he was cheerful even to hilarity, and never was his
conversation more sprightly or more entertaining.

In spite of the thoughtful care of his friend Poole, Davy’s health
showed no material improvement, and at times his feeling of despondency
was very great. His confidence in his mental powers, however, never
forsook him. He said on one occasion:--

    “I do not wish to live, as far as I am personally concerned; but
    I have views which I could develope, if it please God to save my
    life, which would be useful to science and to mankind.”

       *       *       *       *       *

    “His inherent love of the laboratory (if I may so speak),” says
    Mr. Poole, “was manifested in a manner which much interested
    me at the moment. On his visiting with me a gentleman in this
    neighbourhood who had offered to let him his house, and who has
    an extensive philosophical apparatus, particularly complete in
    electricity and chemistry, he was fatigued by the journey; and as
    we were walking round the house very languidly, a door opened,
    and we were in the laboratory. He threw his eyes round the room,
    which brightened in the action--a glow came over his countenance,
    and he appeared himself twenty years ago. He was surprised and
    delighted and seemed to say, ‘This is the beloved theatre of my
    glory.’ I said ‘You are pleased.’ He shook his head and smiled.”

In the spring he determined to quit England for his beloved Illyria,
and towards the end of May arrived by easy stages at Wurzen. In his
journal he wrote:--

    “May 22. To my old haunt, Wurzen, which is sublime in the majesty
    of Alpine grandeur; the snowy peaks of the Noric Alps rising
    above thunder clouds, whilst spring in all its bloom and beauty
    blooms below; its buds and blossoms adorning the face of Nature
    under a frowning canopy of dark clouds, like some Judith beauty
    of Italy--a Transteverene brow and eye, and a mouth of Venus and
    the Graces.”

From Aussee he wrote to his brother:--

    “It suits me better to wile away my days in this solitary state
    of existence, in the contemplation of Nature, than to attempt to
    enter into London society, where recollections call up the idea
    of what I was, and the want of bodily power teaches me what a
    shadow I am.... I am now going to Ischl, where there are warm
    salt baths to try if they will renovate the muscular powers of my
    arm and leg.... I wish to go to Trieste in October, to make the
    experiments I have long projected on the torpedo.”

He derived some little benefit from the treatment at Ischl, and in
October went to Trieste, where he carried out his projected experiments
on the electricity of the torpedo, the results of which he communicated
to the Royal Society. This paper was the last of his scientific
memoirs. In the middle of November he arrived at Rome, where he learnt
that Wollaston also had been stricken with paralysis.[K] On February
6th, 1829, he wrote to Poole:--

    [K] He died on December 22nd, 1828.

    “I am here _wearing away_ the winter,--a ruin amongst ruins!
    ... I hope you got a copy of my little trifle ‘Salmonia.’... I
    write and philosophise a good deal, and have nearly finished a
    work with a higher aim than the little book I speak of above,
    which I shall dedicate to you. It contains the essence of my
    philosophical opinions, and some of my poetical reveries. It is
    like the ‘Salmonia,’ an amusement of my sickness; but ‘_paulo
    majora canamus_.’ I sometimes think of the lines of Waller, and
    seem to feel their truth--

       ‘The soul’s dark cottage, batter’d and decay’d,
        Lets in new light through chinks that Time has made.’”

The work to which he here alludes, and which he did not live to see
printed, was his “Consolations in Travel; or, The Last Days of a
Philosopher.” He had practically finished it at the date of his letter,
and had written in his journal: “Si moro, spero che ho fatto il mio
dovere, e che mia vita, non e stato vano ed inutile.” On February
20th he was seized with a new attack, and his right side was quite
powerless. On the 23rd he dictated the following letter to his brother,
who was then at Malta:--

    “Notwithstanding all my care and discipline, and ascetic living,
    I am dying from a severe attack of palsy, which has seized the
    whole of the body with the exception of the intellectual organ
    ... the weakness increases and a few hours or days will finish
    my mortal existence. I shall leave my bones in the Eternal City.
    I bless God that I have been able to finish all my philosophical
    labours.... I hope you will have the goodness to see these works
    published.... I have given you, by a codicil to my will, the
    copyright of these books.... God bless you, my dear John! May you
    be happy and prosperous!”

