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BRITISH MANUFACTURING INDUSTRIES.


EDITED BY
G. PHILLIPS BEVAN, F.G.S.


POTTERY,
BY L. ARNOUX, Art Director and Superintendent of Minton's Factory.

GLASS AND SILICATES,
BY PROFESSOR BARFF, M.A.

FURNITURE AND WOODWORK,
BY J. H. POLLEN, M.A., South Kensington Museum.


_SECOND EDITION._

LONDON:
EDWARD STANFORD, 55, CHARING CROSS.
1877.




Transcriber's Note: Printer's inconsistencies in spelling, punctuation
and hyphenation have been retained. In the text Mn.O_2, the
underline (_) is used to indicate that the 2 is printed as subscript.




PREFACE.


The object of this series is to bring into one focus the leading
features and present position of the most important industries of the
kingdom, so as to enable the general reader to comprehend the enormous
development that has taken place within the last twenty or thirty
years. It is evident that the great increase in education throughout
the country has tended largely to foster a simultaneous interest in
technical knowledge, as evinced by the spread of Art and Science
Schools, Trade Museums, International Exhibitions, &c.; and this fact
is borne out by a perusal of the daily papers, in which the prominence
given to every improvement in trade or machinery attests the desire of
the reading public to know more about these matters. Here, however,
the difficulty commences, for the only means of acquiring this
information are from handbooks to the various manufactures (which are
usually too minute in detail for general instruction), from trade
journals and the reports of scientific societies; and to obtain and
systematize these scattered details is a labour and a tax upon time
and patience which comparatively few persons care to surmount. In
these volumes all these facts are gathered together and presented in
as readable a form as is compatible with accuracy and a freedom from
superficiality; and though they do not lay claim to being a technical
guide to each industry, the names of the contributors are a sufficient
guarantee that they are a reliable and standard work of reference.
Great stress is laid on the progressive developments of the
manufactures, and the various applications to them of the collateral
arts and sciences; the history of each is truly given, while present
processes and recent inventions are succinctly described.




BRITISH MANUFACTURING INDUSTRIES.




POTTERY.

BY L. ARNOUX, Art Director and Superintendent of Minton's Factory.


Without entering into an elaborate dissertation on the antiquity of
the Art of Pottery, which would be out of place in so short an article
as this, I will briefly state that the practice of making vessels from
plastic clays, for holding liquids and provisions, first resulted from
the exertions made by man to emerge from his primary condition. It is
a well known fact that vessels of clay, only partially baked, have
been found, together with stone implements belonging to prehistoric
times, and that those vessels, unfinished as they were, had peculiar
characteristics. But supposing that this was not so, it must strike
everybody that, after providing himself with those rude instruments
wherewith to obtain his food and protect his life, man must have taken
advantage of his power of observation to notice the property of
plastic clay to retain water, and to find out to what useful purpose
it might be brought for making vessels better suited to his wants,
than the skins of animals or pieces of wood roughly hollowed out. If
not probable, it is however not impossible, that the first man, taking
in his hand a lump of soft clay, should have tried to give it a
defined shape, in which case the art of pottery would be as ancient as
the human race. It may have been anterior to the use of fire, for a
sound and useful pottery may be made with clay hardened in the sun, as
still practised in Egypt and India. At all events, it existed previous
to the working of the first metal, as one can hardly understand how
bronze could have been melted, without the assistance of vessels made
of fired clay carefully selected. Consequently it is admitted by
everybody, that this is one of the earliest of human inventions, and
that the material has proved most durable. This durability, secured by
the application of heat, is a very remarkable phenomenon; for while
many other materials, apparently very hard, have been found unable to
stand the atmospheric changes or the continuous contact with a damp
soil, it was sufficient to submit this one to a very moderate heat, to
be enabled to resist these various agencies for several thousands of
years. This is particularly noticeable in the black Greek pottery,
which, while possessing all its former appearance, can, however, be
scratched by the nail or broken by a gentle pressure between the
fingers. It is thus that we are indebted to the art of pottery for
innumerable works of art, many of which have proved most useful in
elucidating historical facts, and making us acquainted with the
habits, dresses, and ceremonies of ancient peoples.

One can understand how difficult it is to decide who were the earliest
potters. It is a question that archÃ¦ologists have often tried to
answer, but which is not likely to be ever solved. Pottery was created
to meet a special want of the human race, and we find early pottery
existing in almost every part of the world, in unknown America, as
well as in Europe or Asia. It is, however, easier to decide which
people first excelled in it, and in this respect we must give equal
credit to the Egyptians and the Chinese. It is mentioned in sacred
history that more than 2000 years B.C. the Egyptian potters
were celebrated for their skill, and if we can believe Chinese
tradition, the manufacturers in China were at this same time under the
control of a superintendent appointed by the government.
Unfortunately, we have very little information respecting the history
of the art in China, previous to the sixteenth century; and although
we have a notion of what they did and how they did it, it is wiser,
with our imperfect knowledge, to abstain from speculating as to when
the different sorts of Chinese ware were produced. But as regards the
Egyptians, there is no uncertainty; some of their ceramic relics bear
their own inscriptions, and others have been found associated with
objects or monuments whose dates have been carefully ascertained. We
may well believe in their skill, when we know that they were
acquainted with the most difficult processes for making the bodies and
glazes, and that they used the same metallic oxides for colouring
their ornaments that we are now using, though often, let us
acknowledge, with less success. During a period of at least eleven
hundred years, from the eighteenth to the twenty-fourth dynasty, they
displayed considerable ingenuity in the production of small figures,
jewellery ornaments, and hieroglyphic tablets, in which several sorts
of pottery mixtures and differently coloured glazes were most cleverly
associated. It is from Egypt that sound principles of pottery making
seem to have spread to the different nations; first to the
Phoenicians, who in their turn became famous for their knowledge in
the art of vitrifying mineral substances; and then to the Assyrians,
who seem to have applied pottery more specially to the ornamentation
of their buildings.

Greece, who shortly after received her first notions of art from the
two former nations, did not devote her energies so much to improvement
of material and richness of colour, as to the refined beauty of the
shape and the excellence of the painting.

In pottery, the material is of little value, and it is only by the art
displayed in shaping and decorating it, that its price can be
increased. In this respect the Greeks proved to what enormous value it
could be raised, by making it the groundwork of their art, since sums
equivalent to several thousand pounds of our money were readily paid
by Roman patricians for a single Corinthian vase. In this, as in the
other branches of art, the recognized taste of the Greeks will never
be surpassed; and if at the present time little attention is paid by
collectors to their ceramic productions, it is probably owing as much
to the versatility of our tastes and fancies, as to our inability of
showing the articles to their advantage.

The Greeks seem to have monopolized the ceramic production of these
fine works for seven or eight centuries at the least; for although
vessels of the same description were largely produced in Italy, it was
invariably by the Greeks, following closely the traditions and mode of
decorations of their own country. It was only about a century B.C.
that the Romans began to create a pottery on which they impressed
their stamp, a pottery really their own; I mean that which is so
improperly called Samian, and so easily known by its reddish colour
and the embossed ornaments by which it is profusely covered. It is,
however, genuine and characteristic, neatly executed, and possessing
some standing qualities which did not belong to the Greek. On the
other hand, the refinement is deficient; the forms are derived from
the circle instead of the ellipse; the plain surfaces are replaced by
embossments, and the painting is absent. For four centuries, the
Romans seem to have made this class of pottery in several of their
European settlements, chiefly in Italy and in the provinces adjoining
the Rhine. In the operation they seem to have required some special
material, which imparted to its bright red surface a semi-shining
lustre or glaze, and which has proved remarkably durable. After this,
the art of pottery experienced a time of darkness, when all the
refined processes seem to have been neglected, and primitive vessels,
like those produced by the Saxons, Gauls, and Celts, ranked amongst
the best examples. The decorations, if any, are rudimentary; not only
is the painting reduced in a few instances to some lines or spots made
of a different clay, but even the embossed ornaments are replaced by
lumps of clay or impressed lines in a kind of geometrical disposition.
Art was not quite dead, but it scarcely breathed. However, these
specimens are not altogether uninteresting, for they were the first
efforts of our forefathers, and there is always a certain pleasure in
witnessing the feeblest attempts made in the research of art.

But the time came when pottery was to accomplish another revolution,
no less remarkable than the first. Strangely enough, it was again from
the East, in nearly the same province in which it originally took its
rise, that it was revived, and it is not unlikely that some faint
tradition of the old processes was the source whence sprung the new
ceramic era, which was to extend to our own time.

The precise date of this revival is not positively ascertained; but it
was probably contemporary with the establishment of Islamism amongst
the Arabs. The energy displayed by this people in improving and
adapting the different fabrics to the requirements of their new
religion, was no doubt beneficial to the art of pottery, and with
their fanaticism and spirit of proselytism, they carried their new
ideas to every country which they conquered. Syria became a great
industrial centre, and some of its towns, such as Damascus, were soon
famous for the perfection of their wares. To reach Europe, however,
this new movement did not take its course through Greece and Italy, as
in the first instance; it was through Egypt and the North of Africa
that, at the beginning of the eighth century, it made its way to
Spain, where it became firmly established. As regards pottery, nowhere
were better specimens produced than in the towns of Malaga, Grenada,
Cordova, and others, going northwards as far as Valencia and Toledo.
The newest feature of the Arabian or Saracenic pottery (called
Hispano-Moresco ware, when made in Spain) was the introduction of the
oxide of tin in the glaze, to render it opaque. Previous to this
innovation, when white was required for a design executed on a clay
which did not take that colour in firing, these parts had to be
covered with a silicious mixture, and subsequently coated over with a
transparent glaze. This was the Assyrian and Persian process. To find
a white opaque enamel, which could be applied direct on a coloured
clay and adhere firmly to it, was a great discovery.

Everyone now knows how successfully these people used pottery for the
ornamentation of their buildings, and how ingeniously they mixed
transparent and opaque enamels to obtain an unprecedented harmony of
effect. Not only did they use this tin enamel in parts, but also all
over the ware, making it more or less opaque as they wished; and this
was the origin of the pottery called _majolica_, which, according to
tradition, was imported from Majorca to Italy, at the beginning of the
fifteenth century, and for the introduction of which credit is given
to Lucca Della Robia. _Terra in-vitriata_ was the first name given by
this sculptor to his works, when they were coated with this opaque
mixture. There was at that time such an earnest desire to find
suitable materials for art decorations, that the new enamels soon
ceased to be exclusively applied to architectural purposes. Under the
beneficial influence of the revival of taste for ancient art, and the
encouragements with which it met from the princes at that time ruling
the Italian Republics, majolica attained its beauty, though its
external appearance reminded us but little of its Spanish or Oriental
origin. During the course of the fifteenth and sixteenth centuries,
the most famous in the history of modern art, the influence of the
great painters of that period was soon felt by those whom we may call
the artists of pottery, for the name of potters could hardly do them
justice; and several of them applied their talents to the reproduction,
on that ware, of their most celebrated paintings. It was reported that
Perugino, Michael Angelo, Raphael, and many others painted majolica
ware, probably on account of their cartoons being often reproduced;
and it is sufficient to say that such talented men as Francisco Xanto
da Rovigo, Orazia Fontana, and Georgio Andreoli, devoted their
energies to the improvement of this branch of art. Most of the Italian
towns had their manufactory, each of them possessing a style of its
own. Beginning at Caffagiolo and Deruta, they extended rapidly to
Gubbio, Ferrara, and Ravenna, to be continued to Casteldurante,
Rimini, Urbino, Florence, Venice, and many other places.

After the sixteenth century, majolica soon degenerated in appearance
and quality, the producers being more anxious to supply the market,
than to devote to their ware the care and attention bestowed on it by
their predecessors. In increasing the quantity of tin in their enamel,
to make it look more like porcelain, they impoverished their colours,
and this alteration, however prejudicial to majolica, assisted greatly
in the new transformation which it was subsequently to undergo. It was
under the name of faÃ¯ence that it continued to be known, and France
and Holland became the principal centres of its manufacture. At
Nevers, it still resembled slightly the Italian ware, though at Delft,
in Holland, it was principally made to imitate the blue and white ware
of the Chinese, in which attempt the makers were often remarkably
successful. At Rouen, the blue ornamentation was relieved with touches
of red, green, and yellow; at Moustiers, the monochrome designs were
light and uncommonly elegant; at Paris, Marseilles, and many other
places, the flower decoration of the old SÃ¨vres and Dresden ware was
imitated with a freedom of touch and a freshness of colour which is
really charming. This pottery, which was a great favourite in the
seventeenth and eighteenth centuries, declined rapidly soon after our
present earthenware made its appearance; the chief inducement for the
change, on the part of the manufacturers, being the excessive price of
tin, which is the principal ingredient of enamel.

Except in the provinces contiguous to France, Germany was never a
producer of majolica. It created, however, a pottery entirely of its
own, full of originality in its general appearance, and which, by the
peculiarity of the process, was really a very distinct type. I am
alluding to the Flemish and German stoneware. There is a tradition,
that the first pieces were made in Holland at the very beginning of
the fifteenth century. The principal centre of its production was,
however, in Germany, at Nuremberg, Ratisbon, Bayreuth, Mansfeld, and
other places; but the best were made in the neighbourhood of the Lower
Rhine, where the clays most fitted for that class of pottery were
easily to be found. Here we find, for the first time in Europe, the
body of the ware partly vitrified by the high temperature to which it
was submitted, and also the remarkable peculiarity, that it was glazed
by the volatilization of common salt, thrown into the oven when the
temperature had reached its climax. The combination of these two
processes had never been effected before, and it would be difficult on
that account to find any connection between stoneware and some of the
Egyptian potteries. This stoneware varied in colour: some were almost
white, some brown, others of a light grey, the last being the most
valuable when the effect was increased by blue or purple grounds,
harmonizing admirably with the foundation colour of the ware. The
shapes are generally elaborate, with a great many mouldings, enriched
with embossed ornaments in good taste, some of which were designed by
no less an artist than T. Hopfer. The decline of this stoneware began
with the seventeenth century, and from that time to the present, this
material was only used for wares of the commonest kind. It is only
very lately, that it was revived successfully by Messrs. Doulton and
Co., of Lambeth.

France, which had not as yet any ideas about the process for imitating
the Italian majolica, created towards the same time two new sorts of
pottery, one of which is the Palissy ware, the other the faÃ¯ence
d'Oiron. Palissy, a very inquisitive and intelligent man, is said to
have been possessed by a strong desire to reproduce some Italian ware,
which he had the opportunity of seeing; whether it was a piece of
majolica or of graffito, is not known. Left to his own resources--for
there was nobody to instruct him--he succeeded by perseverance and
industry in finding out the process for making the different coloured
glazes that the Moors had used long before him. There was no discovery
in this, but the talent which he displayed in the mixing and blending
of these vitreous colours, combined with the incontestable originality
of his compositions, have made this ware very difficult to imitate.

The time of its production was limited to the life of Palissy, for
there is not really a single good piece which can be traced to his
successors. In the faÃ¯ence d'Oiron, incorrectly called Henri Deux
ware, we find a real cream-coloured earthenware taking precedence of
two hundred years over our own. It was made between the years 1524 and
1567, and we have now every proof that three persons co-operated in
this invention: HelÃ©ne de Hangest, who had been formerly entrusted by
FranÃ§ois I. with the education of his son, afterwards Henry II.; her
potter at Oiron, named FranÃ§ois Charpentier; and her secretary Jehan
Bernart. The charming pieces resulting from the combination of these
three intellects were few, and only intended to be offered as presents
to the friends of the noble lady at court. This sufficiently explains
the monograms and devices, which are found associated with the
elaborate ornaments profusely spread over their surface. No ware was
ever made before or after this, which required more care and delicate
manipulation, and this explains why the highest prices paid in our
generation for an article of pottery have been freely given for
several of these curiosities. Their principal feature consists in
inlaying differently coloured clays one into the other, a process not
quite new, as it had been extensively used in mediÃ¦val times for
making encaustic tiles for the flooring of our churches, but they were
so minutely and neatly executed, and the designs so well distributed,
that they are justly considered as marvels of workmanship. In speaking
of these faÃ¯ences d'Oiron, we can hardly admire sufficiently the
variety in the productions of this period of the Renaissance; and if
we select four of these specimens, such as a piece of Faenza ware, one
of stoneware, one of Palissy, and another of Oiron, they may fairly
stand as good illustrations of the ingenuity of man.

