Transcriber’s Notes:

Text enclosed by underscores is in italics (_italics_).

The whole number part of a mixed fraction is separated from the
fractional part with -, for example, 2-1/2.

Additional Transcriber’s Notes are at the end.

       *       *       *       *       *

SØREN HJORTH




SØREN HJORTH


  INVENTOR OF THE
  DYNAMO-ELECTRIC PRINCIPLE

  BY

  SIGURD SMITH
  C. E., M. I. F.

  PUBLISHED BY »ELEKTROTEKNISK FORENING« AT THE
  EXPENSE OF THE CARLSBERG FOUNDATION

  KØBENHAVN
  PRINTED BY J. JORGENSEN & CO. (M. A. HANNOVER)
  1912

       *       *       *       *       *

This pamphlet is published simultaneously in English and in Danish, and
is distributed among interested institutions all over the world.

Translated by F. SODEMANN, C. E., M. I. F.

       *       *       *       *       *

[Illustration]

  _Handsworth, Birmingham,
  Feb. 6th, 1851._

... After this wonderful force has been discovered by Your Excellency,
it has been my pride and interest that also the utilization thereof
should be originated by a Dane....

  (_Fragment of a letter from Hjorth
  to H. C. Ørsted._)




PREFACE.


Since the Life and Works of Søren Hjorth, the Dane was published in
the Danish technical journal the »Elektroteknikeren«, in 1907, a
statement concerning Hjorth’s rights of priority to the invention
of the dynamo-electric principle has been sent to the leading
foreign technical periodicals, viz. »Elektrotechnische Zeitschrift«,
»L’éclairage électrique«, and »Electrical Engineering«. As this
statement still stands uncontradicted, it seems reasonable to
consider Hjorth’s priority rights to this principle to be generally
acknowledged, even in the great centres of civilization. Therefore
I highly appreciated the courtesy of Mr. Hjorth’s heirs, after the
death of his step-daughter, Miss D. Ancker, in the autumn of 1908, in
offering me an opportunity to peruse the large collection of letters,
rough-copies, drawings, and sketch-books left by Hjorth, which threw
new light on his interesting life and work. Where it was previously
necessary to resort to guesswork alone, we are now able to base our
statements on established facts and to follow Hjorth’s train of ideas
almost from his first, to his last invention, and to see where he has
right and where he failed.

In the following pages, an account will be given of the results of
these recent researches in connection with what was previously known
about Hjorth.

  Charlottenlund 1911.

  _Sigurd Smith._




CONTENTS.


                      Page

  Preface.

  Søren Hjorth:

    Childhood and Youth  1

    The Railway          4

    Electricity          7

    Hard Times          18

  Sources               29

       *       *       *       *       *

SØREN HJORTH.




Childhood and Youth.


Søren Hjorth was born on the 13th of October, 1801. He spent his
childhood at Vesterbygaard, an estate rented by his father, Jens
Hjorth, in Jordløse Parish, north of Tissø. His mother’s maiden name
was Margrethe Lassen. Of their numerous children only two, besides
Søren, survived childhood.

The parents became early aware that their son possessed great
mechanical genius. He received his first education from the parish
school-master. After Hjorth was confirmed, his father leased the
beautiful estate Dragsholm, in Odsherred County, where he remained for
many years, and after the death of his first wife, he married baroness
Zytphen-Adeler.

Though he did not have an opportunity of learning much in his
childhood, Hjorth succeeded in his youth in passing an examination
which admitted him to the Bar. Later on he became the steward of
Bonderup Estate, near Korsør, but in this position he did not feel
satisfied, and in 1828 he became a volunteer in the State Treasury,
in Copenhagen. In 1836, he advanced to the position of Clerk of the
Exchequer and secretary. Although Hjorth’s occupation, during the last
30 years of his life, was mainly that of a civil engineer, he always
continued to be addressed as Secretary Hjorth, and by this title he is
still remembered by some of his surviving contemporaries.

Hjorth’s interests while at the Treasury were not concentrated solely
on his work there. Mechanical problems always fascinated him. It is
told that, during this period, he made all kinds of experiments at
Dragsholm, and, among other things, he constructed a thrashing-machine.
In 1832 he constructed a rotary steam-engine, which was made by
Schiødt, a mechanic residing at St. Annae Plads, and, upon Hjorth’s
application, it was bought by the King for 500 rixdollars in notes.
The King donated it to the newly founded Polytechnic Institute, this
being the place where it might best be utilized and »where this
original domestic invention might most suitably be placed«. The same
year, Hjorth described in »Ursin’s Magazines for Artists and Artisans«
a steam-car, invented by him and adapted to be propelled by means of
the rotary steam-engine. So Hjorth once more made a petition to the
Government for a subvention of 2000 to 2500 rixdollars to assist in the
practical manufacture of this car. The decision on this application
was postponed, however, at the suggestion of Professors Ørsted, Zeiss
and Forchhammer, because Hjorth had not yet finished the installation
of the boiler for the first steam-engine at the Polytechnic Institute.
Hjorth did not succeed in making the engine work, as it was not made
with sufficient accuracy. The sum for which the car was to be made, was
never granted, as petitioned for, although Hjorth had given up using
his rotary engine for it; and the car itself was probably never built.