The letter was signed by him, and he added in his own handwriting, only
just legible, “Come as quickly as possible.”

Two days afterwards he dictated another letter, in which he gives
minute directions concerning some experiments on the torpedo which he
wished his brother to make. He describes the apparatus which may be
employed and indicates where the torpedoes may be procured, and he
concludes: “Pray do not neglect this subject, which I leave to you as
another legacy.” It was the 16th of March before Dr. Davy could reach
Rome. The stricken man’s pale and emaciated countenance lighted up
as he saw his brother at his bedside. He spoke as if he had only a
few hours to live, and rejected all expectation and hope of recovery,
saying he was sure his career was run.

Under the care and medical skill of Dr. Davy, however, he rallied.

    “As he mended,” says his brother, “the sentiment of gratitude
    to Divine Providence was overflowing, and he was most amiable
    and affectionate in manner. He often inculcated the propriety,
    in regard to happiness, of the subjugation of self, in all
    selfishness, as the very bane of comfort, and the most active
    cause of the dereliction of social duties, and the destruction
    of good and friendly feelings; and he expressed frequently the
    intention, if his life were spared, of devoting it to purposes of
    utility (seeming to think lightly of what he had already done),
    and to the service of his friends, rather than to the pursuits
    of ambition, pleasure, or happiness, with himself for their main
    object.”

But, Dr. Davy adds:--

    “Now that he was intent on recovery, he no longer took the same
    interest in _my_ examination of the torpedo, as if he looked
    forward to the time when _he_ should be able to enter into the
    investigation actively again.”

At the beginning of April Lady Davy arrived from England, and he
had so far improved that it was decided to remove him to Geneva.
By easy stages, and occasional halts of two or three days at the
more interesting places, he arrived at Geneva on May 28th. He bore
the journey well: the delightful freshness of the spring, the
bursting vegetation, the many streams, the pure mountain air, and the
indescribable influence of Alpine scenery, seemed to invigorate him.
On his arrival at the inn (“La Couronne”) he walked to the window,
looked out upon the lake, and expressed a longing wish to throw a fly
upon its blue waters. Lady Davy here broke to him the news of the
death of his old friend and colleague, Thomas Young. This, coming so
soon after the loss of Wollaston, profoundly affected him. During the
evening he struck his elbow against the projecting arm of the sofa on
which he sat; the blow gave him great pain, and seemed to have the most
extraordinary effect. He was got to bed as soon as possible. He took an
anodyne, and desired to be left alone. Soon after midnight he was found
to be insensible, and shortly before three on the morning of the 29th
of May he died. In his will he had enjoined that he should be buried
where he died: _Natura curat suas reliquias_, he had written.

The City gave him a public funeral, and representatives of every
institution in the town followed his remains to their resting-place in
the cemetery at Plain-Palais. A simple monument, with the following
inscription, marks the spot:--

                               HIC JACET
                              HUMPHRY DAVY
                    EQUES MAGNÆ BRITANNIÆ BARONETUS
                   OLIM REGIÆ SOCIET. LONDIN. PRÆSES
                   SUMMUS ARCANORUM NATURÆ INDIGATOR.
         NATUS PENZANTIÆ CORNUBIENSUM XVII DECEMB. MDCCLXXVIII.
              OBIIT GENEVÆ HELVETIORUM XXIX MAI MDCCCXXIX.

His widow placed a tablet to his memory in the north transept of
Westminster Abbey. His baronetcy died with him. By his will he directed
that the service of plate given to him by the coal-owners should, after
Lady Davy’s death, pass to his brother, and that in the event of his
having no heirs in a position to make use of it, it should be melted
and given to the Royal Society, “to found a medal to be given annually
for the most important discovery in chemistry anywhere made in Europe
or Anglo-America.” This is the origin of the Davy Medal which has been
awarded annually by the Society since 1877.

Many eloquent tributes have been paid to the genius and labours of
Davy, and some of these eulogies are among the most brilliant passages
in the literature of science. One of the best-known is from the gifted
pen of Dr. Henry in the preface to his “Elements of Chemistry,”
published soon after Davy’s death. He thus sketches the more striking
characteristics of the great chemist.