The progress realized in these times seems to have undergone a sort of
lull, and if we accept the French and Delft faÃ¯ences, which were a
transformation of majolica, we find that the greatest portion of the
seventeenth century was not marked by any new discovery or decided
improvement. Towards its close, however, we begin to notice in Germany
and the western countries of Europe several attempts at making a ware,
possessing the three standard qualities of whiteness, hardness, and
transparency of the Chinese, and these were the precursors of the
great movement which occupied the whole of the eighteenth century. As
might be expected, inquiries made in different countries by persons
unacquainted with each other, brought different results; and if they
failed in so much, that a porcelain identical to the Oriental was not
reproduced, all of them succeeded in making a white ware of their own,
adapted to the materials which they had at their disposal. And thus
arose in each country the source of a prosperous trade.

It is only at that period, that England began to take her position
amongst the producers of pottery, at least in a manner deserving of
that name. Up to that time, if we were to judge by the quality of her
work, she did not seem fitted for it, no more than for any sort of
manufacture which required taste or a certain knowledge of the arts of
design. In fact, it is easy to notice in looking at our collections of
art manufactures, that the English samples are deficient in many
respects; they may be gaudy without harmony of colour, or elaborate
without refinement, exhibiting a certain amount of roughness in
execution, when placed side by side with Italian, French, or German
specimens of the same class. It is likely, with certain exceptions,
that the Anglo-Saxon race did not feel much the want of all those
niceties, and did not make great exertion to excel in the practice of
those arts, for the appreciation of which its mind was not yet
sufficiently cultivated. It has been remarked, that as the progress of
art was constantly from East to West, the geographical position of
England might account in some respects for her backwardness. However,
like children of slow growth whose understanding does not seem quick
or acute, but who afterwards derive the benefit of their reserved
strength, England, coming almost the last in the production of
pottery, seems as though she did so for maturing her capabilities. In
this, as in the practice of other arts, she is slow, and her first
steps are clumsy. Experimenting for some time, with mixed or
indifferent success, she seems to hesitate, till she begins to feel
that she holds the thing in her grasp, and then the day soon comes
when she teaches the world what she can make of it. We can scarcely
give her credit in the preceding review for some Staffordshire pottery
made with the yellow or red marl, thickly glazed with the galena
extracted from the Derbyshire mines, the decoration of these pieces
being effected by pouring the light clay on the dark one in a
symmetrical manner. This pottery was in use from the time of Queen
Elizabeth down to the year 1775, the date of the latest specimen that
I have seen. Some pieces preserved in the British Museum, in the
Museum of Geology, and in M. Solon's collection, are to be noticed for
their quaintness.

Up to the eighteenth century, no other clays than those extracted from
the coal measures seem to have been used in Staffordshire; and the
advantages derived from an abundant supply of both clay and fuel must
have powerfully contributed to the settlement of this industry in that
county. In Shaw's 'History of the Staffordshire Potteries,' which with
Plot's 'History of Staffordshire,' are the only books to afford
information on the then state of this trade, and whose most
interesting extracts have been given by Sir Henry de la Beche in his
excellent catalogue of the pottery exhibited in the Museum of
Practical Geology, we gather this fact, that so far back as 1661, an
Act of Parliament regulated the dimensions and quality of earthen
vessels manufactured at Burslem, for holding the butter brought to the
markets.

Towards 1680, a radical change seems to have taken place in the way of
making the ware, by substituting common salt for the galena in the
glazing process. This new production was called _crouch ware_, and
there is every probability that the substitution was first made by a
person acquainted with the manufacture of the German and Flemish
stoneware, which at a former period had been tried in England. At that
time Burslem possessed twenty-two ovens, and Shaw says, that when
these were at work, the vapours emanating from the salt were such as
to produce a dense fog in the town. These assertions leave no doubt as
to the date of the commencement of this manufacture in Staffordshire,
and that Burslem was its first seat.

Two German brothers, of the name of Elers, who settled near this town
in 1688, seem to have been the first to try to produce pottery of a
better class than the crouch ware. Their first attempt resulted in the
production of a well finished red stoneware, which probably resembled
the red ware made in Saxony by Bottger at the same time. Those who
have left any written information about it, say that for general
appearance and careful execution, it was quite equal to any similar
article made by the Chinese; but I must confess, that the specimens
that I had the opportunity of seeing are rather porous and far from
being highly baked. These foreigners paid also great attention to the
improvement of the white ware, and they were the first to employ the
plastic clay from Dorsetshire for the purpose of whitening the cane
marl of the locality. Their ware was generally light and well-shaped,
and though the plaster moulds were wholly unknown at the time, and
were only introduced fifty years later, the impressions taken from
metal moulds are neat, and show the ornaments standing sharply out
from the surface. This, combined with the peculiar appearance given to
the surface by the sublimation of the salt, and its light colour, are
the principal feature of the Burslem ware, which continued in
existence till 1780, although before that date more perfected articles
had found their way to the market. The brothers Elers used to make a
great secret of their mixtures, and left the district as soon as the
other manufacturers became acquainted with them. Astbury, who had been
instrumental in robbing them of their processes, was one of the most
intelligent amongst these potters, and it was he who, in 1720,
introduced the flint, calcined and ground, for whitening the body of
the ware, one of the greatest improvements in the making of
earthenware. He seems to have been a thoughtful and persevering man,
and it is said that the idea of this new material was suggested to
him, by seeing a shoeing smith calcining a flint, for the purpose of
blowing the dust into the eyes of his horse, suddenly afflicted with a
kind of blindness. This is probably only a fiction, as the idea must
have originated from witnessing the change undergone by flint when
brought to a red heat.

As the pottery trade was taking root in the district, it is no wonder
that we find many intelligent manufacturers doing their best to
improve it and make it profitable. Eminent amongst them was Josiah
Wedgwood, whose name as a potter is never likely to perish. For
particulars concerning his private life, trade, and manufacture, there
are two excellent books, by Miss Meteyard and Mr. Llewellyn Jewitt, in
which every matter of interest about him has been carefully entered.
Born at Burslem, in 1730, of a family of potters, he began by serving
his apprenticeship as a thrower under his brother, and must have
settled in business very early, as he had had already two partners
when he set up on his own account, in 1759, being then only
twenty-nine years of age. His first attempts seem to have been
directed to making a green ware, that is, a white ware covered with a
glaze of that colour, which he succeeded in getting particularly
bright; and also to the tortoiseshell, which had its surface mottled
with glazes differently stained, and which, by their blending when
they are fused in the oven, present some analogy with the works of
Palissy.

One of Wedgwood's decided successes was, perfecting the white
cream-colour ware, which was so superior to anything done before, that
it commanded at once a great sale at home and abroad. Queen Charlotte
admired it much, and, in consequence of her patronage, it took the
name of Queen's ware, under which it was known for a long time. It is
light, of a pleasing colour, elegantly shaped, and in the hands of
artists has proved an admirable material to paint upon.

It would take too long to enumerate all the improvements which
Wedgwood effected in his trade in the second half of the last century,
but I must mention as prominent amongst his works, the black Egyptian
and jasper wares, in making which he had no assistance whatever, and
which constitute two new and perfect types in pottery. From Wedgwood's
origin and early labours, it is easy to guess that his instruction
must have been limited; but he was a clear-minded and inquiring man,
possessing that sort of intuition by which he could easily understand
things, which in other people would have required preliminary studies;
besides, he had a natural taste for art and a systematic way of going
through his experiments, which were sure to bring them to a successful
issue. It was his good fortune to be assisted by two men of superior
intelligence, viz. Flaxman, the sculptor, who designed many of his
shapes, and modelled for him an almost innumerable number of subjects
for slabs and cameos; and Thomas Bentley, a distinguished scholar,
with whom he was commercially connected, and whose knowledge of art he
found of great utility.

When Wedgwood died, in 1795, the ceramic manufacture had extensively
developed, and had extended from Burslem to the small towns in the
neighbourhood. From all this it must appear that, although Wedgwood
was the most brilliant type amongst the English potters of that
period, the trade was already well established when he entered the
business, and there was every probability, that it would become one of
the staple industries of this country. To give all the credit to him
would be an injustice to several men, who, like the two Josiah Spodes,
effected great improvements, or brought into play new and useful
materials.

When I speak of the china manufacture, it will be seen that, besides
the Staffordshire potters, several very clever men at Bow, Chelsea,
Plymouth, Worcester, Derby, and other places, were at work to
establish the manufacture of the soft and hard porcelain, proving
beyond a doubt, that most energetic efforts were being made to raise
the pottery trade of England to the same level as that of France or
Germany. If we did not then succeed in making soft china like that of
SÃ¨vres, or hard porcelain as good as the Dresden, we soon became the
masters of the market as regards earthenware--a position that we are
not likely to lose for many years to come. Amongst the circumstances
which combine to make our position particularly strong, it is enough
to mention our independence as regards the supply of the raw
materials, and the abundance of our clays and fuel, of a better
quality than those at the disposal of our competitors. Besides, the
localization of this manufacture in Staffordshire has caused the
concentration in this spot of an intelligent population, acquainted
with the traditions, from which the different branches of the trade
can be easily fed.

The soil of Staffordshire produces a variety of clays which are used
for common ware; but the most important is the one called _marl_,
which is fire-clay from the beds of the coal measures, used for making
the "saggers," or clay boxes, in which the ware is placed before it is
sent to the ovens. The quantity required for this purpose is very
large, and it was of the utmost importance that such material should
be good, cheap, and easily procured.

At present, however, the clays necessary to make china or earthenware
are not found in Staffordshire, but are sent from the counties of
Dorset, Devon, and the Duchy of Cornwall, where they constitute an
important branch of commerce. It is a common occurrence to hear
people, visiting Staffordshire for the first time, wonder at the
apparently abnormal fact of an industry settling in a district where
none of the requisite materials are to be found. I have mentioned in
the preceding pages how it happened that the trade first settled in
Burslem; and a short explanation will show that, although more perfect
clays from distant counties had to be used, there was no need to
change.

For baking pottery, the quantity of fuel required is comparatively
large. When, independently of the ovens and kilns, we take into
account what is absorbed by the steam-engines, preparation of
materials, and warming of the shops, we find that for every ton of
manufactured goods, at least three tons of coals are wanted, and that
for decorated goods, it will take twice that quantity, and even more.
As the districts from which the clays are sent have no coals, the
advantage of paying the carriage on the smallest number of tons to be
brought to the works becomes evident.

The potter's clay derives its origin from several felspathic rocks,
which under various influences have been decomposed, and the finest
portion washed away, to be collected in natural depressions of the
soil, where it has formed beds of various thickness. Chemically
speaking, it is a silicate of alumina in combination with water, with
the addition, in small quantities, of different materials, such as
potash, soda, lime, or iron, acting as fluxes on the silicate, which
otherwise would give no signs of vitrification. The iron, which may
exist in different states, has a colouring effect injurious to the
clay, which, to be useful, must be almost free from it. When this
condition occurs, the excellence of the clay is determined by the
quantity of alumina that it contains. Pure silica, in the form of
quartz, flint, or sand, is a very easy material to procure when
wanted, but as no geological formation yields alumina in the pure
state, no other can be got, besides that which already exists in the
clays. It is a common error to say, that it is the silica which
renders them refractory. It is true that pure silica can stand any
amount of heat without fusing, but its readiness to combine with
alkaline matter, and to form vitreous compounds, renders its use
objectionable when heated with metallic oxides. An excess makes the
wares brittle and unable to resist sudden changes of temperature,
while alumina, on the contrary, gives these qualities, and with them
the plasticity required for the working of the ware. From it the clays
derive the property of absorbing and retaining a large quantity of
water, and such is its affinity for it, that sometimes a red heat will
hardly suffice to expel it completely. Alumina is a light
material--silica a heavy one; and a potter ought to know
approximatively in testing the density of a sample, whether it is rich
or poor in either of the two. The reason why the clay deposits are
richer in alumina than the rocks from which they originated, is
explained by the lightness of this element, which, being kept in
suspension in water for a longer time, was consequently carried
farther, leaving the silicious refuse to settle on its way.

For earthenware or china, the English potters use only two sorts of
clays: the ball clay, also called blue clay, and the kaolin. For
porcelain the last only is used; for earthenware, both. The ball clay,
exported from Teignmouth and Poole, comes from the lower tertiary
clays of Devon and Dorset, and is remarkably good and plastic, the
quantity of iron being comparatively very small. The ball clay from
Poole is dug in the neighbourhood of Wareham, by Mr. Pike. It is of a
very superior kind, and more than 70,000 tons are sent from that
harbour alone to the potteries, besides smaller quantities to the
Continent. As it possesses a little more alumina than those from
Teignmouth, which are dug at Teigngrace and Whiteway, near Bovey
Heathfield, they ought to have a little superiority over these,
although in practice the difference is not always perceptible.

Kaolin is the Chinese word given to the clay from which hard porcelain
is made, though here it is generally called China or Cornish clay.
This material is found in some granitic rocks in an advanced state of
decomposition; the felspar, their most important element, having under
external influence lost the greatest portion of its alkali, and become
converted into a kind of earth. By agitation in a large quantity of
water it dissolves readily; the refuse, composed of quartz, mica,
schorl, and undecomposed felspar, sinks by its own weight to the
bottom of the tank where the liquid mixture is to run; and the finest
part, which is the kaolin, is carried farther to large receptacles,
where it accumulates. When these are full, the clay is removed and
dried for export. In that state it is very white, and although not so
plastic as the ball clay, contains a little more alumina and less
iron, which accounts for its resisting much better the action of fire.
It is principally obtained at St. Stephens and St. Austell, in
Cornwall; Lee Moor, near Dartmoor, in Devon, and a few other places;
the whole of them sending to the potteries about 130,000 tons
annually.

From the same districts comes another granite, in a less advanced
state of decomposition, called Cornish stone, which is used fresh from
the mine without further preparation. In it the felspar retains its
alkaline element, so that it can be easily melted, and is found a
useful and cheap flux for the vitrification of the different mixtures.
The composition of these rocks varies considerably, so that it
requires constant experiments to determine in what proportion the
quartz and the fusible parts stand to each other.

Flints are also largely used in the manufacture of earthenware. They
are found abundantly in the chalk districts, the brown sort being
considered the best. Under a moderate red heat they become white and
opaque, and may be easily crushed between iron rollers. In that state
they are placed in pans of water and ground by large stones of chert,
till they become sufficiently divided to remain in suspension in the
liquid without sinking and hardening at the bottom of the tanks,
which, by the way, are called "arks." Flints are comparatively a cheap
material, and their carriage to Staffordshire represents a large
portion of their cost.

Such are the four materials essential for making earthenware. The
respective quantities in which they are used vary in each manufactory,
but the principle is always the same: the ball clay being the
foundation, and flint the whitening material; but as an excess of this
would make the body difficult to work, Cornish clay assists in making
it whiter and less liable to break under a heavy weight or sudden
changes of temperature. The Cornish stone is used in a small quantity
as a flux, to render the ware more compact and of a closer texture.
When the mixture of these materials is completed, the colour taken by
earthenware when fired would not be a perfect white; the quantity of
oxide of iron existing in the clays, however small, would be still
sufficient to impart a yellowish tint, particularly after the glazing
of the ware. This is counteracted by the addition of a small quantity
of oxide of cobalt, the power of which over the iron, as a staining
material, is such as to neutralize it completely; the result, in fact,
being the same as that obtained by washerwomen, who use blue to the
linen with the object of making it look white.

From the moment that the materials are extracted, to the time when the
goods are perfected, the number of distinct operations to perform is
so great, that I can only give a summary description of the most
important. The grinding of those materials which are not already in a
fine state of division is one of the most essential, for upon it
depends the soundness of the ware, and without it the difficulties of
workmanship would be greatly increased. It must be so perfect, that
when the different components are put together in the slip state, they
should mix readily and form a homogeneous compound. The grinding for
the use of potters is a trade of itself; but good quality is of such
importance, that the manufacturers who can afford it prefer having
mills of their own. In these, the different materials are ground in
water in separate pans, till they can pass freely through fine silk
lawn, and are afterwards stored in distinct reservoirs, and the excess
of water removed, so that a quart measure of each should weigh a
determined number of ounces. As the potter knows beforehand the
proportion of solid matter contained in each liquid measure, it only
remains for him to count the number of quarts or gallons which must be
introduced into the body of the ware. This being done, the liquid mass
must be deprived of its superabundance of water. Till lately it was
the custom to effect this by running the slip 10 or 12 inches thick
over the surface of long kilns, paved with bricks and provided with
flues underneath. The heat which was maintained in these, assisted by
the porous nature of the bricks, was sufficient to bring it to the
proper state of toughness; but the kilns could not be filled more than
once a day, and required besides a large quantity of fuel, much of
which was wasted in the form of dense smoke. Now, thanks to the new
apparatus of Messrs. Needham and Kyte, the same result is obtained
with great saving in space, time, and fuel.