At that time, the use of steam-cars on the country roads attracted
great attention in England, and many different constructions appeared.
In 1834 Hjorth, aided by subventions from the »Rejersen Foundation« and
the Government, went to England, in order to acquaint himself with the
use of these steam-cars on high-roads and railroads. During these years
he very actively investigated the use of steam-power, especially as a
means of propulsion for vehicles and ships. With admirable interest
and diligence he studied the steam propelled road-carriage, and for
a long time he considered that to be the future means of conveyance.
Although he did not succeed in getting his own steam-carriage put to
practical use, he made many experiments on a steam car, and I am told
by one of his passengers that on the level streets of Copenhagen and
Frederiksberg all went very well, but the carriage could not climb
Valby hill.

During these years, Hjorth also attended the lectures at the
Polytechnic Institute, and he was especially interested in Ørsted’s
lectures on the physics of the globe, and on electricity and magnetism.

Notwithstanding his unsuccessful experiments with the rotary
steam-engine, Professors Ørsted, Zeiss and Forchhammer had to give
him a warm recommendation, when he made a petition to the Ministry in
order to get his expenses refunded by the Government. They mentioned
his indefatigable zeal, his great diligence, and the considerable
expense borne by him in the pursuit of his researches. The numerous and
expensive experiments absorbed all the money Hjorth could procure: not
only his salary was spent, but also such funds as he was able to raise
among his friends.




The Railway.


In 1839 Hjorth made a journey to England, France and Belgium. By that
time, he seems to have come to the conclusion that steam-carriages
running on rails, are preferable to steam-carriages running on the
high-road, at any rate he mainly studied locomotives and railroading
during this journey.

After his return to Denmark, he spent some years as manager of
Marschall’s piano factory, though still at work with his railroad
schemes, and in 1840 he happened to find a man named Schram, a
book-keeper, who shared his interests and was able to assist him in the
realisation of his ideas. In 1840, these two men published a detailed
calculation of the probable revenues and expenses of a railroad between
Copenhagen and Roskilde. This project, however, did not arouse any
interest, and people were mostly inclined to smile at the idea, and it
appeared impossible to induce competent men to take, any interest in the
scheme, much less to invest money therein.

Then, in 1841, they applied to the young »Industrial Association« which
body referred the case to its special committee of commerce. Even this
committee did not seem much inclined to listen to Hjorth’s and Schram’s
proposition, but their undefatigable energy finally succeeded in
persuading the committee of commerce to convoke a large meeting to be
held on the 24th of March. Here it was decided to make an application
to the Government for the surveying of the proposed railroad line and,
to the surprise of many, the petition was granted. Hjorth, possessing
distinctive agitatory faculties, showed great activity, delivering
lectures and exhibiting models, and tried thereby to excite interest
in his schemes. His contemporaries describe him as a sociable man of
a winning and lovable disposition and possessing a certain persuasive
power. He was well liked by his friends as well as by his many casual
acquaintances. In 1841 both Hjorth and Schram were elected members
of the Board of Representatives of the Industrial Association, and
from 1841 to 1843 Hjorth was the vice-president of the association.
Now there began to be some sympathy for their cause, and the Board of
Representatives of the Industrial Association showed a willingness to
follow the sub-committee elected, consisting of the two motionists and
Lector, (later Professor) Wilkens of the Polytechnic Institute. The
strenuous efforts of this sub-committee resulted in the Industrial
Association submitting, in January 1843, an application for a franchise
to form a stock-company for the purpose of building a railroad from
Copenhagen, by way of Roskilde, to a sea-port on the western coast of
Sealand. This franchise, was granted, for a period of 100 years, and
on the 16th of April 1844 the Industrial Association issued a public
invitation to take stock in a company whose stock capital was to be
1-1/2 million rixdollars, a very considerable sum for those times. As
early as in the beginning of May, most of the stock was taken--mainly
in Hamburg. While the confidence in a scheme of this kind was but
slight in Denmark, the speculation in railroad stocks was nearly
culminating at the stock-exchanges of Germany and England; as a matter
of fact, it became near being a swindle. The Sealand Railroad Company
was founded on the 2nd of July 1844, and Hjorth became its first
technical director, while Schram became its first general manager. The
Industrial Association received 15000 rixdollars for the franchise,
and from this sum it paid 3000 to Hjorth and Schram.

In 1843, Hjorth was unanimously elected president of the Industrial
Association. In 1845, he had to resign this office, but as it appeared
very difficult to concentrate the votes in favour of a new president
and vice-president, »Secretary Hjorth, to meet the general demand,
accepted the vice-presidency«, which office he then held for a year.

In the meantime, the railroad company had finished the construction
of its first piece of road, from Copenhagen to Roskilde, and this was
opened for traffic on the 27th of June 1847, some days before the
time limit fixed. Even at that time it was decided, owing to Hjorth’s
influence, to extend the road to Korsør. The cause of the delay in
commencing this work was the railroad crisis which had just broken out
in Germany and England, making it impossible to obtain money for the
construction of railroads. This road, therefore, was not constructed
until the government, in 1852, guaranteed an interest of 4% on the
capital invested.

Hjorth retained his position for about 4 years, and concerning this
period he writes: »All the great difficulties and obstacles to be
surmounted during the construction of the road influenced my health to
such a degree that I broke down and was forced to abandon my position
as technical director of the railroad before the expiration of my term
of office, in order that I might take a water-cure at Klampenborg«.
After he had, to some extent, regained his health there, and another
board of directors had been elected, he made a travel to England which
turned out to be of such great importance that we will describe it more
fully in the following.




Electricity.