    “Davy,” he says, “was imbued with the spirit, and was a master of
    the practice, of the inductive logic; and he has left us some of
    the noblest examples of the efficacy of that great instrument of
    human reason in the discovery of truth. He applied it not only to
    connect classes of facts of more limited extent and importance
    but to develope great and comprehensive laws, which embrace
    phenomena that are almost universal to the natural world. In
    explaining these laws, he cast upon them the illuminations of his
    own clear and vivid conceptions;--he felt an intense admiration
    of the beauty, order and harmony which are conspicuous in the
    perfect chemistry of Nature;--and he expressed these feelings
    with a force of eloquence which could issue only from a mind of
    the highest powers and of the finest sensibilities.”

Not less forcible or eloquent, although hardly so well known, is the
estimate in Silliman’s _American Journal of Science and Arts_ for
January, 1830. After an analysis, of Davy’s mental attributes the
writer concludes:--

    “We look upon Sir Humphry Davy as having afforded a striking
    example of what the Romans called _a man of good fortune_;--whose
    success, even in their view, was not however the result of
    accident, but of ingenuity and wisdom to devise plans, and of
    skill and industry to bring them to a successful issue. He
    was fortunate in his theories, fortunate in his discoveries,
    and fortunate in living in an age sufficiently enlightened to
    appreciate his merits;--unlike, in this last particular, to
    Newton, who (says Voltaire), although he lived forty years
    after the publication of the _Principia_, had not, at the time
    of his death, twenty readers out of Britain. Some might even
    entertain the apprehension that so extensive a popularity among
    his contemporaries is the presage of a short-lived fame; but his
    reputation is too intimately associated with the eternal laws
    of Nature to suffer decay; and the name of Davy, like those of
    Archimedes, Galileo and Newton, which grow greener by time, will
    descend to the latest posterity.”

Such, then, is the story of a life of fruitful endeavour and splendid
achievement;--the record of one who, if not wholly good or truly noble,
has left a track of greatness in his passage through the world.




INDEX.


  Address from Whitehaven colliers to Davy, 203

  Agriculture, Davy’s lectures on, 94 _et seq._; 165

  Alkali metals, Isolation of, 114, 116;
    their properties, 118

  Alkaline earths, Decomposition of, 126

  Ammonia: Davy’s conjectures as to its nature, 121

  Ammonium amalgam: Davy’s views as to its nature, 127

  Ammonium nitrate, Modes of decomposition of, 43

  “Annual Anthology, The,” 18, 57

  Apreece, Mrs., 159, 162


  Babington, Dr., his character, 224

  Bakerian lecture, Origin of, 100

  Banks, Sir Joseph, his opinion of the Royal Institution, 80;
    his account of Davy’s courtship, 162;
    his opinion of Davy, 213;
    death of, 212

  Beddoes, Mrs., 28

  ----, Thomas, 23;
    letters to Davies Gilbert, 24, 25;
    engages Davy as chemist to the Pneumatic Institution, 25;
    his testimony to Davy’s originality, 32;
    his end, 65

  Bernard, Thomas, 66, 67, 80

  Berthollet, Davy’s account of, 179;
    his theory of the nature of chlorine, 136, 144

  Berzelius, Jakob, 94, 109, 143, 154

  Bonaparte’s medal for discoveries in galvanism awarded to Davy, 109

  Borlase, Bingham, 15, 25

  Boron, Isolation of, 129

  Brande, William Thomas, succeeds Davy as Professor of Chemistry in
          the Royal Institution, 176

  Brownrigg, Lady, her account of Davy, 111

  Buddle, John, 194, 195, 201, 204, 209;
    letter to Davy, 201


  Cardew, Dr., Master of Truro Grammar School, his opinion of Davy as
          a boy, 12

  Chlorine, Discovery of, by Scheele, 136;
    its nature, 134 _et seq._;
    controversy as to its nature, 143;
    its bleaching power explained, 149;
    its liquefaction by Northmore, 149;
    by Faraday, 149

  ---- compounds, Davy’s nomenclature of, 149

  Chlorophosphamide, 138

  Coal-owners’ Testimonial to Davy, 205, 208

  Coleridge, Samuel Taylor, his opinion of Davy, 18, 55, 57, 88;
    letters to Davy, 57, 58, 59;
    letter to Purkis, 88