The process is simple, and easy to manage. As soon as the final
mixture is sifted, the slip is directed to a well, whence it is raised
by an hydraulic pump and sent to the presses, which are composed of a
variable number of large wooden frames. These are closely ribbed on
both faces, and, when placed side by side in a vertical position, they
leave in the middle an interval of about three-quarters of an inch in
thickness. Each of these hollow compartments is lined with a sheet of
strong cotton stuff, folded in such a way as to form a bag, in the
middle of which a small metal fitting passes through the upper part of
the frames, and forms the spring by which the slip can be admitted
into the interior. When the bags are tied together, the slip is
admitted into their interior and submitted to such pressure from the
pump, that the water filters through the interstices of the stuff, and
escapes by the small intervals left between the ribs of the frames.
After allowing a sufficient time for the action of the pump, the
presses are dismounted, and the solid clay is found in the middle of
the bags, ready for use in the various departments.

The processes for shaping the different articles are many. For the
more expeditious preparation of the wares, it was necessary that each
workman should devote the whole of his time to a special branch of his
art. For this reason we have several classes of potters, called
according to their avocation: throwers, turners, handlers, hollow and
flat ware pressers, figure and ornament makers, tile makers,
modellers, mould and sagger makers, besides those who are employed in
the decoration of the goods. Of all these various branches, the most
attractive for those who are witnessing it for the first time, is the
throwing; and it is a source of amazement for them to see how quickly,
in the hands of the potter, the same lump of clay can be transformed
in a variety of ways.

The potter's wheel is of great antiquity. In some Egyptian
hieroglyphics from the tombs of Beni-Hassan, known to have been made
during the twelfth dynasty, the different occupations of the potter
are painted with great distinctness. In one of these, two potters are
using the wheel for making their vessels--implying that this
contrivance has been in use for something like four thousand years.
The forms and proportions of the wheels may be varied without altering
the principle. A spindle, finished at its lower end in the form of a
pointed pivot, is placed on a hard substance on which it can easily
revolve. The upper end is furnished with a wooden head or small
platform, on which the lump of clay is to be placed, and between this
head and pivot is fixed an horizontal wooden disc of large diameter,
which acts as a fly-wheel and keeps the spindle in motion for a
certain length of time. The motion may be given by the hand, the foot,
or mechanical power, which causes the spindle to revolve with great
velocity. A good thrower requires a great deal of practice, as he is
expected to throw several hundred pieces a day, although the art is
far from being what it was in the olden times. In consequence of the
new plan of pressing all large pieces in plaster moulds, the thrower
has but small or moderate size pieces to work, and these he finishes
only in the inside, leaving the outside to be done by the turner, when
the pieces are in a more advanced state of dryness. This division of
work, brought about by the exigencies of the trade, is very much to be
regretted, for the old thrower was really an artist, who could impress
his feeling on the work which was entrusted to him from beginning to
end. He has not now the same opportunity of showing his skill, and
cannot take in his work the pride and interest which he would have
felt, if circumstances had not been altered. The same may be said of
the turner, who finishes the outside on a lathe like that used for
turning wood. The thrower prepares the pieces of a thicker bulk than
is required, and it is the turner's business to bring them to a proper
thickness, by removing the excess of material and giving to the
exterior a smooth and highly finished surface. If the handles are
ornamented, they are pressed in plaster moulds; if plain, they are
squeezed from a brass cylinder, filled with clay, with a small
aperture at the bottom, from which it escapes under the pressure in
long ribbons. These are placed side by side on a board, cut across at
the required length, and bent in the form of handles when they get
sufficiently hard. They are afterwards fitted, and made to adhere to
the pieces by means of a little water or slip dropped from the point
of a brush.

Flat pieces, such as plates, dishes, saucers, and the like, are made
in plaster moulds, on which a bat of soft clay is tightly compressed
by a hand tool, called a polisher. The process is very expeditious,
although the presser is obliged to repeat the operation, to give more
pressure and finish. For this kind of ware, the potter's wheel called
a jigger, is simplified so far, that the iron spindle resting on its
point and fixed to a bench, is provided only with a round plaster head
on which the moulds are placed. The presser keeps this in motion with
his left hand, whilst with the right he guides the polisher.

In those manufactories which have adopted the latest improvements, the
jiggers are worked by steam power, and the stoves in which the pieces
are sent to dry are heated by steam pipes. These are constructed on a
new principle, consisting of a number of shelves which revolve round a
central spindle, so that by a gentle push of the hand, each section is
successively brought in front of the door, giving the opportunity of
removing or putting in the moulds. This simple contrivance does away
with the necessity for the assistant boy entering the stove, and
feeling the bad effects of the heat.

When the pieces are not exactly round, and cannot be thrown or pressed
on jiggers, it is the custom to have them made in plaster moulds,
which have been cast on models prepared for the purpose. As long as
the clay keeps soft, it takes the shape of any hard substance against
which it is pressed, and for that reason, plaster, which has the
property of absorbing moisture readily, is preferred. The use of
plaster for moulds is comparatively recent, and although its
properties were known in early times, there is no evidence that it was
ever employed for that object. Greeks, Etruscans, and Romans, had
their moulds made of fired clay; the Chinese, in raw clay thoroughly
dried. In Staffordshire, before the use of plaster, they were made of
fired clay or metal; but plaster is more economical than any of these,
although moulds made of this material do not last long, and require
constant renewing.

The making of moulds, well adapted for pressing the various shapes, is
a very important part of the potter's business. They must allow of a
certain amount of contraction, and, at the same time, must easily
dislocate without pulling away any part of the piece, which is still
sufficiently soft to be distorted by careless handling. Some pieces
will require moulds made in one or two parts; others, a large quantity
of them, the various fragments being in that case pressed separately,
and carefully put together afterwards. The pressing is done in this
way: the potter begins to flatten a lump of clay in the form of a bat,
and transfers it to the inside of the mould; then, by the repeated
blows of a sponge in his right hand, he compels the soft material to
take the exact form of the mould, and, of course, of any ornamentation
which may be on its inner surface. A good presser ought to be
systematic in his work, and not to apply more pressure to one part
than to another, otherwise the different portions of the pieces would
not contract alike, and would be liable to show an irregular surface,
or even crack in the drying or firing processes.

For several reasons, there are pieces which cannot be pressed: they
may be required very thin, or their shape is such, that the potter
cannot reach all the parts to take the impression conveniently. In
this case he must adopt the following plan. The mould is tied up, and
filled with liquid clay through an opening left in the top. The
plaster rapidly absorbs the water, and a deposit of solid clay adheres
to the surface. This soon increases in thickness; and when the potter
thinks it is sufficient, he pours out the slip which is in excess. The
piece soon hardens, and when it begins to contract, it is then time to
remove it from the mould. This process has the advantage of giving a
uniform thickness, and as there is no other pressure than that caused
by the absorption of the plaster surface, there is a better chance for
the piece to contract equally, and on this account this method (called
_casting_) is preferred for articles which require a neat execution.
In some cases it is cheaper than ordinary pressing; but the drawback
is, the excessive contraction or diminution of bulk to which the ware
thus made is subjected. An irregular contraction is the source of most
of the defects attending the ceramic manufacture, and it is worth
explaining the causes, of which there are three. I have already
mentioned that natural clays, which have remained in a damp soil for
ages, contain materials in a hydrous state, i.e. combined with water,
which sometimes increases their bulk considerably. These are unstable
compounds, and may be destroyed by thoroughly drying them. Some other
materials used in pottery may be artificially combined with water, as
would be the case, if ground in it for an unnecessary length of time.
The second reason is, the interposition of the uncombined water
between the solid particles of the clay, and as this cannot be worked
without it, this cause of shrinking cannot be avoided. It will be
easily understood, that when the water in the mixture evaporates, the
solid particles, under atmospheric pressure, will move to take its
place, and this effect will continue as long as they find enough
moisture to assist in their free motion. The consequence is, that the
mass shrinks more and more, till the contraction is stopped by the
inability of the particles to move farther; and this happens before
the pieces are completely dry. From that state to complete dryness,
the evaporation of the remaining water will leave small holes, which
will make the texture of the ware porous, and prone to absorb any
liquid with which it may come in contact.

The shrinkage in the raw state then is mechanical, and distinct from
that which takes place in the oven under the influence of heat. Under
this agency the particles enter into combination, and if the process
is carried far enough, the ware may become partially vitrified and
acquire a certain amount of transparency. The more perfect the
vitrification, the closer will be the contact of the particles, and
consequently the greater the diminution of bulk. From these causes,
the total contraction may vary from one-sixteenth to one-fifth of the
original model. The least will belong to ware pressed with stiff clay
gently fired; the greatest, to that cast with liquid slip and brought
to the vitrified state. In these last, the shrinkage is greater in
height than in width, a fact explained by the weight of the upper
portions acting vertically to assist the closer contact of the
particles in the under-structure, when the same opposes their free
action in an horizontal direction. In making the models, care should
be taken to bring the contraction to a common centre, or if there are
several, to strengthen sufficiently the connecting parts.

After the drying of the ware, the next operation consists in placing
it in saggers, which, as I have said, are made of common fire-clay,
and of a form and size to suit the different articles which they are
intended to hold. A certain thickness of flint or sand is placed at
their bottom for the purpose of giving them a firm bed, and as it is
the interest of the manufacturer to make the same firing answer for
the greatest quantity of goods, care is taken to fill the saggers as
far as is safe. The placing of the ware is done at the outside of the
ovens, and when these are to be filled, the saggers are quickly
arranged one over the other in columns, called "bungs," each sagger
forming the cover for the one immediately underneath. A small roll of
soft clay placed between makes them stand better, and at the same time
prevents the ashes carried by the draught from finding their way into
the interior, and damaging the contents.

In ancient times, the ovens, intended to hold few pieces, were very
small; but as the potters became more experienced, the sizes were
gradually increased, and now-a-days some of them are not less than 19
feet in diameter. The quality of fuel had, of course, a great deal to
do with their mode of construction. Now, however, that coals are
acknowledged to contain more heat, and to be cheaper than wood, the
ovens are generally built in a cylindrical form, with several mouths
or feeders disposed at equal distances on the outer circumference, the
upper part being covered by a semi-spherical dome or vault, to keep
the heat inside and reverberate it downwards. This construction is
very simple, the only complication being in the arrangement of flues
under the bottom of the oven, so as to throw into that part a portion
of the heat, which otherwise would be liable to accumulate towards the
top.

The firing must be conducted very slowly at first, to prevent a too
sudden evaporation of the damp, which would cause the splitting of the
goods. This being done, the heat is raised gradually, care being taken
to feed the mouths with fuel as quickly as it is consumed. It requires
an experienced fireman, to see that one part of the oven does not get
in advance of the other. He manages this by throwing in a certain
quantity of air through small openings in the brick-work, which are
shut or left open according to circumstances. Whatever may be the
construction of the oven, the quantity of air mixed with the gas
produced by the combustion of fuel causes the atmosphere to be
reductive of oxidizing; which means that the different materials
submitted to the heat would, in consequence of an abundance of carbon,
have a tendency to be deprived of their oxygen and return to a
metallic state, or that by firing in presence of an excess of air or
carbonic acid, they would be kept in a high state of oxidation. It is
fortunate that all classes of English pottery, without exception,
require, or are not injured by, an oxidizing fire, which is the most
economical way of firing, since by it all the gases are completely
burnt inside the oven without any waste of fuel. By a better
application of this principle, Messrs. Minton have introduced a new
oven, in which the fuel is so completely utilized, that it requires
only one half of the usual quantity of coals, besides doing away with
the dense smoke, which is the annoyance of the district.

By the first fire to which it is exposed, the ware is converted into
what is termed, from the French, _biscuit_--an incorrect name, as it
seems to imply that it has already been fired twice, when, in fact, it
has been only fired once. Some classes of pottery do not require more
than a single firing, as, for instance, the common terra cotta and
stoneware. However, for all our English ware it is necessary to have
two fires, for the following reasons: First, the necessity for getting
a denser texture of the ware by submitting it to a strong heat, lest
the glazes which are to be melted on their surface, and which thereby
become very dense and most contractible, should not agree with the
more open texture of the body, and should crack or craze when exposed
to changes of temperature. Secondly, that for coating the ware with
the glaze, it is necessary to dip the article in the vitreous mixture
finely ground, and kept in suspension in water; consequently, if it
were in the raw state when this was done, the adhesion of the
particles would be so small, that they would readily dissolve in the
liquid. It is customary, therefore, to expose the goods first to a
hard fire, which, according to the size of the ovens and the quality
of the ware, may last from forty to fifty hours.

From the biscuit oven, the goods, if they are to be left white, may be
sent to be glazed; but if they are to be decorated with a printed
pattern, they must be forwarded to the printing department. Printing
on pottery is comparatively a modern invention, its chief advantage
being the cheap rate of production. Up to the last century, the goods
were always painted by hand: a slow, but it must be confessed, a more
artistic process, as the work executed in this way, even of an
inferior kind, will exhibit a freedom of touch and facility of
execution, which will make it attractive and preferable to the
formality of a printed pattern, however rich or complicated it may be.
This superiority is sufficiently illustrated by comparing monochrome
patterns of Italian majolica, Delft, and Chinese, with the modern
printed ware of the same colour.

Public taste has so wonderfully improved lately, that, for my part, I
have no doubt that we shall soon have a special class of artists
trained to execute, by hand, cheap and simple decorations for those
purchasers who are not satisfied with printed decoration.

To what extent the introduction of printing on pottery has hindered
the progress of art education in Staffordshire, is a question on which
people may entertain different opinions; but we might ask, what amount
of artistic work we might not do, if at the present time we had some
hundreds of artisans trained from their early years to that style of
painting? However that may be, the process of transferring printed
patterns to biscuit ware was considered a great step, and one which
contributed largely to the extension of the earthenware trade.

Liverpool and Worcester claim the priority for this invention, towards
the year 1752. It is a fact that shortly after that date,
Staffordshire potters used to send their wares to Messrs. Sadler and
Guy-Green, of Liverpool, to be printed; and there is also every reason
to believe that about the same time it was introduced at the Worcester
works, then under the management of Dr. Wall, by an engraver named
Hancock.

The process of printing on pottery does not differ very materially
from that used for transferring to paper a design from an ordinary
copper-plate. There are, however, these differences, that a metallic
colour is used instead of lampblack, and that a fine tissue paper is
specially made for that purpose. When that paper, with the pattern
printed upon it, is laid on the ware, face downwards, the colours
adhere strongly to the biscuit, which, being porous and aluminous, has
a great affinity for the oil with which they have been mixed. After
rubbing the back of the print with a roll of flannel, to secure the
adhesion of every portion of the pattern, the biscuit piece is plunged
in water, and the paper comes off quite freely, the whole of the
colour sticking fast to the ware.

Previous to glazing, the printed ware must be brought to a red heat,
for the sole object of burning the oil mixed with the colour. This is
done in kilns, called _hardening-on kilns_.

The colours in use for printing under the glaze are not many; as few
only of the preparations made with metallic oxides can, when brought
to a red heat, stand the action of the glazes under which they are
laid. Most of them in this case will be dissolved and considerably
weakened, if they do not even completely disappear. Cobalt, and the
preparations made from chromates, are the most resisting, and, when
well prepared, the glaze in melting over them will bring out the
colour with increased beauty.