After Faraday, in 1831, had discovered how an electric current might be
produced by means of a magnet, many people busied themselves by trying
to put this invention into practical use, and numerous attempts were
made to construct electro-magnetic and magneto-electric machines for
useful purposes.

No wonder that these efforts attracted Hjorth’s attention, and, as
early as 1842, he had drafted an electro-magnetic machine, consisting
of a stationary circle of magnets, whose poles were directed against
the poles of a moveable circle of magnets. In 1843 this sketch was
deposited with the Royal Scientific Society, but the sketch itself, as
well as the explanation belonging to it, are very incomplete.

In the month of April, 1848, Hjorth made a petition to the government
for a subvention of 200 rixdollars, in order that he might go to
England to get an electro-magnetic machine[1] designed by him, made
there. Hjorth had noticed that, in a piece of iron encircled by
an electric current, the magnetism only to a certain extent would
increase, with the strength of current, there being a point of
saturation for the iron. When this point has been reached, it will be
of no use to increase the intensity of the current, since the magnetism
will not increase any further. On the basis of this observation, Hjorth
had constructed his machine, but he had confided the details thereof
only to Professors Ørsted and Forchhammer. In the report on Hjorth’s
petition made by these two professors to the Board of Trade, they,
curiously enough, take exception to the above-mentioned observation
by Hjorth, while its correctness will now be acknowledged by any
electrician. These professors, however, advised that Hjorth’s petition
should be granted, using this liberal argument, worded by Ørsted:
»Regarding the petitioner’s new electro-magnetic machine, we must state
that we find it quite ingenious, and although we are not convinced
that it will produce remarkable effects, we should consider it useful
to have a working model executed. Having during so many years worked
for this case, the petitioner might perhaps, by the execution of such
a model, be enabled to make some further invention, which would bring
him nearer to the goal. Indefatigable zeal has often accomplished its
purpose, where science had to declare the means at first used, to be
entirely inadequate, but where, by continued work, entirely different
means, previously unknown to the inventor, were found. Inasmuch as the
sum of 200 rixdollars asked for is so small, we find it advisable to
grant the subvention. Still we cannot refrain from remarking that the
petitioner’s machine may just as well be made here as at any other
place«.

Thus the discoverer of electro-magnetism cleared the road which was
to lead to the most beautiful application of electro-magnetism, that
application which, before all others, has been of radically reforming
importance during the last half century, thereby throwing double
splendor on Ørsted’s name.

Soon after his arrival at London, in the summer of 1848, through a
firm which he knew from an earlier period of his life, Hjorth made
the acquaintance of a nephew of Bramah, the renowned mechanician and
inventor of the Bramah-lock. Hjorth’s invention was then laid before a
friend of Bramah’s, a civil engineer named Gregory, who had made the
study of magnetism his specialty. Gregory at once persuaded Bramah
to bear the expense of making a machine, and of securing patents in
England and several other countries, on condition that the expected
profits should be divided between him and Hjorth. Later on, B. Taylor
and Normann Innis were taken in as partners, paying together £1000, and
then Charles Stovin (£600) and Robert Broad, of the Henley Iron Works
(£500). Two machines were now made, according to Hjorth’s directions,
by the firm of Robinson & Sons, Pimlico, London. One of these is
shown in Fig. 1, and is apparently quite an ingenious imitation
of the steam-engines of those days. _C_ is a movable, _A_ a fixed
electro-magnet. Their peculiar shape, involving several conical pins
fitting into corresponding cavities, was thought to be advantageous for
the distribution of the effect of the magnetic force over a longer
stroke. The »piston« _C_, reciprocating up and down, drives a crank
shaft having two opposite cranks. To either of the cranks there is a
corresponding group of magnets. An eccentric fixed on the shaft, moves
a »slide valve«, alternately closing the circuit of one or the other
of the two groups of magnets. When the one piston is at its lowest
position, the circuit of the other group of magnets is closed, and
its piston is attracted, until it reaches its bottom position; then
the current is shifted, and the other piston attracted, etc. In order
to avoid the formation of sparks at the circuit breaker, an ingenious
device was provided, closing the current of one group of magnets,
immediately before that of the other one was broken. The first machine
was made with a 4 inch stroke, the next one with 13-1/2 inch stroke.
The magnetic attraction per square inch of the piston, had about the
same magnitude as the pressure per square inch in the low pressure
steam-engines of those days. The patent application was filed in London
as early as in October 1848, and it was granted on the 26th of April
1849[2]. On the 21st of September, the same year, Hjorth obtained
a fifteen year monopoly in the kingdom of Denmark, to manufacture
machines, utilizing electro-magnetism as motive power in the above
described manner.

[Illustration: Fig. 1. Hjorth’s Electromotor.]

The larger of the machines here referred to was shown in action
to several technical experts, and created considerable sensation,
especially on account of the great length of stroke attained--13-1/2
inches--and the uniform motion of the machine. The machine is mentioned
in »Mining Journal«, for the 5th of May, and 16th of June 1849, and an
extract of these articles is published in the »Flyveposten« for the 3rd
of July the same year.

Hjorth was invited to show the machine at the Royal Society, and at
the annual meeting of the Society of Civil Engineers, of which he was
a member. It was exhibited at the Universal Exhibition in London, in
1851. In the catalogue it was highly commended, and it received the
only prize-medal awarded to electrical machines.