  Colouring matters of the Ancients, Investigation of, by Davy, 185, 187

  “Consolations in Travel,” 232

  Copley medal awarded to Davy, 213

  Coryton, Mr., Master of Penzance Grammar School, his methods of
          tuition, 12, 13, 53

  Cottle, Amos, his account of Davy, 55

  Cuvier, Davy’s account of, 178


  Davy: His birth, 9;
    becomes chemist to the Pneumatic Institution, 25;
    goes to the Royal Institution, 63;
    his views on the Atomic Theory, 146, 147;
    marriage, 163;
    is knighted, 164;
    is elected a member of the Institute, 179;
    is created a baronet, 211;
    his illness, 221, 224;
    death, 234;
    burial, 234;
    his character, 235, 236;
    as an angler, 158, 159, 229;
    as a lecturer, 71, 73 _et seq._, 84, 86;
    as a man of society, 87, 115;
    as a poet, 17, 18, 19, 125, 179

  Davy’s letters: To Mrs. Apreece, 159, 160, 161;
    to Mr. Children, 168, 223;
    to Lady Davy, 226, 227, 228;
    to Dr. John Davy, 163, 165, 183, 222, 231, 232;
    to Faraday, 174;
    to Mr. Davies Gilbert, 29, 40, 51, 63, 85, 228;
    to Dr. Gray, 195, 197;
    to Rev. Mr. Hodgson, 196;
    to Dr. Hope, 62, 69;
    to his mother, 13, 26, 27, 52, 62, 79, 158, 163, 176, 188, 211, 223;
    to Mr. Poole, 88, 214, 225, 228, 232;
    to his sisters, 116

  ---- nomenclature of chlorine compounds, 149

  Davy medal, The, 235

  ----, Edmund, cousin of Humphry Davy, 114, 123, 133

  ----, Edmund, grandfather of Humphry Davy, 10

  ----, Lady, her character, 189, 190, 191

  ----, Robert, father of Humphry Davy, 9, 10

  Diamond, Davy’s investigation of nature of, 184

  Dibdin, Dr., his address on the occasion of Davy’s illness, 123


  Edgeworth, Maria, her account of the respiratory action of nitrous
          oxide, 41;
    her account of Davy’s visit to Ireland, 112, 158;
    on Mrs. Apreece, 165

  Electro-chemical Theory of Davy, 106

  Electrolytic decomposition of water, Discovery of, by Nicholson and
          Carlisle, 90

  Electro-magnetism, Davy’s contributions to, 218

  “Elements of Chemical Philosophy,” Davy’s, 167

  Euchlorine, 142, 151


  Faraday, Michael, attends Davy’s lectures, 143;
    joins the Royal Institution, 173;
    his letters to Abbott concerning Davy, 188, 189;
    his relations to Davy, 220

  “Fidelissima,” her sonnets to Davy, 78

  Fire-damp explosions, 193

  Flame, Davy’s investigations on, 209

  Fluorine, Attempts to isolate, by Davy, 170

  ---- theory, The, 172 _et seq._

  “Fuming liquor of Cadet,” Davy’s investigation of, 132


  Garnett, Thomas, first lecturer in the Royal Institution, 68

  Gay Lussac, Davy’s account of, 179

  Gilbert, Davies (Davies Giddy), 21, 22

  Gray, Rev. Dr., his association with Davy, 195, 197


  Heat a mode of motion, 32

  “Heat, Light, and the Combinations of Light,” 30, 37

  Hippesley, Sir John, 69, 80

  Hodgson, Rev. Mr., his association with Davy, 194, 196, 201

  Horner, Francis, his opinion of Davy as a lecturer, 77

  Humboldt, Davy’s account of, 178

  Hydrogen chloride, Synthesis of, by Cruickshank, 139


  Iodates, Davy’s investigation of, 184

  Iodine, Discovery of, by Courtois, 180;
    investigation of, by Clement, 180;
    by Davy, 180 _et seq._;
    by Gay Lussac, 180