The necessity for covering the biscuit with glaze to stop the
absorption of liquids or greasy substances, which would find their way
into its interior and would stain it, is so obvious, that I do not
think it necessary to dwell on the importance of this operation. I
have stated already that it was used by the Egyptians and Assyrians,
who knew most of the saline mixtures by which white and coloured
glazes could be obtained; but these, which for the greatest part were
alkaline silicates, could not have resisted the action of time as they
have done, if a certain amount of silicate of lead had not made them
permanent. They found this material in the sulphide of lead, which by
the silica it contains, or that which it meets on the body of the
ware, gives a glaze, which stands exposure to damp better than any
other. That this mineral was used in remote antiquity, proofs are
numerous. I recollect, amongst others, some small shalti, or
sepulchral figures, made in Egypt more than two thousand years ago, of
which the red parts, such as the faces and hands, have been glazed in
this way. My opinion is, that it was used by the Greeks, in connection
with the black oxide of iron, to produce the black colour used in the
decoration of their vases, and it might some day prove that it was an
indispensable material in the preparation of the red smear, which is
the characteristic feature of the Samian ware. At all events it is
with this single material, stained with metallic oxides, that the
Arabs glazed their rich-looking pottery, and the same was used
afterwards for our encaustic tiles and our common pottery, from the
time of Elizabeth down to the middle of the last century. Lately,
however, the science of making glazes has considerably improved, and a
variety of new substances have been introduced. To prepare a glaze is
one of the most delicate operations possible, and failures are
attended with most serious consequences. The conditions to be
fulfilled are many. It must not be too fusible nor too hard, either of
which conditions would make it dull or apt to craze; and it must be
transparent, otherwise the colours underneath would not be clear. It
may happen that a glaze which apparently seems good when it comes out
from the oven, will craze when a few months, or perhaps years, have
elapsed. Generally, the less alumina that there is in the biscuit, the
easier is the adaptation of the glaze, and this accounts for the soft
porcelains being easier to manage in this respect than ordinary
earthenwares.

The materials used for the _foundation_ of glazes are in principle the
same as those for the body, viz. silica, in the form of flint, or sand
and felspar, pure or mixed with other components in the granitic
rocks, called Cornish stone. These are the hard materials to be
vitrified by the fluxes, which are carbonate or oxide of lead, boracic
acid or borax, potash or soda, carbonate of lime or barytes. There is
no definite receipt for mixing, and they may be combined in a variety
of ways. Every manufacturer has receipts of his own, and I must say
that some make their glazes a great deal better than others. They are
rather expensive, chiefly owing to the increased price of borax, a
material of comparatively modern use, which, being apt to promote the
brilliancy of the wares and the beauty of the various colours, is now
extensively used. When the components of the glazes are not soluble in
water, it may be sufficient to have them finely ground in water. But
if any soluble salt, such as borax, nitre, or soda, is employed, it is
necessary to render them insoluble, by vitrifying them together with
other substances. This may be effected in crucibles, or, still better,
in reverberatory furnaces, where a large quantity may be melted more
conveniently. In this case, when the mass is well liquefied by the
intensity of the heat, it is run into cold water, which, cooling it
suddenly, causes it to break into small fragments. This is called a
_fritt_; and when it is sent to the mill, any other insoluble
material may be added to it if necessary. To lay a thin coat of glaze
on the surface of earthenware, is a most expeditious process.
Advantage is taken of the porous nature of the biscuit, which, being
dipped in the liquid slip, rapidly absorbs the water, while the solid
particles of the glaze, which, however fine, could not follow the
water to its interior, are found coating the surface. As the pieces
are removed from this bath before the pores of the clay are saturated
with water, they are seen to dry almost directly.

After this, the last operation consists in firing the pieces a second
time, to give them that neat and finished look which belongs to glazed
substances. The saggers, ovens, and the mode of conducting the fire do
not differ in this case from those used for making biscuit. The ovens
are, however, smaller, and the saggers cannot be packed so closely
with the different articles, as every piece has to be isolated,
otherwise the glaze in melting would cause them to stick together. To
provide against this, small implements made of clay cut in different
forms are used, and, not to disfigure the ware, are contrived in such
a way that the points of contact between them and the pieces should be
as small as possible. This second firing does not take more than
fifteen or eighteen hours, and this completes the series of
operations, by which ordinary earthenware sold in the white or printed
state may be produced. The reader must understand that the majority of
these processes are also applicable to the manufacture of china, or
any other glazed pottery, with some modifications which I shall take
the opportunity of noticing, when speaking of these varieties.

Pottery may be decorated in a great number of ways, and the operations
are so varied that I cannot describe them all intelligibly, should I
attempt to do so in my limited space. I shall consequently speak only
of the paintings executed on the surface. This necessitates the use of
colours specially prepared and made from two distinct materials; the
bases and the fluxes. The bases are generally metallic oxides or
highly oxidized compounds; the fluxes are vitreous substances, similar
to the glazes, but softer, whose function is, to fix the colours
permanently on the ware. When both, after being intimately ground
together, are fired at a moderate heat on the article, the fluxes will
cause the colour of the bases to look more vigorous and brighter, the
effect being rather similar to that of an oil or transparent varnish
on ordinary body colour. For this object, they must have very little
chemical action, and be sufficiently soft to act in a moderate
quantity. If, by carelessness or accident, the temperature is raised
to a degree higher than the one exactly required, new compounds are
formed, and the alteration of the colour is the consequence. There are
some instances in which no fluxes are required; this is the case, when
the ware has been coated with a glaze sufficiently fusible to allow
the bases to sink in it, as soon as it begins to soften under the
influence of heat. By this process more force and effect are obtained.
It is, however, seldom used, for this reason, that from the care and
attention which it requires in the superintendence of the firing, the
manufacturer would run greater risks, and, being unable to use large
ovens, would not turn out the same quantity of ware. Altogether it is
a very expensive process.

Modern chemistry has placed at the disposal of colour makers new
compounds which have made the preparation of fluxes comparatively
easy. At the present time two classes are required: those in which the
oxides of lead predominate, and those chiefly made with borax, which
on account of its great purity is used in almost every flux, and is of
great service for those colours which, like the pinks and purples,
would suffer from the presence of lead.

The preparation of painting colours is a little more complicated, and
each requires a different treatment. The number of those found in the
trade is rather large, and each artist has his favourite maker. In
this, as in any other kind of painting, beginners are apt to think
that they will be assisted by the use of a great variety of tints,
when they will learn by more experience, that a very limited number is
sufficient. I cannot undertake to give any receipts for those who
might wish to prepare these themselves; I only mention the name of the
substances necessary to secure each of the essential colours.

White is not a colour, but when wanted on a coloured body, it is
procured by an enamel prepared with the oxide of tin. Light yellow
requires the oxides of lead and antimony. Orange will require the
same, with an addition of deutoxide of iron. The hydrate of peroxide
of the same metal will give a golden buff. The subchromate of lead
gives a very bright red, but it is very unsafe and mixes badly; the
reds made by calcining the common sulphate of iron are preferred. From
this, according to the degree of fire, all shades of red may be got,
from an orange red to a deep purple brown. The pinks, purples, and
crimsons are made from the precipitate of cassius; this is obtained by
pouring a weak solution of tin in the chloride of gold. The dark blue
is a triple silicate of cobalt, which, by the admixture of the white
oxide of zinc, may be converted into a brighter blue. The green oxide
of chrome is the base of all greens, the tint of which is modified by
cobalt for the blue greens, and antimony for the yellow greens. The
chromate of iron, a mineral coming in large quantities from South
America, is the base of all browns. The black may be got from the
mixture of various oxides, but the best is that made from the oxide of
iridium. Besides the above, there is another class of colours in which
the oxides are thoroughly combined with the fluxes, such as the greens
made from copper and the transparent blues, which are ground colours,
and must be classified with the glazes. When painting colours are
fired with their respective fluxes, they are very permanent, and will
not only resist ordinary atmospheric influences, but also the action
of every gas or mineral acid (the fluoric excepted). This seems an
advantage in favour of painting on pottery, and one which ought to
give them an additional value; in reality, however, artistic merit
ranks above all other considerations, and unless the work is original,
connoisseurs in pottery will hardly take this into account.

Several oils possessing drying properties, such as those of lavender,
aniseed, or turpentine, are mixed with the colours, which, from the
fact of containing vitreous substances, would work badly; even with
their assistance, it requires a certain amount of skill to master the
process. We must not make too much, however, of this difficulty,
generally exaggerated by the ignorance of apprentices in what
constitutes the very principles of their profession. When parents, in
perfect ignorance of the abilities of their son, have decided, after
putting their heads together, that he shall be a painter, sometimes
for no other consideration than that they can get him admission into a
porcelain manufactory, or that this is the nearest to their home, the
boy has not the least notion of what is before him, and hardly knows
that he will have to learn that very difficult thing, drawing. No
wonder then, if his deficiency in this will not allow him to produce,
we will not say good, but saleable paintings, unless he has spent a
dozen years on his trial. On the contrary, to one well prepared by the
study of art--one who, before he sets to his work, has a clear
conception of the effect which he wishes to produce--the process will
not stand in the way, and he will master it in the course of a few
weeks.

To induce talented men to devote their time to the decoration of
pottery, is perhaps the greatest difficulty met with by our leading
manufacturers. As long as the making of the ware only was concerned,
they had to call for the assistance of practical men, such as potters,
chemists, or engineers, the number of whom is fortunately great in
England, and whose services can be secured by money. The same thing is
not so easy in the matter of art. Up to a recent date, painting on
pottery was not considered as the high road to fortune, and artists
preferred to try their chance in oil or water-colour painting, fully
aware that they would have to fight against an army of competitors,
and to be satisfied with very small incomes, unless, by their, then
problematic, genius, they could cut their way to the front. Since,
however, the rage (there is no other word for it) for well decorated
pottery has spread in almost every class of society, the prices paid
for good work are more remunerative, and artists like Solon, Mussill,
and Coleman, can make artistic pottery their special business.

Royal Academicians like Poynter and Marks have thought it not beneath
them to prepare cartoons for Minton, and it is probable that others
would follow in the same path if, with the assistance of our chief
potters, they could be initiated into some of the mysteries of the
craft. No doubt they would find the study attractive, and there is no
fear that, having once begun, they would not keep faithfully to it.
For myself, I know of no such example.

In addition to the painting colours, there are a few metals which are
used to enrich pottery; unfortunately, the number of those which can
undergo exposure to a red heat without oxidizing is very limited.
There are only three, viz. gold, silver, and platinum, which can stand
it, and, among these, silver is of little use, on account of its
proneness to tarnish under the action of sulphurous gases. Gold, on
the contrary, affords to the decorator one of his greatest resources.
We cannot say when the Chinese began to use it; we only know that in
Europe it was thought a great discovery, when, in the sixteenth
century, it was used in the Italian majolica. From that time to the
introduction of hard and soft porcelain in Europe, it was rarely and
sparingly used; and it was at Meyssen, soon followed by the other
continental and English manufactories, that they began to use it
extensively. At the present time, its annual consumption by our
Staffordshire potters alone represents a very large sum of money.
There are several ways of preparing gold for pottery purposes; the
oldest consists in grinding gold leaves on a slab, adding to it gum
water, honey, or any other mucilaginous liquid. This laborious process
surpasses all others; it has a very artistic effect when used thin, in
the Chinese fashion, and, when laid thick, as we find it in the Old
SÃ¨vres ware, it answers beautifully for chasing; the only drawback is
the expense. The most usual way is to have it amalgamated with
mercury, and afterwards ground in turpentine; it has then the
appearance of a blackish substance, which will regain its colour, as
soon as the mercury is volatilized by the application of a gentle
heat. When it comes out of the kiln, the gold is dull, and requires to
be burnished with agate and bloodstone tools, to be in possession of
all its brightness.

There is another decorated pottery, called lustre ware, now out of
fashion, but most successfully executed at one time by the Moors, the
Persians, and the Italians on their respective majolicas; the glaze of
this ware being more favourable than any other for the display of the
process. It simply consisted in painting over the fired ware with the
protoxide of some metal, such as that of copper, taking care that from
the moment the kiln began to get to the red heat, a constant supply of
thick smoke should be kept up. The partial reduction of the metal
which adheres to the surface has a very pleasing effect, as may be
noticed in the large Hispano-Moresco dishes, considered the finest
specimens of this class. Those produced in Italy by Georgio Andreoli
fetch, however, a higher price, on account of the redness of their
colour; the process is fully described in the celebrated manuscript of
Piccolo Passo, now in the library of the South Kensington Museum.
Lessore, the French painter, lately dead, and M. de Morgan, in London,
have succeeded in producing very fair specimens of that kind. Some of
our Staffordshire potters can make another lustre by mixing chloride
of gold with lavender oil, sulphur, resin, and other carburated
ingredients, and laying this mixture very thinly on the surface of the
glazed ware; the iridescent pinkish colour which it takes when it is
fired in an ordinary kiln is rather peculiar. This has no connection
with the old process, and is only used for the commonest kind of
goods.

The kilns in use for firing the painted or gilt ware, are called
muffles or enamelling kilns; they are in the form of a D, laid on its
straight side, and of a length proportionate to the size and number of
pieces which they are to hold. The fireplaces are arranged on one of
the sides, and the flues contrived in such a manner, that the flame
should travel round the whole of the outer surface, great care being
taken that it should not have access to the interior through any
cracks or joints which might exist in the brick-work. For ordinary
goods one firing may suffice; for those highly decorated, as many as
five or six may be necessary.

Let me now say a few words respecting the various wares produced by
our English potters.

The first earthenware made after the time of Wedgwood and Josiah Spode
was far from being so good as that made at present, and several
attempts were made to bring out a pottery which should be intermediate
between earthenware and porcelain. The most successful was that made
by Mr. Mason, of Fenton, who, in 1813, took out a patent for an
ironstone china, the body of which was fluxed by the scoriÃ¦ of
ironstone and the ordinary Cornish stone. But eventually this last was
found sufficient for that purpose. The name of ironstone remained to
that class of pottery which is strong and resistive. Since then,
however, earthenware has so much improved, that ironstone has gone out
of fashion; the nearest to it is the ware called _white granite_,
made for the American market, which is richly glazed, and made thick
to compete with the French hard porcelain, which is also exported to
the United States for the same class of customers. About fifty
manufactories are specially engaged in producing this ware; and those
in the occupation of Messrs. Meakin, Shaw, Bishop and Powell, and G.
Jones, may be considered the largest. The best earthenware is made for
the home market, some of which is so perfect that, if it were not
opaque, it might be mistaken for porcelain. When it is richly
decorated and gilt, like that made by Messrs. Minton, Wedgwood,
Furnival, Copeland, Brown-Westhead, Brownfields, and several other
leaders of the trade, very high prices are obtained for it.

Some of these makers do not devote all their attention to earthenware,
but produce other classes of pottery. Amongst the sorts which are most
connected with earthenware are majolica, Palissy, Persian ware, and
flooring and wall tiles. I have given the name of majolica to that
class of ornament, whose surface is covered with opaque enamels of a
great variety of colours. It is only connected with the Italian or
Moorish in this respect, that the opacity of the enamels is produced
by the oxide of tin; but as we have not in England the calcareous clay
for making the real article, we have been obliged to adapt, as well as
we could, the old processes to the materials at our disposal.

At present, English majolica is very popular, and without a rival for
garden decoration, as it stands exposure to the weather better than
ordinary earthenware, besides the impossibility of the latter
receiving the opaque enamels without crazing or chipping.

Majolica was produced for the first time by Messrs. Minton, in 1850,
and they have been for many years the only producers of this article.
It is only five or six years ago that Messrs. Maw, of Broseley, in
Shropshire (and very lately the Worcester manufactory), have made a
pottery of the same kind. The name of majolica is now applied
indiscriminately to all fancy articles of coloured pottery. When,
however, it is decorated by means of coloured glazes, if these are
transparent, it ought to be called Palissy ware, from the name of the
great artist who used these for his beautiful works. Messrs. Wedgwood,
George Jones, and a few other makers of less importance, are
reproducing it more or less successfully. To Messrs. Minton, however,
we owe the revival of the ware, which, in connection with their
majolica, created such a sensation in the French International
Exhibition of 1855; and credit must be given to those gentlemen, for
being on that occasion the promoters of that demand for artistic
pottery, which has so largely developed of late. It is to satisfy this
craving for novelties, that they have undertaken the imitation of the
faÃ¯ence d'Oiron, better known by the name of Henri Deux ware, a rare
and costly one, which can only be produced in small quantities; and
also their most recent improvement, the reproduction of the Persian
wares.