There was, however, one essential obstacle to the practical use of this
machine, namely the lack of means for cheaply producing electricity
in the quantities required by the electromotor. Wet batteries were
expensive to use, and if the machine were to become useful in practice,
a powerful »dry battery« would be a necessity. Most of the then known
machines producing electricity, were fitted with permanent steel
magnets, and as the point of magnetic saturation of steel is low,
these machines were unable to produce any considerable quantities
of electric energy. Hjorth therefore imposed upon himself the task
of building a dry battery. His sketch-book from 1851 is full of new
schemes for such batteries and improvements on those already existing
(Woolrich’s, Elkington’s and Paine’s). From this it appears, among
other things, that he was fully aware that, when the spools suddenly
entered or left the field, difficulties would arise in the commutation,
and he therefore improved the machine by bending the field magnets,
obtaining thereby a gradually increasing and decreasing field, the
same thing which is, nowadays, attained by using pointed or obliquely
cut pole-shoes.--It would be very tempting to study more closely these
sketch-books with their neatly colored drawings, showing how many
different ideas have been fostered by him, before the actual production
of the first dynamo, in 1854. Most of the descriptions and notes have
been written in the English language, which he used almost as readily
as his native tongue. On the 1st of May, 1851, Hjorth writes in his
sketch-book, beside a sketch of a machine having copper discs for
armature conductors and cast iron electro-magnets: »_By passing the
current on the said way round the Electromagnets, these will of course
be excited in proportion to the strength of the same, and the more they
are excited, the more will the discs be influenced by the magnets, a
mutual action thus taking place_«.

So it appears that Hjorth, as early as on the 1st of May 1851, with
perfect clearness, has pronounced the dynamo-electric principle.

Under the date of June 24th, 1851, we find sketched out another
beautiful idea for the construction of a dynamo. It must be regretted
that this machine has not been executed, as it would certainly have
proved superior to his dynamo of 1855, which has many points in common
with this project. Fig. 2 shows a reproduction of this page of the
sketch-book. There is no descriptive text to this sketch, only at
one side of the drawing, these very significant words are written:
»Magneto-Electric arrangement with mutual action«. All the six
powerful held magnets are of cast iron, and they are wound so as to be
magnetized by the current, produced by the dynamo itself[3].

[Illustration: Fig 2. Facsimile of a Page of Hjorth’s Sketch Book, June
24th 1851.]

In November, 1851, Hjorth returned to Copenhagen, and here he continued
what he had commenced in England. In May, 1852, he deposited with the
»Society of Sciences« some papers, signed by Professors Scharling and
Forchhammer in December, 1851. These papers contain two descriptions,
written in English, and two drawings of »dry batteries«. These consist
of 3 or 4 circular rows of vertical steel rod magnets, placed one
above the other, and disposed round a vertical shaft, carrying 2 or 3
circular rows of armatures. Each armature consists of a piece of soft
iron, and is wound with a strip of copper, in a special manner. There
are, in each row, as many armatures as magnets. The hollow shaft, as
well as the magnets, which are fitted with shoes of soft iron, are
wound, and encircled by the current produced in the armatures. With
regard to the magnetic arrangement, this machine comes very near to the
one patented by Brett in 1848, and it will be noticed that it cannot
be said to be constructed according to the dynamo principle, as the
»mutual« action plays no important part, the magnets being permanent
steel magnets, hardly adapted to receive much extra magnetism by the
current of the machine. Hjorth points out, as the novel feature of
these machines, the division of the steel magnets into many small ones,
with an armature corresponding to each magnet. Hereby he claims, for
the same weight of the steel magnets, a larger capacity of the machine
than if he had used fewer, but larger steel magnets[4]. The machine
is fitted with a commutator for direct current.--In March, 1854, the
sketch-book contains another sketch of a dynamo, with clear indication
of the dynamo principle, approximately as it was patented on the 14th
of October the same year[5]. This sketch is reproduced in Fig. 3. The
machine has two permanent cast iron magnets and two electro-magnets.
The armature cores are fitted with oblique pole-shoes. The description
is very brief and contains the same as the patent specification.

[Illustration: Fig. 3. Facsimile of a Page of Hjorth’s Sketch Book,
March 1854.]

In 1853 Hjorth negotiated with a certain Dr. Watson, who had
constructed a »dry battery« by means of which Hjorth had meant to drive
his electro-magnetic machine. The object of their negotiations was
to buy out Hjorth’s above-named partners, and to form a new company
for the purpose of exploiting the above-mentioned two machines. The
partnership, however, was not realized, and in spring of 1854, Hjorth
himself commenced to have a 3 HP battery built in Copenhagen. The
machine was fitted with cast iron magnets, and in all probability it
was similar to the project of March 1854, and agreed with the patent of
October, the same year.

This patent specification reads as follows: »The main feature of this
battery consists in applying one, two, or several permanent magnets
_A_, of cast iron, and shaped as shewn in the drawing (Figs. 4 and 5),
in connection with an equal number or more electro-magnets _B_, shaped
as indicated in drawing, in such a manner _that the currents induced
in the coils of the revolving armatures are allowed to pass round the
electro-magnets; consequently, the more the electro-magnets are excited
in the said manner, the more will the armatures C be excited, and
the more electricity of course induced in the respective coilings_;
and while a mutual and accelerating force is produced in this manner
between the electro-magnets and the armatures, an additional or
secondary current is at the same time induced in the coiling of the
electro-magnets by the motion of the armatures, the said current
flowing in the same direction as that of the primary current, after
having passed the commutator. The direction of the current induced
in the coils of the armatures will, of course, be reversed according
to the change of the respective polarities, and the commutator _D_
is therefore applied for the purpose of causing the current to flow
constantly in one direction«. Then follows a description of the
commutator of the dynamo. Finally the pole-shoes, or false poles,
provided on the magnets as well as on the armatures, are mentioned. He
points out that the false poles have on the side of attraction, a long
straight edge, as distant from the centre as possible, while on the
side of separation, either one has a sharp point, nearer to the axis
of revolution, »all with a view to avoid reactionary currents, and at
the same time to facilitate the motion of the armature«. »While steel
magnets also may be applied instead of cast-iron magnets, the permanent
magnets may be coiled like the electro-magnets, which also will serve
to make them more permanent«.