  Ireland, Davy’s views on, 112;
    his lectures in, 156 _et seq._


  Lavoisier’s “Elements”--character as a text-book, 19

  “Liquor of Libavius,” Action of ammonia on, studied by Davy, 137

  Lockhart’s account of Davy, 110, 217


  Nitrogen believed by Davy to be a compound, 132 _et seq._

  ---- chloride, Investigation of, by Davy, 168;
    its explosion injures Davy, 169

  ---- oxides, Davy’s work on, 42, 45

  Nitrosulphonic acid, 154

  Nitrous oxide, discovery of its respirability, 41, 46, 49;
    composition of, 45;
    effect of breathing, 49


  Oxymuriatic acid, Davy’s memoir on, 134


  Papyri, Davy’s attempts to unroll, 211

  Penzance, State of society in, at close of 18th century, 14

  Phosoxygen, 30, 33, 35, 37

  Phospham, 138

  Phosphorous acid and oxide, 153

  ---- chlorides discovered by Davy, 129, 152;
    action of ammonia on, 137;
    action of water on, 140;
    analysis of, 153

  Pneumatic Institution, Bristol, 23, 27, 29

  Potassamide, Preparation of, 129

  Potassium, Isolation of, 114 _et seq._, 116 _et seq._;
    properties of, 116

  Priestley, Joseph, 38

  Purkis, Mr., his account of Davy’s lectures, 77


  Royal Institution, The, its origin and character, 66, 79;
    its chemical laboratory, 90, 133;
    minutes of Managers, 63, 72, 166, 175, 176

  ---- medals, the, Institution of, 216

  ---- Society, Davy’s election into the, 213;
    becomes Secretary, 112;
    becomes President, 214;
    his views of its functions, 215

  Rumford, his theory of heat, 32;
    founds the Royal Institution, 66;
    visit of Davy to, at Auteuil, 177

  ---- medal awarded to Davy, 213


  Safety lamp, its invention, 192 _et seq._;
    account of, by Playfair, 203

  “Salmonia,” Account of, 229

  Scheele, discoverer of chlorine, 136

  Scott, Sir Walter, his friendship for Lady Davy, 162;
    his friendship for Davy, 217

  Ship-sheathing, Davy’s experiments on, 222

  Silex in plants, 39

  Sodium, Isolation of, 118;
    properties of, 119

  Southey, Robert, his opinion of Davy, 18, 55, 56;
    letter to Davy, 56

  Steel-mill, The, 193

  Stephenson, George, his attempts to make a safe lamp, 205


  Tanning, Lectures on, 72

  Telluretted hydrogen, Discovery of, by Davy, 131

  Tepidarians, The, 75, 78

  Ticknor’s account of Davy, 190;
    of Lady Davy, 190

  Tonkin, John, Davy’s benefactor, 9, 13, 20, 25, 53

  Torpedo, Electricity of, 183, 231

  Trinity College, Dublin, confers honorary LL.D. on Davy, 158


  Vauquelin, Davy’s account of, 178

  Vesuvius, Davy’s investigations on, 185, 187, 212

  Volta, Davy’s account of, 186;
    Faraday’s account of, 188

  Voltaic electricity, Davy’s contributions to, 93, 99, 100, 113,
          114, 126, 131

  ---- pile, Discovery of, 90, 93


  Warington, Professor, his estimate of Davy as an agricultural
          chemist, 98

  Watt, Gregory, his character, 21, 52

  Wavellite, Davy’s analysis of, 94

  “West Country Collection,” 30;
    characteristics of Davy’s contributions to, 37

  Wollaston, William Hyde, character of, 214, 217;
    his death, 232

  Wordsworth meets Davy on Helvellyn, 110


  Young, Thomas, his connection with the Royal Institution, 72;
    his review of Davy’s “Elements of Chemical Philosophy,” 167;
    death of, 234


PRINTED BY CASSELL & COMPANY, LIMITED, LA BELLE SAUVAGE, LONDON, E.C.




Transcriber’s Notes


Punctuation, hyphenation, and spelling were made consistent when a
predominant preference was found in this book; otherwise they were not
changed.

Simple typographical errors were corrected; occasional unbalanced
quotation marks retained.

Ambiguous hyphens at the ends of lines were retained.

Index not checked for proper alphabetization or correct page references.