In the old Persian pottery we find a real earthenware taking a
precedence of several centuries over our own. There is little doubt
that it can be connected with the early Arabian, Assyrian, and
Egyptian, by the similitude of the processes common to all. I have no
room to explain how it is that, being an earthenware, it is so much
richer in colour than the modern ware made on this side of Europe. I
can only mention that the body of the Persian ware may be converted
into a transparent porcelain by firing it hard, which shows that the
sandy clays from which these are made are sufficiently saline to
become vitreous. To this they owe the property of receiving, without
crazing, glazes of the softest kind, and consequently of exhibiting
those colours which can only stand at a low temperature, such as the
Persian red, the turquoise, and that purple or violet which makes so
valuable the specimens on which it is laid. If we had in England sandy
clays like those which abound in Persia, the reproduction of Persian
ware would have been an easy undertaking; but in trying to
reconstitute it by synthesis, there were several obstacles. Within the
last three years, however, Messrs. Minton have sold a great many
specimens of the ware, some of them of very large size. They may be
recognized by the depth of the turquoise, which is sometimes as rich
as SÃ¨vres pieces of the best period. Their only competitors for this
class of pottery are the manufactories of Worcester and of Messrs. Maw
and Co.

I cannot leave earthenware without mentioning the plain and encaustic
tiles, articles of comparatively recent manufacture in England, but
whose consumption is increasing so fast, that it may be expected in
time to afford a most valuable compensation, should circumstances
restrict the production of some other branch of the trade. There is no
need to dwell on the advantages offered by the use of tiles. They are
clean, invaluable in a sanitary point of view, free from further
deterioration and expense for maintenance, and susceptible of a
variety of treatment which makes them admirably fitted for decorative
purposes. To the Eastern nations we owe the idea of using ornamental
tiles, and it is likely that it is from the numerous buildings
existing in Western Asia and the north of Africa, at the time of the
Crusades, that our forefathers took the notion of introducing in
Europe the encaustic tiles; their ceramic knowledge being too limited
to undertake the making of painted or enamelled tiles, an essentially
Saracenic and Moorish production, whose specimens nearest to us are
those to be seen in the Alhambra, or in the Alcazar at Seville. An
inspection of those made afterwards in Spain, in the time of Charles
V., or in Italy for the Vatican, and some of the palaces in Genoa,
would prove that they were made exactly in the same way. From the
contrast between the opaque and transparent enamels, these tiles have
a very forcible and harmonious effect, not to be met in others (the
Persian excepted, though these, exclusively decorated on a cool scale
of colours, cannot answer so well the requirements of modern
architecture). The majolica and Delft tiles, chiefly the last, have
been almost exclusively used during the seventeenth and eighteenth
centuries, and it is only within the last forty years, that we began
to make them in earthenware. With the revival of this manufacture, and
of almost any other sort of tiles, the name of Herbert Minton is
closely associated. It was during his time, and with the assistance of
Mr. Michael Daintry Hollins, that this great undertaking was carried
out with such success, that hardly a new church or public building is
erected where these tiles are not introduced. The making of plain
tiles is new and peculiar. They are made from dry clay reduced to
dust, which, being submitted in metallic moulds to a pressure of
several hundred pounds to the inch, becomes so compact, that further
contraction is almost suppressed, and they can be handled without risk
of breaking. Encaustic tiles are made from plastic clay, in which the
different portions of the design are sunk below the surface, so as to
form recesses, in which slips of different colours are poured
according to a set pattern. When these become as hard as the body of
the tiles, the surface is made smooth and level with a steel scraper,
which removes all the superfluous material, till the colours are shown
standing neatly side by side with the greatest precision. It is a
pretty process and interesting to witness. Besides the flooring tiles,
there are many other sorts made for lining walls and fireplaces,
varying considerably in style and material. There are two very
extensive and perfected tile works at Stoke, viz. those belonging to
Mr. Hollins and the Campbell Brick and Tile Company, in both of which
all sorts of flooring and wall tiles are made. In the second, recently
built, Mr. Colin Minton Campbell, the proprietor, has introduced new
arrangements and contrivances in almost every department; all
operations being performed on the ground floor, and in such manner
that the goods shall travel the shortest possible distance from the
moment they are begun to that of their completion. He has been the
first to use Maw's patent steam presses for plain tiles, each of which
can make twelve thousand tiles weekly, requiring only the assistance
of a single person, to remove the tiles as they come out from the
mould. It is by the intelligent use of these mechanical processes,
that we may expect a reduction in the price of such a useful article.
The firm of Mintons still continue to make their plain white printed
and artistic tiles, along with their patent process for painting on
mosaics. The Broseley Works, in Shropshire, belonging to Messrs. Maw
and Co., have also a great name, and carry on an extensive business in
tile making. Next are those of Messrs. Edge and Malkin, of Burslem.
Messrs. Simpson, of London, are well known for their wall decorations
in tiles painted by hand, and Messrs. Copeland, of Stoke, for their
painted slabs.

The various porcelain biscuits known under the name of Parian or
statuary biscuits, are specially used for statuettes, busts, and other
articles for which it is desirable to get the appearance of white
marble. This is a kind of hard porcelain made from a mixture of kaolin
and felspar, in which the degree of hardness or fusibility is
regulated by the proportion of one material towards the other. Of
course, similar biscuits may be made by more complicated receipts, but
the principle is always the same, viz. the taking advantage of the
fusibility of felspar or Cornish stone, to secure the required amount
of transparency. The light being allowed to penetrate to some depth
below the surface, imparts to these biscuits a softness which is
wanting in the similar productions of SÃ¨vres, Germany, and Denmark.

In noticing the bluish-white colour of the foreign article as compared
with the cream tint of our own, I must explain that this difference
lies in the management of the fire, since in none of them is stain or
colour introduced to procure any such result. As my readers must now
understand, there is in all clays, pure as they may be, a certain
amount of oxide of iron, which, during the firing process, forms
silicate of protoxide or peroxide, according to the chemical
composition of the atmosphere of the oven in which they stand. On the
Continent, to make hard porcelain successfully, the fire must be
reductive; while here, on the contrary, it is oxidizing; and it is to
the formation of a small quantity of silicate of peroxide of iron
disseminated in the mass, that the creamy colour of our Parian is due.
Since this new material was introduced by Messrs. Copeland and Messrs.
Minton, about twenty-eight years ago, a large quantity of figures,
busts, and groups have been sold, and the talent of our most eminent
sculptors has been put to contribution to get models adapted for this
kind of ware. Parian is generally cast, which accounts for the great
contraction it undergoes when fired, and much care is required for
propping or supporting the various articles, as neglect or
miscalculation in this respect would inevitably ruin them. Otherwise,
as this biscuit is made from few materials and takes but one single
firing, the simplicity of the manufacture has induced many small
makers to undertake it--a fact that we should regret, if we were to
take a purely artistic view of this subject. Parian, which was
originally sold in biscuit state, has since been glazed, for the
purpose of making pieces of decoration. The manufactory at Worcester,
several years ago, made a great many coloured and gilt ornaments in
the Cinque-cento style, to which it has lately added a highly artistic
imitation of the Japanese lacquered ivories, for which great credit is
due to the present director, Mr. Binns.

The Belleek manufactory, in Ireland, has obtained a name for coating
its glazed Parian with an iridescent lustre, in imitation of a similar
article invented by a Frenchman, M. Bianchon.

For richly decorated ornaments, the body of the Parian has been
stained with success in many rich colours by Messrs. Minton, their
last production in this class being a Parian combining the red colour
of the terra cotta, with the advantages of a vitrified porcelain.
Their most artistic ware is, however, their _pÃ¢te sur pÃ¢te_, in
the production of which they have been assisted by M. Solon, an
eminent artist, who left the SÃ¨vres works to establish this branch of
fine art in their manufactory. To carry on this process, advantage is
taken of the transparency of the Parian body with which the figures or
ornaments introduced in the composition are painted, or rather
modelled. As they are laid on a ground of a dark colour, the softness
of the shades in the thinner parts gives to the finished pieces a
particularly beautiful cameo appearance. The effect may be compared to
that of the Limoges enamels, when confined to the white colour. This
process has a certain connection with that of Wedgwood for making his
jasper ware; but there is this difference, that in the jasper, the
figures and ornaments are taken from clay moulds, and may be repeated
to any extent, the talent of the artisan consisting in pressing neatly
and transferring on the vases the various fragments of decoration,
without destroying the sharpness of the impression, while in the _pÃ¢te
sur pÃ¢te_ original works can only be produced by the artist, who must
combine the qualifications of designer and modeller. What I say here
is not in disparagement of jasper, which, considering the time of its
introduction, was far in advance of anything that could be expected.
In its production the Wedgwoods never had a rival, and the models of
the celebrated Josiah Wedgwood are still worked at their manufactory
at Etruria, with the same success. The sulphate and carbonate of
barytes were the fluxes originally used to vitrify the body of the
jasper ware, and on this account it ought to be classified with the
stoneware. Parian, which may be made from purely granitic materials,
has a nearer connection with porcelain.

There are three different sorts of porcelain: 1. The Chinese and
Japanese, with which may be assimilated the German and French, all of
them made of kaolin and felspar, sometimes with an addition of quartz.
The principal seat of this manufacture is now in France, with Limoges
for its centre. 2. The soft porcelain, of which the most perfect type
is the old SÃ¨vres, includes those of Chelsea, Bow, Worcester, and
Derby. In all these the transparency, which is the distinctive feature
of porcelain, is secured by the introduction of _fritt_, a mixture of
sand and alkaline materials thoroughly vitrified, ground and made
workable by an addition of plastic clay. The calcareous marl used at
SÃ¨vres gave to the French works a superiority over the English, who
could only use the clays from our southern counties. The manufacture
of the soft porcelain, on account of its difficulties, is almost
abandoned. 3. The English porcelain, the body of which is made, like
the hard, from kaolin and Cornish stone, but differing from it by the
addition of a large proportion of calcined bones. This kind is
exclusively English. For the hard porcelain, the glaze is made from
felspar containing a variable quantity of quartz, or, as in Germany,
from quartz vitrified by an addition of gypsum, the melting of which
in both cases requires a very high temperature. For the glazing of the
two other classes of porcelain, a soft, vitreous mixture containing
silicate of lead and borates is used, the temperature necessary to
melt these being much inferior to that required for firing the biscuit.

The most ancient porcelain is, as everyone knows, the Chinese, which,
relying on the few authorities that have written on this subject, may
have been in existence for two thousand years, and is said to have
reached its greatest perfection towards the eleventh century of our
era. The Portuguese have the credit of having been the first to
introduce it in Europe, in 1520; but it is not improbable that, before
they doubled the Cape of Good Hope, some specimens were brought to
Europe through India and Persia. This may be inferred from the mention
by ancient historians of some extraordinary white vessels, which could
hardly correspond to any other kind of ware. The Portuguese and the
Dutch, who were the first to explore the Chinese seas, seem to have
derived a good trade from the importation of the porcelain into
Europe, and, since then, the reproduction of that refined pottery was
the ambition of many alchemists, who pursued their experiments in that
direction with an eagerness almost equal to that wasted in the search
for the philosopher's stone. For a long time, in consequence of the
imperfection of their chemical knowledge, their efforts ended in
failure. The only successful attempt was that of Francis II., one of
the Medicis, who produced a few pieces of soft porcelain recognizable
by their mark, representing the dome of Florence.

At the death of this prince, his secret was lost, and it was a long
time afterwards, at the end of the seventeenth century, that John
Dwight, a potter, of Fulham, in Middlesex, took a patent for what is
curiously reported by Dr. Plot as "_the mystery of transparent
earthenware commonly knowne by the name of porcelaine and Persian
ware_." Made from English materials, it is probable that this was
nothing better than a kind of white stoneware, possessing little of
those qualities which would entitle it to the name of porcelain. Next
to that in date would be the soft porcelain made at the manufactory of
St. Cloud, which was said to produce, in 1698, pieces of ware
considered very good imitations of the Oriental. This was the origin
of the French soft porcelain, which was carried on afterwards with
varied success at Chantilly, Vincennes, and other places, till it was
definitely settled, in 1756, by King Louis XV. in the royal
establishment of SÃ¨vres. At a corresponding period, on this side of
the Channel, the efforts of our potters were varied and numerous. If
we are to believe Dr. Martyn Lister, a manufactory of porcelain
existed at Chelsea as far back as 1698, a fact which would establish
for England a claim equal to that of France for the discovery of the
soft porcelain. This is not altogether improbable, considering that
there was a glass manufactory in that locality before that, and that
many people had a notion that porcelain was nothing else than a glass
hardened and made opaque. The managers of these glass-works may have
experimented on that supposition, and the conjecture is strengthened
by the fact, that pounded glass was always used at Chelsea to give the
desired transparency. Good specimens are not, however, recorded before
1745, and it is probable that many of the improvements at Chelsea were
realized by the Staffordshire potters, who, two years later, went
there to apply their industry. The priority in making practically good
ware belongs to the works established in 1730 at Stratford-le-Bow,
from which the Bow porcelain took its name. It was not perfected
there, however, before 1744, when a china, softer than that made at
Chelsea, and nearer to that made at Vincennes, was manufactured by a
potter named Frye, originally a painter, who seems to have been the
promoter and manager of these works, which at one time did not employ
less than three hundred people.

Bow was celebrated for its statuettes, and it is said that several of
them were modelled by Bacon, the sculptor. The successes of Bow and
Chelsea were great but of short duration, for both had ceased to exist
in 1775, when their utensils and moulds were sold to Mr. William
Dwesbury, and carried to Derby, where this enterprising gentleman had
started a manufactory as far back as 1751.

Three generations of Dwesbury continued here the traditions of
Chelsea, after which time the works became the property of Robert
Bloor, the last owner of repute. I am happy to say that after ceasing
to exist for a great many years, this celebrated manufactory is going
to be revived under the leadership of Mr. E. Phillips, formerly one of
the directors of the Worcester works. In that same year (1761), a
man--who for his inquiring turn of mind and artistic knowledge seems
to have a great likeness to Josiah Wedgwood--Johu Wall, a doctor and a
chemist, began also to make porcelain at Worcester; and if Mr. Binns'
assertions are correct as regards the preparation of the fritt used in
it, he must have had some knowledge of the Vincennes receipts. The
Worcester works have now been celebrated for more than a century, and
with them must be associated the names of the various owners, Flight,
Barr, and Chamberlain. At Caughley, in Shropshire, a manufactory of
soft porcelain was in existence in 1756, and it was employed at one
time by the proprietors of the Worcester works to assist in making
ware, which was sent back to them to be decorated. The Caughley works
were bought by John Rose, a pupil of Turner, the first director, and
transferred to Coalport, with which the works of Nantgarw, in South
Wales, were also amalgamated. These works have been in the family of
John Rose until lately, when they came into the possession of M. Pew,
the present owner. For softness and resistance of body, brightness of
glaze, and clearness of colour, the Coalport ware is held in great
esteem by those who know anything about china. At Swinton, in
Yorkshire, soft porcelain was manufactured on the property of the
Marquis of Rockingham. Manufactories also existed at other places, so
that the reader may here remark, that all exertions to establish the
manufacture of china were made outside Staffordshire; and if he has
noticed the dates, he will also perceive that all these works were
founded, when Wedgwood was too young to render any assistance. This we
must say in justice to Dr. Wall, Frye, Dwesbury, and Cookworthy--whose
name must not be forgotten as the discoverer of the Cornish clay,
which so greatly promoted the ceramic trade of this country. William
Cookworthy was a chemist and druggist, at Plymouth, a member of the
Society of Friends, and a man of great respectability. Having had the
opportunity of seeing some kaolin and felspar from Virginia, that an
American friend had shown to him as the very material from which the
Chinese porcelain was made, he recognized, several years afterwards,
the same in Cornwall, and setting resolutely to work, he began to make
his first trials at St. Stephens, on the property of Lord Camelford,
and afterwards at Plymouth, where he remained till 1774, when
Champion, a merchant of Bristol, bought his patent, and removed the
works to the latter place. I must here explain that Cookworthy's ideas
of the making of porcelain were correct, inasmuch as he wished to
closely imitate the Chinese; consequently he had to work on different
principles from those then in favour at Chelsea and other places. He
wanted to produce a porcelain without fritt and with a felspathic
glaze, and, in succeeding in his attempt, this energetic man is
entitled to a great deal of credit, when we consider that, although
the processes discovered by Bottger, in 1710, at Meyssen, for making
hard porcelain, were also put in practice at Vienna, St. Petersburg,
and Berlin, they were kept very secret, and it is most probable that
he had no information whatever from those quarters. It would be to rob
Cookworthy to admit that the hard porcelain pieces, known by the name
of Lowestoft, were made in that locality. I am indeed sorry to differ
in this from an eminent critic, who has taken great trouble to collect
documents in support of this opinion; but those who are in favour of
it know very little about the difficulties attending the organization
of such manufacture, and the quality of the materials that it
requires. Besides the absence of any information respecting the place
whence these materials were taken, the vast quantity of pieces which
are met with is such, that it precludes the idea that they have been
made in the precincts of such a small establishment. They have every
feature of Chinese porcelain, and of one made in large quantities. It
is most probable that, after making, or trying to make, soft porcelain
for a time, the proprietors of the Lowestoft works found it more
profitable to paint and decorate the foreign article, which they could
easily get from Holland in the white state.