[Illustration: Fig. 4. Hjorth’s Dynamo 1854.]

[Illustration: Fig. 5. Hjorth’s Dynamo 1854. Fragment of the Patent
Drawing.]

From the above-named sketch-book notations, and the patent
specification, it will be seen that Hjorth, during the years 1851-54,
has repeatedly pronounced the dynamo principle with perfect clearness,
and that he has utilized it in several projects.

It is worth noting that Hjorth’s so-called »permanent« magnets
are of cast iron. This shows that Hjorth has known of remanence,
or permanence. He has known that cast iron always possesses some
slight magnetism, either induced by the earth magnetism or as a
remnant--remnant magnetism--left over from its being magnetized in a
coil. It has heretofore been assumed that Siemens was the first to call
attention to this property of iron, in his paper in the transactions
of the Royal Society, of the 14th of February, 1867.--Thus Hjorth
used this weak remanent magnetism in the large cast iron magnets
to produce the initial current in the dynamo, which then excites
itself.--At the end of the patent specification, Hjorth points out that
the remanent magnets may also be coiled (compare Fig. 2), and thereby
he comes closer to the later dynamo constructions.

Hjorth is quite right, according to the patent specification, in
giving the pole-shoes such a shape that the armature is gradually
demagnetized, and in stating that the object of this is thereby to
avoid reactionary currents, and consequently the formation of sparks;
while he is mistaken in believing to be able to facilitate the motion
of the armature by giving the pole-shoes a certain special shape,
because in that case, the machine would be a _perpetuum mobile_.

Together with the above-mentioned dynamo, Hjorth had an electromotor
made in Copenhagen, essentially similar to the one exhibited in 1851.
When in the autumn 1854 the machines were finished, Hjorth was called
back to England, in order to continue the work on his inventions.
It is not known whether the machines were sent to England or not;
at any rate they aroused some interest there, and he had a new and
larger dynamo built by Messrs Malcolm & Campbell; of Liverpool, 7
India Buildings, at the expense of Malcolm and others. This machine
was patented in 1855[6], and is shown in Fig. 6, which is reproduced
from a photograph. Here, too, the dynamo principle has been followed,
but each electro-magnet is composed of one solid and one tubular
electro-magnet, the latter enclosing the former, the two together
forming a so-called »_cup magnet_«, a construction which has also been
used by later inventors. Hjorth describes the action of the battery as
follows: »_The permanent magnets acting on the armatures, brought in
succession between their poles, induce a current in the coils of the
armatures, which current, after having been caused by the commutator
to flow in one direction, passes round the electro-magnets, charging
the same and acting on the armatures. By the mutual action between the
electro-magnets and the armatures, an accelerating force is obtained,
which in the result produces electricity greater in quantity and
intensity than has heretofore been obtained by any similar means._« At
the same time, Hjorth allowed the dynamo patent of 1854 to lapse, it
being merely a provisional patent.

[Illustration: Fig. 6. Hjorth’s Dynamo 1855, from an old Photograph.]

Together with the dynamo patent of 1854, Hjorth secured a provisional
patent on an improved electromotor[7], and together with the dynamo
patent of 1855, he obtained the complete patent on the above mentioned
electromotor, as well as on another construction thereof[8]. The former
consisted of hollow, horizontal electro-magnets (cylinders), being of
a special shape inside, adapting them to give to an electro-magnetic
piston, reciprocating within them, a long and steady stroke. By means
of a crank, the stroke was transformed into a rotary motion. The
other electro-motor consisted of wheels, with protruding teeth, which
were set in rotary motion by the teeth being attracted into hollow
electro-magnets.

FOOTNOTES:

[1] According to the usual terminology of those times, an
»electro-magnetic« machine means a machine driven by electricity, an
electromotor, while, on the other hand, a »magneto electric battery«,
or a »dry battery« is a machine for producing electricity.

[2] Specification of Patent No. 12295, 1848.

[3] After the publication of my first treatise in the
»Elektroteknikeren«, for February 1907, various parties have objected
that Hjorth, in his dynamos, did not use the dynamo principle in
its purest form, as he had one large, unwound, cast iron magnet.
On the contrary, the above-mentioned leaf of his sketch-book shows
that Hjorth, as early as in 1851, has used the dynamo principle in
its purest from--exactly the same as used by Siemens in 1867--as all
the field magnets have been wound cast iron magnets, and the initial
current is induced by the remnant magnetism of these magnets. _S. S._

[4] This is correct, as long as he uses armatures with but a single
winding, because, in that case, the number of armature windings
is proportional to the number of steel magnets. Whereas Hjorth is
mistaken, when in 1867 he makes the same statement about a machine,
where nothing prevents the armature from being fitted with a great
number of windings.

[5] Specification of Patent No. 2198, 1854.

[6] Specification of Patent No. 806, 1855.

[7] Specification of Patent No. 2199, 1854.

[8] Specifications of Patents No. 807 and 808, 1855.




Hard Times.


In May, 1856, Hjorth returned from England, disappointed. It will be
noted that through the electro-motor Hjorth was led to occupy himself
with the dynamo machine. The dynamo was built in order to produce
motive power for the motor. All the time he was working on these two
inventions, it was his firm belief that if he could make the dynamo
drive the electro-motor, he would be able to attain a substantial
saving in power, get much more power out of the electro-motor than was
consumed in driving the dynamo. The machines would, as it were, run
automatically. He could not understand, why Dr. Watson was sceptical
with regard to this manner of battery action. He intended to install
his machines in ships and locomotives, which would then be propelled
with a minimum consumption of power. In short, the combination of
dynamo and electro-motor imagined by Hjorth was to be a _perpetuum
mobile_. It has certainly been the great disappointment of his journey
to England, that this scheme failed.

On reading about this mistake, one is inclined to base the judgment
of Hjorth upon assumptions belonging to the present time. But this
would be a great injustice to him. The axiom that the quantity of
energy in nature is unalterable, and consequently a _perpetuum mobile_
an impossibility, has, as it were, been imbued by our own generation
with the mother’s milk. Not so with Hjorth. Not until the forties of
the last century, did Mayer, Joule and Colding, the City Engineer of
Copenhagen, set forth their theories about the permanency of energy,
and about the convertibility of heat into mechanical activity, and
of the latter into heat again. These theories, however, were very
slowly accepted, even by scientists. It is, therefore, no wonder that
a man like Hjorth, having no special scientific training, could not
easily digest the new theory and Hjorth did not have any instinctive
sensation of having entered upon a hopeless and impossible track. On
the contrary, he imagined the new wonderful form of energy to conceal
unestimable possibilities which he had only to wrest from nature.

Though Hjorth was thus ship-wrecked on his favourite idea, he
nevertheless discovered new land, fertile for coming generations. His
intrepid zeal guided him, as Ørsted had anticipated, in spite of his
lack of scientific education, on to the road leading to the splendid
results of this day.

None of Hjorth’s original partners participated in the manufacture of
his latest machines, and possibly this was due to his above-mentioned
erroneous idea. Only one of his English friends, Wm. Macredie, of
Melbourne, maintained his attachment to Hjorth and his confidence in
him to the last. He was always very interested in Hjorth’s schemes,
and, besides, he shared his religious creed.

Hjorth was very anxious as to his future. When he returned from
England, he stood quite destitute and felt depressed by poverty. His
health was not of the best, and his formerly so neat hand-writing had
become unsteady. He received, shortly after his return, a communication
from his English partners that they wished to have the dynamo patented
in Denmark and France, which showed that they had faith in this
machine, but nevertheless these were hard times for Hjorth.

The dynamo remained for some time with Malcolm, in Liverpool, and
negotiations for its sale were several times entered into, but were
without results. It was tested on several occasions, but these tests
proved that it could not yield as much as might be expected from
its size. The uncoiled magnets, which were originally of cast iron,
were replaced by more powerful steel magnets. Upon the whole, this
dynamo had a rather eventful existence, for first every other magnet
pole was removed (see Fig. 6), and then it was proposed to rewind the
magnets. In May, 1857, it was donated to the Polytechnic Institute,
Regent Street, in London. Among the papers left by Hjorth, there are
a daguerreotype and a photograph of this machine, (from which the
accompanying Fig. 6 is reproduced).

Notwithstanding a thorough search of the London museums, it has been
impossible to trace this machine, which is said to have been seen in
London during the nineties.

Hjorth was now compelled to find a new means of earning his livelihood,
and to make new connections. In 1857, he became the representative of
Cyclop’s Steel Manufactory, Charles Cammell, of Sheffield, and in 1859,
he applied for and obtained a licence as a translator of English in
Copenhagen. Finally he had a kind of engineering and patent office,
assisting strangers in obtaining monopolies, and doing work for new
railroads, bridges etc. In the beginning of the sixties he caused a
research to be made concerning the use of coals from Hornholm and
Silkeborg, and the use of peat for briquettes. In April, 1860, he
applied to the government for a position, enabling him to work for the
building of new railroads in Denmark, and at the same time he referred
to his previous merits in that direction. As he had not, within a year
thereafter, received any position, he made a petition for a yearly
pension, in case such a position could not be given to him. As »the
idea of building the Sealand railroad, as well as the general location
of this road, is mainly due to Secretary Hjorth ... and further more,
no small share in the completion of the undertaking is due to him«, it
was proposed, on the budget for 1861-62, to grant a pension to Hjorth.
That year and the following ones, until his death, he received 500
rixdollars.

During these years, Hjorth lived at 10 Nørrebrogade. In 1845, he
married Vilhelmine Ancker, née Hansen (born on the 27th of March,
1805), the widow of the farmer Diderick Ancker, of »Lille Egede«, and
thereby he became the step-father of two daughters. This marriage was
childless.

This carefully dressed little man[9] in top-hat and high-heeled shoes,
was well known, and very well liked in many circles. He was always
amiable and willing to help, and it is known that he has, at great
personal sacrifice, assisted young artisans who were in hard luck. In
society he attracted attention by his power of fascination and by his
universal knowledge. On Sundays he was regularly seen directing his
steps to St. John’s church, where, for many years, he was a member of
Rev. Frimodt’s congregation.