Most pieces of Cookworthy manufacture were copied from the Chinese,
and are still well known by the name of Plymouth porcelain. At
Bristol, Champion used the same clay to produce a softer kind of ware,
and his materials began to be employed at Bow and other places. The
Staffordshire potters soon became anxious to take advantage of the
discovery, and in 1777 a company was formed by Jacob Warburton to
obtain a licence for their use. This was granted by Champion, but with
this singular restriction--that, although they were allowed to use a
certain quantity of china clay and china stone, they were not to make
porcelain. This restriction, however, did not last long, and Champion
himself came for a short time to Shelton to superintend some works.
Amongst the names of Warburton's associates, we notice some well known
in Staffordshire, such as S. Hollins, of Shelton; Antony Keeling, of
Tunstall; Turner, of Lane End, and a few others. To these gentlemen we
must give credit for the earliest attempts to introduce the
manufacture of china into the Potteries. However, their porcelain was
inferior to that made at Worcester and Derby, and it is doubtful
whether they would have persisted, if the matter had not been settled
by Josiah Spode, the second of that name, who, by adding calcined
bones to the body of the ware, made a new kind of porcelain, distinct
from the hard or the soft previously made. On that account Spode
deserves to be considered as the creator of the English porcelain.
There is this peculiarity in the use of bones, that the phosphate of
lime which enters into their composition is not decomposed by the
silicates with which it is mixed, and, as it is infusible, its
admixture in the body allows the ware to stand without injury the
temperature at which the felspar is vitrified. This hardening of the
bones does not exclude a certain amount of transparency, and they
possess, besides, a very great advantage in preventing the oxides of
iron which exist in the clays, producing that brownish or imperfect
transparency, noticeable in the old Derby or Worcester ware. I have
already said that the adaptation of the glaze for each kind of pottery
is one of the greatest difficulties that the maker has to overcome; in
this case, however, there was very little, and the glazing of English
porcelain may be considered as exceptionally easy. Most of the glazes
which had been used for the soft porcelain could be adapted to this
one, a property which was of great service when the pieces had to be
decorated. I have already explained, that when paintings executed on
the surface of the ware are submitted to a moderate red heat, if the
glaze is soft enough to undergo an incipient fusion, the vitreous
colours with which they are executed will sink into it and attain, by
their incorporation, an amount of glossiness and brilliancy which
cannot be got on the surface of hard glazes. This is particularly
illustrated by the old SÃ¨vres ware, which possesses this quality in
the highest degree. English porcelain, well-made, has almost all the
advantages of the old soft, and its making is not attended with the
difficulties experienced in working a body made from fritted
substances. For regular use, it is not much inferior to the hard
porcelain. When this last began to be made on the Continent, people
were so much prejudiced in its favour, on account of the capability of
its glaze to resist the scratching of the knife, that this was thought
to more than compensate for its inability to combine with the colours.
The advantage was, in fact, more apparent than real, for when hard
porcelain has been long in use, it becomes as badly scratched as the
English. Some people question whether it would not be desirable to
revive in England the manufacture of the hard. There are many reasons
against this, the principal being, that in case we succeeded, we
should have to compete with the French and Germans, who get their
labour cheaper, and have a long experience of processes altogether
different from ours; and by the change we should lose the advantage of
our traditions, and depend, at least for a time, on foreign labour to
give a new training to our workmen. Out of the trade, few people seem
to know that the price of hard porcelain is generally lower than that
given for the English; and, if the experiment were made, it would be
soon found that with greater risks we should produce an article of
less value, and consequently less remunerative. It is true that the
exports of our best china are very small, on account of its price; but
with the improvement going on in the public taste, it is likely to
increase, and there are signs that eventually our richest articles may
find purchasers on the other side of the Atlantic.

In Europe, where the value of the various ceramic productions has been
more investigated than in the other parts of the world, there is
hardly an amateur who does not recognize the superiority of a soft
porcelain for decorated articles, and if the English china is not,
properly speaking, as soft as the old SÃ¨vres, it is certainly nearer
to it than any other porcelain. This superiority is proved by the test
that the various porcelains are undergoing at the present time, and
which is rather decisive. We understand by this, the manner in which
they have stood the dangerous competition arising from the
introduction of artistic faiences or painted majolica. While, in
consequence of this, the French manufacturers have seen the production
of ornamental articles in hard porcelain collapse to an incredible
extent, the quantity of those made in England for similar purposes is
fast increasing.

Messrs. Copeland, whose father, the late alderman, was for some time
in partnership with Spode, occupy, in Stoke-upon-Trent, the same
establishment in which that great potter carried out his improvements.
Since then, these makers have kept their rank among the principal
leaders of the trade, and maintain their reputation for the excellence
of their decoration and the beauty of their gilding. It was so far
fortunate for Stoke that, although one of the smallest towns in the
Potteries, it became the seat of the most important manufactories of
china. It was in 1788 that Thomas Minton, who had been brought up as
an engraver at the Caughley works, in Shropshire, and who in that
capacity had been several years in the employment of Spode, founded in
that town the establishment which subsequently became the property of
his son, Herbert Minton. The father does not seem to have possessed
these qualities which, as potter, should entitle him to a special
notice; but the same cannot be said of the son, who soon after his
father's death began to work in earnest to raise his manufactory to
its present degree of eminence. The unceasing activity of his mind in
carrying out improvements in all the branches of his trade, may be
attested by one who for many years had the honour of working with him.
On every matter connected with art his ideas were sound, and his
natural tact rarely failed in finding out that which was most suited
to the taste of his customers. His reputation, as the most advanced
potter of his time, is so well established, that I am not astonished
to find others claiming a share in it, asserting that it was at their
suggestion, or with their assistance, that he left the old path to
open the way to progress. Suggestions and advices are always freely
given to a man of sociable disposition as was Herbert Minton, but he
used his own judgment and discretion to test their practicability. In
applying higher class of art to his productions, he had only to follow
his own inclinations, guided by that care and prudence which are
inseparable from good administration. He knew how to select his
assistants, and was particularly fortunate in his partners, his two
nephews: Michael Hollins, who, since he left the firm of Minton, is
the owner of a large tile manufactory at Stoke; and Colin Minton
Campbell, his pupil and heir, who, after taking an active part in all
his labours, has so successfully followed the example set by his
uncle, that Minton's manufactory is now the largest in existence, and
turns out the greatest variety of ware. With Minton and Copeland must
be associated the names of Messrs. Brown-Westhead, of Caulden Place;
and outside Staffordshire, the Coalport works and the Royal
manufactory at Worcester. These are the principal producers of richly
decorated china, for which the demand has greatly increased during the
last few years. The greatest bulk of that ware is, however, made at
Longton, one of the pottery towns which has a reputation for the
cheapness of its goods; but of late a decided tendency to improve
their quality and prices must be noticed among the generality of its
manufacturers. Several of them, like Messrs. Ainsley, Moore, Barlow,
and others, are trying to raise their goods to the same level as those
of Stoke. There are about thirty-five firms in the Potteries making
china, most of them for the home trade, and over five times that
number making earthenware. These two hundred and thirty manufactories
are spread over an area of ten square miles, comprising the towns of
Hanley, Burslem, Tunstall, Longton, Fenton, Shelton, and
Stoke-upon-Trent, from which the electoral borough takes its name.
These, which in a few years are likely to be amalgamated in a single
town, form the district called the Potteries, containing already a
population of 170,000 inhabitants engaged in the ceramic and iron
trade. It has been remarked that since the foundation of Burslem, the
mother town of the Potteries, the population of the district has
doubled every twenty-five years, and it is easy to foresee the time
when Stoke-upon-Trent will rank in importance with our largest
commercial cities.

The export of porcelain is not large; but that of earthenware reaches
one and a half million of pounds. This does not appear large compared
with the enormous amount exported by the iron or the cotton trades,
but it is satisfactory, if taken in combination with the quantity
absorbed by the home trade, which represents quite as much. Our
colonial trade with Australia, India, and British America is decidedly
on the increase, and the same may be said as regards South America. On
the contrary, our transactions with the Continent of Europe have a
tendency to decrease, and to fluctuate in the case of the United
States, a very important market, which, in time of prosperity, would
take as much as 800,000_l._ of granite ware.

To meet the competition of France and Germany, on one side, and the
Americans on the other, great changes have taken place in the
management of our works. Several processes have been improved or
simplified, and large manufactories have been built on better
principles. These steps were not taken too soon; for if competition
scarcely existed for our goods twenty years ago, that state of things
has been much altered, and it will require a great deal of application
and energy on our part, if we intend to maintain our position as the
largest and best producers of pottery in the world.

It is a fact that America, which had not a single manufactory worth
the name at the time of the New York Exhibition, produces now, with
the assistance of British workmen, granite ware of tolerably good
quality; and I have been told by an eye-witness, that no less than
seventy ovens are now at work at Trenton, in New Jersey. The clays and
coals used by these potters are good, and if the salaries are higher
than they are in England, they find a compensation in the heavy duties
which, since the war of Secession, are levied on our wares.

Our commercial intercourse with France has not much altered, and the
quantity of our goods sent across the Channel may be considered small
compared with the importance of this market. The French are the
largest producers of hard porcelain, and they make their common
earthenware quite as cheap, if not cheaper, than ours. However, if
they are strong at home, they have never affected our trade abroad,
except in the United States, where they send their porcelain in
competition with English granite.

At the present time, the rivalry from which we have suffered most in
Germany, the North of Europe, and as far as Italy, comes from a group
of establishments situated in the Rhenish provinces and that
neighbourhood: at Sarreguemines, Sarrelouis, Vaudrevange, Mettlach,
Maestricht, and a few other places. Built in the centre of a populous
district, where labour is still very cheap, their intelligent and
wealthy proprietors share in each other's business, and consequently
have no inducement for lowering their prices. They seem to have given
a considerable portion of their time to the study of the various
processes, and they have so far succeeded, that they are a great deal
more independent with regard to their men than we are. Possessing
these advantages, we cannot wonder, if we have not been able to keep
our hold on those markets which were the nearest to them. Besides, it
is plain, that the important rise which has taken place in the price
of wages and fuel, and the consequent increase in the price of our
wares, has acted as an encouragement to foreign production; and
perhaps it may be good policy, in future, to resist any further
opportunity which might offer to increase the price of our goods. It
would, however, be singular if, in the course of time, England did not
derive some benefit from this competition; she is used to close
contest, and, everything considered, her position is an enviable one.
Our home trade is excellent; and if the amount of our exports does not
progress so fast as we could desire, we know that we have in our
commercial fleet more facilities that any other nation for sending our
goods to those numerous countries where the trade of pottery is hardly
established, and we rely on our honest and straightforward way of
dealing, for securing new customers for English manufacture.




GLASS AND SILICATES.

BY PROFESSOR FREDK. S. BARFF, M.A.


The very brilliant and useful substance, which forms the subject of
this article, is said to have been discovered by the Phoenicians.
The story goes that some Phoenician merchants, while cooking their
food on the sands near the seashore, noticed that the ashes of the
plant, with which they made their fire, caused some of the sand to
melt and form a vitreous substance; but whether this tale be true or
not, it is well known that for a long time these people made glass
from the materials which were abundant on their sea and river coasts.

Glass, however, was produced long before this by the Egyptians for the
beads and ornaments used in adorning their mummies, and many specimens
of these are in the British Museum. It is certain also that they well
knew how to make certain substances impart colour to glass for the
manufacture of most of these beads. The Romans made rich goblets of
ruby glass, some of which are to be seen in collections in this
country, as well as urns to receive the ashes of their dead, four of
which, of a green colour, are also in the British Museum. The
manufacture of these vessels proves that this nation was well skilled
in the arts of blowing and modelling glass; and their designs, which
we are now reproducing, show that they were at least not inferior in
artistic skill to those who have formed their taste in this highly
civilized age. We have no record of glass being used for glazing
purposes in ancient times. The Venerable Bede introduced it into this
country about 674 A.D., and employed it in the adornment of
church windows. Ordinary window glass was made at the works in
Crutched Friars in 1557, and plate glass at the large works of the
Ravenhead Plate Glass Company, near St. Helen's in Lancashire. About
1776, flint glass vessels were blown at the establishment in the Savoy
House; and the second Duke of Buckingham brought over Venetian
artists, at that time the most skilled, to make glass for mirrors,
carriage windows, and other useful purposes. Their workshop was in
Lambeth, and the date of their arrival in this country was 1673. The
French were before us in the art of casting glass plates; and in 1688,
Stewart commenced this branch of manufacture, which led to the
establishment of the very famous works of St. Gobain. England has now
large plate glass factories in different parts of the country, and
these together yield as their weekly production at least 140,000
superficial feet of the best polished plate, or seven and a quarter
millions of feet yearly. The value of plate glass made in England
annually, including the rough kinds used for glazing roofs, &c., is
estimated at 1,000,000_l._ France still stands very high, and her
plates are extremely perfect in manufacture. St. Marie d'Oignies, in
Belgium, also sends a considerable quantity of plate glass into the
market. This branch of manufacture has not yet extended to America,
which therefore is a large customer of Europe. Formerly, glass making
was very heavily taxed in this country, and in 1812 an additional duty
was placed on the manufacture of the raw material, which so greatly
depressed it, that the income which the State received fell from
328,000_l._ to 183,000_l._ per annum. Moreover, large quantities of
foreign glass were imported, and this too hindered the development of
the industry amongst us. On the repeal of the duty, however, the trade
began to increase, and has now reached very large dimensions.

Glass appears to be a mixture of silicates, the nature and chemical
composition of which will be explained in a later part of this
article.

The materials used are principally sand, with an alkaline substance,
either a salt of soda or potash and lime, though in some kinds of
glass, oxide of lead takes the place of lime. Other materials are
generally employed to correct impurities which may occur in the sand,
and which, if present, always impart an objectionable colour to the
glass.

There are two kinds of glass in ordinary use: common window glass,
which may be divided into sheet, crown, and plate; and flint glass,
which is used for decanters, wine-glasses, and tumblers; and, in some
special forms, for ornamental stones in imitation of jewels, and also
for lenses of telescopes and microscopes. The materials for making
these different kinds vary somewhat, although the principal
constituents are the same, viz. sand with some salt of soda or potash.

The scientific name for sand, or more properly for its principal
constituent, is silica. This compound silica, or oxide of silicon,
also called silicic acid, possesses properties similar to those which
belong to other acids, namely, it is able, when brought into contact
with bodies of an opposite character under suitable conditions, to
unite with them and to form salts. Everybody knows, that if tartaric
acid be added to carbonate of soda, an effervescence takes place;
carbonic acid passes off in the gaseous state, and the residue is
composed of a portion of the tartaric acid, which unites with the
soda, a double decomposition taking place. If silicic acid be mixed
with carbonate of soda, and if the mixture be heated to a high
temperature, that is, to a white heat, for some length of time, the
same kind of action occurs: carbonic acid goes off, the silica or
silicic acid uniting with the soda; and inasmuch as the soda salt was
originally called _carbonate_ of soda, after this action, in which
carbonic acid is replaced by silicic acid, it is called _silicate_ of
soda. Silicic acid at the ordinary temperature of the air and in the
dry state, has no action whatever upon carbonate of soda, but when
heated sufficiently, the action becomes vigorous. A very interesting
experiment may be performed in illustration of this fact in the
following manner: if a mixture of carbonate of soda and carbonate of
potash be heated in an ordinary fire-clay crucible, and if, when the
mixture is melted, some perfectly dry sand be poured into it,
effervescence will take place, owing to the expulsion of carbonic acid
from the carbonate of soda and potash by means of the silicic acid. If
the operation be performed in such a vessel that the carbonic acid can
be collected, its presence is readily indicated by the usual tests.
This experiment can be easily made by anyone who has ordinary chemical
apparatus at his command. If the mixture of carbonate of potash and
carbonate of soda be melted in a small platinum crucible; and if, when
melted, it be removed quickly while very hot into a tall beaker-glass,
and sand be then poured into it, the escaping carbonic acid will, on
account of its being heavier than air, be retained in the glass, and
its presence can be recognized by its turning lime-water milky (which
is, in fact, a solution of lime in water), owing to the formation of
carbonate of lime produced by the carbonic acid evolved uniting with
the lime dissolved in the water. A mixture of carbonate of soda and
carbonate of potash is here used, because either of these salts
requires a very high temperature to melt it; but when the two are
heated together, the fusibility of both is increased. When sand is
heated with oxide of lead (common litharge) they unite, forming a
compound similar to that produced by the silica uniting with the soda,
as described in the last paragraph. In the first case, a _soda_ glass
is formed; in the second, a _lead_ glass is the result. If these two
glasses be mixed together and melted in a crucible, and if the
proportions in which they are mixed be properly adjusted, and the
materials used be pure, a colourless and transparent glass will be
formed, similar in appearance to that which is employed in the
manufacture of decanters and tumblers. The same kind of glass may be
produced by mixing all the materials in due proportions and heating
them together. If, instead of oxide of lead, lime be mixed with
carbonate of soda and sand, and the mixture be heated to a high
temperature, a glass will be formed, in many respects similar to that
of which oxide of lead is a constituent, but differing from it in
several important particulars. First of all, the lead glass is highly
lustrous, and has a great power of refracting light, so that, when it
is cut, it presents a brilliant appearance, and by refraction readily
produces the prismatic colours. This property does not belong to the
glass containing lime, to anything like the same extent. Lead glass,
too, is much heavier than lime glass, and is therefore unsuited to
many of the purposes for which the latter is generally used, the
principal of which is for the glazing of windows.