During the period of depression above described, Hjorth could naturally
not very well afford to occupy himself with experiments, nor had he
much time. Still, in 1857, he secured permission to undertake, at the
navy yard, some experiments concerning the carrying capacity of a
magnet at varying distances between the pole and the armature, and at
the same time he sketched out the construction of an electro-motor,
especially well adapted to utilize the magnetic attraction. This
electro-motor was built in Copenhagen with funds granted by the
»Classenske Fideicommis«. When it was finished, Hjorth applied for the
money needed to make it double acting.

In autumn 1860, Hjorth was in Paris, and there he worked for his
electrical inventions.

In 1866, Wilde published his machine, in which the current needed to
magnetize the electro-magnets was produced by a permanent magnet.
This is exactly the principle, underlying the dynamos built by Hjorth
in 1854 and 1855. Hjorth’s good friend, Wm. Macredie, Melbourne,
sent Hjorth a clipping from an English periodical mentioning Wilde’s
machine, and called his attention to the identity.

It is to be regretted that Hjorth’s answer is not known, as his
copy-book for 1866 has been lost.

Considering the data at hand when Hjorth’s biography was published
in 1907, one might be inclined to believe that Hjorth had invented
the dynamo principle and then dropped it at once, going back to steel
magnets. It is, however, clearly evidenced, by the papers left by
Hjorth, that this has not been the case, but that Hjorth has used the
dynamo principle, in various, more or less pure, forms, in practically
all his projects from 1851 to 1870.

[Illustration: Fig. 7. Sketch of Hjorth’s Magneto-Electric Machine
1867.]

As previously mentioned, Hjorth had been disappointed in his attempts
to produce energy through an electrical transmission of power, but
this did not cause him to relinquish the idea of producing energy by
electric means. He took this up again in a new form in his old age. In
order to have this idea carried out in practice, Hjorth had a machine
built, a description and drawing of which is to be found in a pamphlet
published later on in French and Danish. From this it appears that the
machine was not originally built according to the dynamo principle.
Hjorth found no advantage in using the expensive electro-magnets, as
it was his main object to prove that, by his special arrangement of
armatures and magnets, he could reduce the power required to produce
a certain amount of electrical energy. The machine, in its manner
of construction, reminds one to some extent, of Hjorth’s project of
1851. Two or three rings, or wheels, of armature coils _A_ (see Fig.
7) revolve between three or four circular rows of magnets _M_. This
decreased consumption of power was to be attained by offsetting the
armature wheels somewhat relatively to one another, for instance so
that when one armature of the topmost wheel was opposite one magnet
pole, an armature of the next armature wheel would be spaced one
quarter of a pole distance from a pole, and an armature of the lowest
wheel would be one half pole distance from a pole. As it is well known,
this idea is entirely erroneous, it being contrary to the axiom of the
constancy of energy.

The machine was built into a casing, and was sent to the Paris
exhibition of 1867. Hjorth was always very careful not to give any
information about his inventions to anybody. At the end of April, he
went to Paris himself. The machine had suffered some injury on the
journey, and had to be repaired in Paris, and therefore it made its
appearance rather late. Still he succeeded in having it submitted to
the judgment of the jury, and a test of electrolytic deposition was
made, which proved entirely successful.

In Paris he met a certain business-man who, later on, requested to
enter into partnership with Hjorth. This man was an adventurer, whose
ambition was to become a Knight of Danebrog. It is only to be regretted
that this person obtained so great a power over Hjorth, and understood
how to deceive him. The previously mentioned pamphlet, edited by the
partner, and named »Batterie magnéto-électrique de Søren Hjorth«, is a
document of the poorest kind.

Through his partner, Hjorth was introduced to various electricians
and men of science, among others the renowned Samuel B. Morse, who
recommended Hjorth’s machine, but took exception to his idea concerning
the production of energy.

The electrician who repaired Hjorth’s machine, introduced him to the
president of the French Société d’Encouragement, who had proposed
a competition for electrical machines, and had offered a prize
of 3000 fr. for a machine, complying with the conditions given.
Hjorth’s machine was sent to the society, but he did not succeed in
obtaining the prize, which was awarded to the subsequently so famous
»Alliance« machine. On the 7th of July, Hjorth, probably prompted by
his partner, obtained an audience of Emperor Napoleon III. After he
had demonstrated his invention, and shown the letter from Professor
Morse, the Emperor asked him what he could do for him, and Hjorth
answered that his highest desire was to have a larger machine built,
and he requested the Emperor’s protection and assistance, in order to
accomplish this. The Emperor ordered an examination of the machine
to be made. The well-known Professor Jamin was retained as an expert,
and Hjorth demonstrated the machine before him. On the following day
it was examined, in the presence of Hjorth and his partner, by Jamin
and other men of science. They subsequently had the machine sent to
the exposition, where they measured the voltage and intensity of
current, and expressed their satisfaction, as to the results attained.
Nevertheless Hjorth was disappointed to receive, the next day, through
the representative of the Emperor, General Favé, a communication that
the subvention applied for could not be granted.

At the exposition, a great sensation was created by a dynamo exhibited
by Ladd. This machine had two electro-magnets and two armatures,
the current being directed from the smaller armature round the
electro-magnets and taken from the larger armature to the exterior
circuit, lights for instance. Thus the machine was evidently built
according to the dynamo principle.