If, instead of oxide of lead, which is a chemical compound of lead and
oxygen gas, or lime, which likewise is one of the metal calcium with
oxygen, _carbonate_ of lead or of lime be used, the silicic acid will
expel the carbonic acid from these substances at a high temperature,
just as it does the carbonic acid from the carbonate of soda and
carbonate of potash. It is necessary, for a proper understanding of
the scientific part of our subject, that this fact should be borne in
mind, and that the acid properties of silica should be thoroughly
recognized. Formerly, carbonate of soda was used in the manufacture of
ordinary window glass, but now it is found more economical to employ
_sulphate_ of soda, which is a much earlier product in the manufacture
of soda from common salt than the carbonate, and is therefore less
expensive. Carbonic acid is what chemists call a _weak_ acid, by which
is meant, that its compounds are not so firm and stable, as those
which are formed by other acids with the same substances. Sulphuric
acid is a strong and powerful acid, uniting very readily with the
oxides of certain metals to form very stable compounds. But although
this acid is chemically so powerful in its compounds, yet at a high
temperature it is expelled by silicic acid, showing that this
substance, so inert in its natural state and at the ordinary
temperature of the air, becomes exceedingly active in expelling other
acids and in forming compounds, when put under favourable conditions.

If a mixture of common sand and carbonate of soda, the carbonate of
soda being in excess, be heated, a glass will be obtained which is
slowly soluble in cold, readily soluble in hot water. To these
compounds the name of silicate is given, so that we speak of the soda
compound as silicate of soda, of the lead compound as silicate of
lead, and the lime compound as silicate of lime. Silicate of soda and
silicate of potash, when the alkali, that is to say, the soda or
potash, is in excess, are both soluble. If a solution of one of these
silicates be taken, and if carbonic acid be passed slowly through it,
after a time a gelatinous, white, flocculent substance will be formed
in the liquid, and eventually precipitated. This white flocculent
substance is silicic acid combined with the elements of water, and is
therefore called by chemists hydrate of silica. Now this hydrate of
silica is soluble in water and in hydrochloric acid; and the method by
which it can be brought into solution in water will be explained, when
treating fully of what are called soluble silicates and their
applications.

Soluble silicates are mentioned here, in order that a more perfect
understanding of the nature of silicious compounds may be obtained, by
those who do not possess a scientific knowledge of chemistry. The
silicic acid in the silicate of soda is precipitated or separated out
by carbonic acid, and hence it appears, that an action, exactly the
reverse of that which takes place at a high temperature, occurs, when
the silicic acid is removed from those conditions in which it has been
seen to be (chemically) so active.

Suppose that to a solution of silicate of soda or of potash a soluble
salt of calcium be added--the chloride, for example, which is a
compound of the metal calcium with chlorine--a double decomposition
will take place; the calcium will unite with oxygen in the silicate of
soda, forming lime; and this will again unite with the silicic acid,
forming silicate of lime; while the chlorine will unite with the
sodium, forming chloride of sodium, or common salt.

Here then, silicate of lime is obtained by a process very different
from that which has already been described, namely, by the heating of
lime with silica at a high temperature. The body formed in the latter
case is chemically the same as that produced in the former, there
being present the same weight of calcium, the same weight of oxygen,
and the same weight of silicic acid in each. Again, if to a solution
of silicate of soda, one containing a soluble lead salt, such as the
nitrate, be added, the silicic acid will unite with the oxide of lead
in the nitrate of lead, and the acid constituent of that body will
unite with the oxide of sodium or soda, forming nitrate of soda. It is
apparent, therefore, from these remarks, that in whatever way the
substances be made to unite, the effects produced as regards chemical
composition are the same. If some of the silicate of lime or silicate
of lead made by precipitation be dried and heated to a high
temperature in a crucible, it will melt or fuse, and form a vitreous
substance. In these last cases, as in many others which will have to
be alluded to, the silicates formed are not soluble in water, although
silicate of lime may be partially dissolved when heated in water under
extreme pressure, by which the temperature is considerably increased,
and even slightly in cold water.

To ensure the production of definite silicates by the agency of heat,
the materials must be mixed together in proper combining proportions;
for if more of the metallic oxide is introduced than can combine
chemically with the sand, it will be melted in the mass, but the
excess will not form a definite compound; whereas by precipitation,
the silicates formed always have, when thoroughly washed, a definite
composition. This subject will be again referred to, when the
manufacture of commercial glass is described.

It has been noticed that the glass found in the windows of old
churches and in other places where it has been exposed to the
prolonged action of the air and of moisture, has gradually become
rough on its surface, and has lost to a considerable extent its
transparency. This, which would be a defect in glass for the glazing
of ordinary windows, where transparency is desired, is rightly
regarded as a beauty in glass which is to be used for the
ornamentation of windows. Many reasons have been offered in
explanation of this apparently peculiar property of ancient glass; and
that which appears to be correct is, that glass is a mechanical
mixture of different silicates, some of which may be soluble in water,
and others insoluble. The old window glass, whose manufacture will be
more fully described by-and-by, was made in a less perfect manner than
modern appliances enable glass manufacturers now to produce the same
article, so that the silicates composing the old glass were not as
intimately mixed as those used in modern glass. By the slow action of
air and moisture, portions of the soluble silicates have been
dissolved out, and hence we frequently find a sort of honeycomb
appearance on the surface of ancient glass, as well as a thin film,
which, by refraction of light, causes an opalescence when viewed by
reflected light. Efforts have of late been made to produce a similar
effect by employing different methods in the process of manufacture,
but without complete success. The fact, however, that such changes
have taken place in this less perfectly fused glass, tends to show,
that if one silicate can be dissolved out, there cannot be _chemical_
union between all the silicates. If a piece of modern window glass be
heated in water under pressure in a closed vessel, it will present
somewhat the appearance of ancient glass, for a considerable quantity
of soluble silicate will be dissolved out from it. The object in
dwelling on this matter here, is to induce makers to attend more to
the chemical composition of their glass, for, doubtless, much more
satisfactory results would be obtained both as to the quality of the
material and the cost of its production, if thoroughly scientific
investigations were conducted by a competent chemist.


MANUFACTURE OF GLASS.

The first object in glass making is to obtain suitable materials. The
sand which is employed for window glass differs from that which is
required for flint glass, in that the latter should be as pure as
possible. The maker can correct the impurities in the window glass
sand, provided they be not present in too great quantities; but it is
far more difficult, in the case of flint glass, to chemically
counteract the influence of those substances which might impair its
tint. So that the manufacturer would rather pay large prices for his
sand, than trust to expedients which in their application might fail,
and thus cause a greater loss.

One of the principal and most troublesome impurities met with in sand,
is iron in the form of oxide. There are two oxides of iron: one, the
protoxide, which imparts a green colour to glass; and the other the
peroxide, whose staining property is yellow. A very small quantity of
the former will give an appreciably green tint, whereas it requires a
large quantity of the peroxide to produce even a delicate yellow. In
all glass making, it is found necessary to use something which will
counteract the colouring properties of these two oxides. The material
employed was black oxide of manganese. This is still used in certain
glass-works, but from its injurious action on the fire-clay pots,
arsenious acid or common white arsenic is employed to effect the same
object. The chemical action in the two cases is different: the black
oxide of manganese is what is termed an oxidizing agent, and gives up,
at a high temperature, a portion of its oxygen to the protoxide of
iron, thereby converting it into the peroxide. It thus becomes
comparatively harmless, by converting a quantity of that oxide, which
gives a green colour, into the other oxide, which has little or no
power of colouring, except it be present in large quantities. The
difficulty in using black oxide of manganese is, the exact
proportioning of it to the quantity of iron present in the sand, a
quantity which cannot be easily determined. If the black oxide of
manganese be used in excess, some of the oxide of manganese remains
unreduced, and, when this is the case, it gives a purple colour to
glass. If used in exact proportions, it is reduced to an oxide which
does not impart colour to glass. This may be seen in many of the old
plate glass windows which were employed for glazing purposes some
sixty or seventy years ago, the colour of the panes being generally
purple.

Since this article was written, I have been consulted by a glass firm
of eminence, as to the use of pure black oxide of manganese in the
manufacture of flint glass, instead of that ordinarily supplied in
commerce. The black oxide of manganese usually sold contains many
other constituents besides black oxide of manganese; amongst these are
iron, copper, cobalt, and alumina.

The iron, as will be seen from what has before been stated, is a
decidedly objectionable ingredient to use along with the manganese.

Copper and cobalt both stain glass, the former of a bluish-green
colour, while the latter makes it blue; and a small quantity of the
latter has great staining power. I have thought it advisable to give
analyses of the black oxides of manganese, and they are as follows:

Binoxide of manganese (Molecule, Mn.O_2), is found native as
pyrolusite or polyanite. Appended are two analyses of pyrolusite
containing sesquioxide of iron.

  Red oxide of Manganese  87Â·0  72Â·5
  Oxygen                  11Â·6   9Â·8
  Sesquioxide of Iron      1Â·3   4Â·2
  Alumina                  0Â·3
  Baryta                   1Â·2
  Lime                     0Â·3
  Silica                   0Â·8   1Â·4
  Water                    5Â·8   1Â·6
                         -----  ----
                         108Â·3  99Â·5

The native binoxide often contains both copper and cobalt in addition
to iron; frequently to the amount of as much as 1 per cent. of copper
and about Â·54 per cent. of cobalt.

Wad, a native binoxide of manganese, sometimes contains 54Â·34 per
cent. of iron, while nearly all the manganese ores contain more or
less alumina, varying from Â·5 per cent. to as much as 20 per cent.

From the composition of ordinary commercial black oxide of manganese,
as shown by these analyses, it is evident that it is better to use the
pure article, and this has been found to be the case by the firm who
have adopted it in lieu of commercial black oxide of manganese. I
therefore strongly recommend all glass makers to try and experiment
with it, for the results obtained will largely counterbalance the
extra cost of the pure material; and I also much doubt whether the
same injurious effects will be produced on the pots, as is the case
where commercial manganese is employed.

Arsenious acid also acts as an oxidizing agent, in that it gives up
its oxygen to the protoxide of iron, converting it into the peroxide;
but the arsenic itself, which has lost its oxygen, is reduced to the
metallic state, and being volatile, does not remain with the glass,
but passes off by the flues of the furnace. If too much arsenic is
used, it sometimes renders the glass milky or cloudy.

Before describing in detail the method of mixing and founding glass,
it will be necessary to mention the composition of the vessels in
which the glass is made. They are called glass-pots, and differ in
shape according to the different kinds of glass to be made in them.
Glass-pots are made of fire-clay (generally the best Stourbridge),
which is a silicate of alumina, and here great care is taken to select
that which contains least lime or iron. It is ground, then moistened
and well kneaded together, and left to ripen, while a certain quantity
of old glass-pot is ground fine and mixed with the fresh fire-clay.
Masses about the size of two hands are kneaded separately, the object
being to exclude all air bubbles, and to obtain a perfectly
homogeneous lump. The bottom of the glass-pot is then laid, the masses
of fire-clay being pressed in with the greatest care, so as to avoid
all cracks or places where air might enter during the slow process of
drying.

The modern shape is round; though formerly certain glass-pots, called
_cuvettes_, used in the purifying of plate glass, were square. Pots
used in the manufacture of common crown and sheet window glass,
generally speaking, are larger at the top than at the bottom; but
whatever may be the shape of the pot, the method of its building is
the same. The sides are carefully made of fire-clay, each piece being
laid on by itself and kneaded like the bottom of the pot, so that it
is slowly built up until it reaches the desired height. It is then
dried very gradually, and the process is finished in artificially
warmed chambers. Before putting it in its place in the glass-furnace,
it is allowed to remain for some time in what is called a pot-arch,
that is, an archway built of fire-clay bricks, along the side of which
is a fireplace, by means of which the arch is brought up to a red
heat; and after it has been heated sufficiently, is removed while
red-hot and put into the furnace. Glass-pots are never allowed to
cool, and with care they may last for several months. From this
description of their manufacture, it will be clear that it is attended
with considerable cost, varying from 5_l._ to 10_l._

There are three different kinds of ordinary pots for crown, plate, and
flint glass; and of these the last is decidedly the most expensive, as
its top is covered over, and presents the appearance of a dome with an
opening in front, through which the materials can be introduced when
the pot is charged, and from which, when made, the glass may be drawn,
in order to be blown into shape by the workman. In glass-furnaces the
pots are sometimes arranged in a circle, with their mouths opening
into the glass-house; but now a different construction is sometimes
employed, since other methods of heating the furnaces have been
introduced. It is hardly within the scope of this article to enter
into a description of glass-furnaces; suffice it to state, that they
should be of such a construction as to yield the greatest amount of
well-regulated heat for the smallest consumption of fuel, and this
object seems to be best effected by the adoption of Mr. Siemens'
excellent principle of heating furnaces. For some years his process
has been in use at the Thames Plate Glass Company's Works, where the
saving of fuel has been very considerable, and the glass greatly
improved, owing to the fact that impurities from the fuel employed
cannot possibly find such easy entrance into the glass-pot. In any
case, the construction of the furnace is such, as to be best adapted
to the convenience of the workmen, according to the kinds of glass
which they have to make. Differently arranged furnaces are used for
bottles from those employed for crown and sheet glass.

It has lately come to my knowledge that flint glass, that is to say,
the glass used for tumblers, decanters, and such like, is occasionally
injured by the appearance in it of little opaque white spots. Some
portions of glass of this character have been analyzed by me, when I
found that these white spots were owing to the presence of a glass
containing alumina. Now alumina raises the melting point of any glass
of which it is a constituent. So, then, these white spots were due to
the presence in the flint glass, which was perfectly clear, of a much
less fusible glass which was only partly made when the flint glass was
ready for working. On investigating the matter, it was found that the
alumina came from the glass-pots, for when by my advice the faulty pot
was withdrawn from the furnace and carefully examined, although it had
been in work only six weeks, the bottom was honey-combed to a very
considerable extent, showing that portions of the pot had been
dissolved; and inasmuch as the fire-clay, of which the pots are made,
contains a large quantity of alumina, it was not difficult to trace
the source of these white spots which had rendered useless much very
valuable glass. On inquiry it was found that the pots had been made
entirely of new clay, and on reference to the book of workings, which
was kept in the glass-house, it was also found that for some time, the
glass-pots used in that establishment had been made of new clay, and
that on a previous occasion a similar calamity had before happened.

In the records kept where pots were made, as has already been
described, with a portion of old pot as well as new clay, no white
spots had ever appeared in the glass. It is therefore manifest, that
it is much safer to use a portion of old pot than to trust to pots
made entirely of new clay.