In order to claim his right of priority to this principle, Hjorth went
to the prominent authority on physics, Count Th. du Moncel, who later
on became the editor of »La lumière électrique«. As Hjorth himself did
not know French, the interview probably took place through his partner.
About this, Moncel writes in the above mentioned periodical, in 1883,
that Hjorth’s representative was not very conversant with electrical
matters; therefore he was unable to express himself clearly, and
consequently Hjorth’s rights of priority were not acknowledged.

Having received the Emperor’s refusal, Hjorth went home, broken down by
illness and disappointments.

In 1868-69 Hjorth, due to the interest taken in his case by the
manufacturer Mr. Kähler, succeeded in having a small machine built in
this gentleman’s shop in Korsør. At the same time, a larger machine was
made in Copenhagen, the necessary funds being contributed by several
country gentlemen and merchants interested in the case. Finally, in
December, 1868, a body of prominent men addressed the government,
petitioning a subvention of 15,000 rixdollars to be given to Hjorth, in
order to enable him to build a new and larger machine. As the Ministry
was not inclined to grant a sum of this size, it proposed to grant
1000 rixdollars, in order to have the existing machines examined by
Professor Hummel and other experts. This proposition was accepted by
Hjorth, and a commission was formed, consisting of Professor Hummel,
assisted by Professor Holten, Instructor Lorenz and Winstrup, a
mechanic. As early as December, 1868, Professor Hummel, together with
head-master Ibsen from Sorø, had visited dyer Gülich of Christianshavn,
where one of the machines was located, and they made a few tests,
which Hummel himself did not consider to be of any importance. The
experiments were to be made in April, 1869, after an assistant had
made a preliminary experiment, but then Kähler reported that he had
taken the machine apart, in order to make an alteration therein, and
that this would take a couple of months. It appears, from a letter
from Hjorth to the Ministry of the Interior, that Hjorth had arrived
at the conclusion that he must resort to the use of electro-magnets,
to a certain extent, at least, on account of »the steel, by continued
use, losing part of its magnetic power, which necessitates its being
re-magnetized«, and partly because »it appears that electro-magnets
may be made to yield a considerably larger magnetic power than steel
magnets, by means of the electrical current induced thereby«. As this
change to the dynamo principle was estimated to cost 400 rixdollars,
Hjorth was informed, in April 1869, that this amount would be paid out
of the sum, granted for the experiments, when the smaller machine had
been re-built.

Hjorth’s answer to this was a petition that the 400 rixdollars might
be spent on any battery, which he might build. Hereafter the case died
out. His petition was not answered until in April 1870, and the answer
was a refusal.--At that time Hjorth was in delicate health, and his
energy had been broken, and a few month’s afterwards he died, on the
28th of August, 1870. He was survived by his wife, who died on the 30th
of September 1885.

This indefatigable worker did not succeed in seeing or reaping the
harvest of his work for the utilization of electricity,--perhaps his
aim had been too high. At a period when in all countries stone was
added to stone in the foundation now supporting electrical engineering,
we Danes have also made our contribution. Hjorth did not possess the
profound knowledge nor the sharper insight necessary in order to avoid
errors, but his perseverance, his industry, and his sacrifices, ought
to be acknowledged, and his name ought to be venerated on account of
his contributions to the development of electric machinery.

FOOTNOTE:

[9] Hjorth’s English passport, from 1855, contains this information:
Height: 5 feet 7 inches, Complexion: fresh, Eyes and Hair: grey.




SOURCES.


After Hjorth’s death, few knew that he had discovered the dynamo
principle. If Hjorth himself had understood the importance of this
discovery, and the magnitude of the revolutions to be caused thereby,
he would undoubtedly have endeavoured to propagate the knowledge
thereof. It was not until 1879, when Colonel Bolton read a paper before
the Society of Telegraph Engineers in London, that Hjorth’s patent No.
2198, of 1854, was again brought out of oblivion, and accompanied by
these words: »This appears to involve the principle which was later
on taken up by others«. Count du Moncel, who had received Hjorth’s
representative in 1867, when reading these words, was reminded of the
case. Thereafter he has given Hjorth a fair redress in the above-cited
article in the valuable periodical »La lumière électrique«, edited by
him, the heading being »The Actual Inventor of the Principle of the
Dynamo-Electric Machine«.

Among the few printed sources of information concerning Søren Hjorth
and his inventions, the following may also be mentioned:

  _C. Nyrop_: Industriforeningen i København, 1838-1888.
  _Du Moncel_: L’éclairage électrique, 1884, page 102.
  _Electrician_, July 8th, 1882.
  _La lumière électrique_, 1883, VIII, page 58.

The most important source is the papers, left by Hjorth, which comprise
a considerable collection of drawings, letters, and rough copies of
letters written by him. These documents furnish full information,
not only of Hjorth’s inventions, but also of his entire reasoning
and manner of being. Probably the most interesting of all are his
note-books and sketch-books, wherein he used to note down his ideas in
English, and which are accompanied by neatly made, coloured sketches.
These papers were not accessible to the public until the autumn of
1908, and they are now preserved in the archives and library of the
Polytechnic Institute in Copenhagen.

Important contributions to Hjorth’s history have also been obtained
from the State Archives, the Archives of the Society of Science, the
Archives of the Polytechnic Institute and from the papers left by H. C.
Ørsted.

       *       *       *       *       *

Transcriber’s Notes:

Footnotes have been moved to the end of each chapter and relabeled
consecutively through the document.

Illustrations have been moved to paragraph breaks near where they are
mentioned.

Punctuation has been made consistent.

Variations in spelling and hyphenation were retained as they appear in
the original publication, except that obvious typographical errors have
been corrected.