Having considered briefly the manufacture of glass-pots, I shall
proceed to the treatment of the materials to be employed. In making
common window glass, ordinary sand, which does not contain any very
large quantity of iron, may be used, the alkali employed being
sulphate of soda, while the purifying material is either arsenic or
black oxide of manganese. A small quantity of anthracite coal is added
to the mixture, in order to assist in the reduction of the sulphate of
soda, together with some lime. The materials are carefully mixed and
placed in the furnace, where they are heated for some time, a process
which is called "fritting." Its object is to perfectly dry the
materials, so as to expel carbonic acid gas, which would otherwise
cause swelling in the glass; but no combination must take place, to
allow of silicates being formed, otherwise the alkali would melt first
and attack the substance of the glass-pots, and part of it would be
volatilized and lost. When this operation is completed, the fritt is
put into the hot glass-pot, and submitted to the action of the heat of
the furnace, until the glass is made, or "founded," as it is
technically termed. In the case of sheet and crown glass, this process
lasts from sixteen to seventeen hours, for it will be remembered that
the top of the pot is open to the furnace, so that the flames pass
over the surface of its contents. In this way the materials get heated
more rapidly than when a covered glass-pot is used.

M. Gehlen gives as a good mixture for window glass:

  Sand                  100 parts.
  Dry sulphate of soda   50   "
  Quicklime              20   "
  Carbon, as charcoal     4   "

Different makers have different mixtures. This by M. Gehlen is given
as _about_ the proportions of the several constituents employed.

The charging of the pots is conducted in this manner: they are filled
with lumps of fritt, and the heat of the furnace is raised as rapidly
as possible, until, in about eight or nine hours the fritt has run
down or melted into glass. More fritt is then added, which also melts,
and from time to time this is repeated, till the pot contains a
sufficient quantity. After about sixteen hours the whole has become
converted into glass, and the surface of the molten mass is covered
with liquid salt and sulphate of soda. This scum is called glass-gall
or sandiver, and is carefully removed with iron ladles. Some broken
glass, or cullet, is now thrown into the glass-pot, a little at a
time, the object being to cause any salt which may remain in the pot
to rise to the surface, which is then removed, and so the glass is in
this manner purified, after it has been further heated for some hours,
to expel gases.

When the glass is made, and its temperature so reduced that it is in a
doughy or pasty state, it is then worked off by the blowers into
either sheets or tables, as is desired. The blowing of sheet and crown
glass is a work of considerable difficulty and labour, and one which
cannot be successfully performed, except by a workman who has been
brought up from boyhood in a glass-house. A quantity of the soft glass
is collected or gathered on the end of a blowpipe, and the workman
then blows into it, and distends it into a globular form. Now it is
necessary, in making sheet glass, that that globular form should be
elongated; the workman therefore holds his blowpipe, which is about
five feet long, in a vertical direction, and the softened globe
becomes pear-shaped. By dexterously swinging the blowpipe from side to
side, which he does while standing on a plank placed over a sort of
pit, and by causing it to rise on either side, he converts the
pear-shape into a true cylinder, having rounded ends. When the
cylinder has assumed the exact shape desired, he places his thumb on
the end of the blowpipe, and holds the opposite end of the cylinder in
the mouth of the furnace. The glass softens at the heated end, and the
expanding air causes it to burst the opening. It is then shaped with a
suitable tool, so that it is of the diameter of the cylinder. When the
latter is cooled, a piece of hot glass is applied to its shoulder with
a pontee, and is drawn out into a thread around it. This makes the
glass hot. The thread of glass is removed, a cold instrument is
applied rapidly, and the shoulder of the blowing is cut off. The glass
is next detached from the blowpipe, and its ends removed, and it is
then annealed for a short time, and cut down lengthways internally by
a diamond. It is afterwards placed, with the long cut uppermost, in
what is called a flattening kiln, that is, in a sort of oven or
furnace heated to a high temperature and having a perfectly smooth
stone floor; after a short exposure the glass softens, and a workman,
with suitable wooden tools, opens it out where it was cut by the
diamond, and causes it to lie flat upon the stone. It is then rubbed
by a wooden tool, and in this way is flattened, removed from the
flattening stone kiln, and placed in a hot chamber, in which it is
allowed to cool slowly, for the purpose of "annealing."

Sheet glass, formerly called broad glass, was originally made on the
Continent; but its manufacture, first established in this country by
the introduction of foreign workmen, has extended to very large
dimensions, and the quality of English sheet is now quite equal, if
not superior, to anything that is produced abroad. The advantage which
it possesses over crown glass is, that much larger sheets can be made,
and this is very easily noticed if we examine the larger dimensions of
common window panes compared with those which were formerly made. Even
now the workmen employed in this class of manufacture are generally
Belgians. A sheet glass blower must be very strong, and have great
skill in handling his blowpipe, for the cylinders which he blows are
frequently sixty inches long, and their weight is very considerable.
Glass shades are blown by sheet blowers. These sometimes are very
large, and require great skill. When their shape is to be that of a
cylinder with a dome top, they are made as in the ordinary course of
blowing a cylinder of sheet glass, but instead of one end being burst
as described, they are simply detached from the blowpipe. When they
have to be oval or square at their bases, they are blown into wooden
moulds of the required form, which have their insides charred. The
gathered mass of glass is placed inside such a mould, and is then
blown into until it touches the sides. This is an operation requiring
great strength and delicacy; strength to blow with sufficient force to
bring the softened glass to touch the mould in all its parts, and
delicacy to prevent the pressure from being so great as to cause the
outside of the glass shade to receive marks on its surface from the
mould.

The shaping of the molten glass into tables of _crown_ is different in
detail. The globular mass formed by the first blowings is held by a
workman vertically over his head. An assistant gathers a small
quantity of soft glass from the furnace on the end of a pointed iron
rod, and causes it to adhere to the flattened surface, at a point
opposite to that to which the blowpipe is attached. The glass near the
blowpipe, while hot, is touched with a cold instrument, and
immediately cracks around its neck, detaching the blowpipe from the
mass. The pointel is taken by the blower, and the opening formed by
the removal of the blowpipe is placed opposite to what is called a
"flashing" furnace, that is, a furnace with a large circular opening
in its front, and which is heated to such an intense degree, that it
is impossible for a person unaccustomed to it to approach within
several feet of the furnace-mouth. The workman generally wears a
shield or screen to protect the upper part of his body and face. The
glass becomes softened by the heat, and the workman gives his pointel
a rotary motion, somewhat similar to that which a housemaid gives to a
mop when she trundles it; and as the glass softens, the opening gets
larger and larger, until at last the softened mass instantaneously
flashes out into a circular sheet, an operation which produces a very
startling effect upon the eyes of anyone beholding it for the first
time. The circular crown table thus made is detached from the pointel,
and the mass of glass which caused it to adhere forms what is known by
the name of the bull's eye. The table thus made is, like the sheet,
placed in an annealing furnace, and there left for a proper length of
time.

The manufacture of _plate_ glass is altogether different from that of
crown and sheet. First of all, much greater care is taken in the
selection of the materials, the sand used being of a purer kind than
that employed in the manufacture of common window glass; the alkali is
of a better quality; and more caution is taken in all the manipulative
processes prior to the melting of the mixture. Arsenious acid is more
frequently used than manganese for the correction of the iron
impurity. It has been noticed that in the plate glass-pots, there are
grooves placed around their sides, and these are intended to receive
metal claspers, by means of which the pot can be removed bodily from
the furnace. In former times the glass was made in large pots, and
then ladled out into smaller ones, of a square form called _cuvettes_,
and in these it was left exposed to the heat of the furnace for a
length of time, in order that it might be refined, by the rising of
impurities to the surface and by the escape of air bubbles. The use of
these cuvettes is now discontinued, and the pot in which the glass is
founded is removed from the furnace and its contents poured upon the
tables on which the plate is formed, by the action of rollers. A plate
glass table is made of iron; its surface is smooth and of the size
required to make a large plate, and it is placed upon wheels and run
upon a tramway from one part of the glass-house to another, so as to
be opposite to the mouth of the furnace from which the glass-pot has
to be removed. Along the sides of this table, taken lengthways,
moveable strips of iron are placed, rising above it to a sufficient
height to secure the desired thickness for the glass plate, and on
these strips runs a roller, so adapted that it can be made to pass
pretty readily from one end of the table to the other. The contents of
the glass-pot, when placed over the table by means of a crane and
tilted up, fall out somewhat as a lump of dough would fall from a
kneading trough if it were inverted, for it must be borne in mind that
the glass in this process is not in a very fluid state. The roller is
made to pass rapidly over the softened glass, and in this way spreads
it over the table, until it comes in contact with the strips placed
along the edge, which serve as gauges for determining the thickness of
the plate. After the plate is formed, it immediately sets, and is
removed while hot into an annealing furnace, which is always so placed
that the glass can be transferred to it from the table with the least
possible delay. In this furnace several plates of fresh-made glass are
deposited, and are allowed to cool extremely slowly, in order that the
glass may be properly annealed. When this process is completed, the
plates are removed, the edges are trimmed off with a diamond, and one
plate, bedded in plaster of Paris, is placed upon a flat stone
receptacle; another plate, also coated on one of its sides with
plaster of Paris, is made to adhere to a piece of machinery placed
directly above the other plate, and is so situated, with respect to
this latter, that the two surfaces are perfectly parallel one to the
other.

It should be here mentioned, that the side of the plate which touches
the table is always rough, and has no polish, while that over which
the roller is passed is slightly undulating, and has a bright polish
similar to that of a sheet of blown glass, and which is technically
known as "fire" polish. The machine to which the upper plate is
attached is so arranged that, when set in motion, it causes it to move
in just the same direction that a plate would do if moved by the human
arm; this is therefore called an elbow motion. Boys stand by the sides
of the two plates, and throw fine sand and water on the lower one, so
that the opposed surfaces mutually grind one another, and when this
process is completed on one side, they are reversed, and the same
operation is performed on the other side. The plates have now the
appearance of ground glass, and the surfaces are further ground by
fine emery powder, which causes them to be much smoother and more
ready for the final polishing. Formerly this was entirely done by
hand, women generally being the operators, and oxide of iron, called
crocus, mixed with water, the material employed for polishing. Now,
however, a more rapid and perfect method is adopted by the use of
machinery. A table is prepared which moves from side to side, giving
to the plate a lateral motion; and above is a beam, in which holes are
drilled at intervals, through which short iron rods, nearly an inch in
diameter, pass. On these are padded iron buffers, covered on their
under surface with leather; while, pressing down these rods, and
therefore the buffers, are springs, which act with considerable force,
but which are able to yield to pressure caused by any inequality over
which the buffers may pass. The glass plate is fixed upon this table,
and its upper surface is exposed to the action of the buffers, while
oxide of iron, in a very fine state of division and mixed with water,
is allowed to come upon its surface. The glass travelling from side to
side is rubbed by the buffers in a lateral direction, and has also a
longitudinal motion, so that every portion of it is rubbed equally. If
any inequalities occur on the glass, the springs which press down the
buffers give way and allow them to rise over it, and this process is
continued for some time, until at last the plate receives the polish
so characteristic of plate glass. It is then removed from the table
and examined by skilled persons, and whatever defects can be removed
by hand, are remedied.

Another kind of plate glass, called "patent rolled plate," is made by
ladling out from a pot molten glass in the proper state of
consistence. The ladle is brought over a small glass table, and a
similar operation is performed to that already described. This patent
rolled plate is sometimes made with grooves on one of its surfaces, or
with patterns in imitation of diamond quarry glazing, and, in fact,
with any designs, according to the taste of the manufacturer. These
designs are all engraved upon the table, and communicate their
patterns to the soft glass; but the smooth surface of such glass which
comes in contact with the roller is slightly undulating, though
polished. This method of glass making was invented and patented by Mr.
Hartley, the noted manufacturer, of Sunderland.

A lighter kind of plate glass, which is principally used for glazing
the better class of pictures and engravings, and called "patent"
plate, is simply sheet glass polished after the manner of plate glass.
Crown glass, which only admits of being cut into small squares, is
also used for picture glazing, but is more carefully prepared, and is
called by the name of "flatted crown."

_Looking Glasses._--Plate glass is employed for making looking
glasses, and two processes are now in use for silvering them, the
first of which consists in applying a sheet of tinfoil saturated with
quicksilver to one side of the glass. The operation is conducted as
follows: on a perfectly smooth table a sheet of stout tinfoil is laid,
and on it is poured quicksilver, which is distributed evenly over the
surface with a hare's foot. When the whole sheet is amalgamated with
the quicksilver, more of that substance is poured over it, until it
flows quite freely. The glass plate to be silvered, having been made
perfectly clean, is floated upon the surface of the quicksilver, an
operation requiring care, and is then covered all over with weights,
by which means the excess of quicksilver is pressed out, and the glass
comes in contact with the amalgamated sheet of tinfoil, to which it
adheres entirely. This ancient method of silvering glass has some
advantages over the one next to be described. The colour of the plate
is, according to artistic taste, better, and with care the plate will
not lose its brilliancy for years. I have in my possession some old
glasses, the silvering of which is very beautiful, except where it has
suffered from mechanical injuries. Silver can be precipitated from a
solution of nitrate of silver in several ways, and in some of these
specimens was like a bright film. If a crystal of nitrate of silver be
put into a test-tube with some bitartrate of lime, and the mixture be
rendered ammoniacal and gently warmed (it being kept in motion during
the experiment), its sides will be covered with a very brilliant
deposit of metallic silver. Oil of cloves and grape sugar have also
the power of reducing metallic silver from ammoniacal solutions of the
nitrate, when gently warmed; but the mixtures must not be made too
hot. In silvering plates of glass, they are first well cleaned, then
placed in a perfectly level position, and the silvering liquid is
poured over the surface, the room in which the operation is performed
being kept sufficiently warm to assist the deposition. When enough
silver has been deposited on the glass, the liquid is poured off and
the plate dried, while the silver film is protected by being coated
with a suitable hard varnish. The composition of the mixtures used by
different persons is generally kept secret, though the chemical
principle of the reduction of the silver salt is the same. Glasses
silvered by this process sometimes lose their brilliancy, by becoming
covered on their silvered side with small spots. It is however stated
that this results either from a bad system of deposition, or from the
film of silver not being sufficiently thick and solid.

_Flint Glass_, although called by this name, is not made from flint,
but from the best sand, of pure and dazzling whiteness, obtained from
Alum Bay, in the Isle of Wight, and from Fontainebleau, in France. The
cost per ton is from 1_l._ to 1_l._ 15_s._, whereas the price of
the sand used for making plate glass is about one-eighth of that
amount. The alkali employed is generally extremely good carbonate of
potash, whereas soda is used in the manufacture of the other kinds of
glass which have been described. The addition of a small quantity of
black oxide of manganese is sometimes necessary to correct the slight
tint imparted by iron, which seems to be always present in minute
quantities, even in the purest samples of sand. Oxide of lead in the
form of red lead, in this sort of glass, takes the place of lime. The
advantages derived from using the oxide are, that it makes the mixture
more fusible, and also imparts that particular brilliancy and lustre
so peculiarly characteristic of well-made flint glass. In different
works, various mixtures are made for the composition of the glass; but
to give an idea of the proportions in which the materials are mixed,
it will be well to quote the statement of M. Payen, who says that of
the finest crystal flint glass, the following is the composition:
sand, 3; red lead 2 to 2-1/4; carbonate of potash, 1-1/2 to 1-2/3. A
little nitre or saltpetre is used as an oxidizing agent. The
glass-pots employed in this branch of the manufacture are covered, so
that the flames of the furnace do not come in contact with the
materials, the object in thus isolating them from direct contact with
the flame being to prevent the entrance of impurities, by which the
colour might be injured. On account of the pots being covered, the
materials take a much longer time to get hot, and require quite double
the time in founding that sheet or plate glass does; the presence of
oxide of lead materially assisting the rapidity of the fusion. When
flint glass is ready for working, the time required to work off a pot
of it is much longer than that which is required for a pot of crown or
sheet; and it is a matter of considerable importance, that the
furnace-man should so manage his fires as to keep the glass in a
proper working condition, that is, he should not let it get too cold
(therefore too solid) nor too fluid. Flint glass is worked off by the
blower into wine-glasses, tumblers, decanters, and other suitable
vessels. Let us take a wine-glass as an illustration of the method of
working. A small quantity of glass is gathered on the blowpipe, which
is much smaller than that used in making sheet, and is blown into a
bulb, which may be slightly elongated or globular, the forms being
given to it by the motion which the workman imparts to his blowpipe
while he is blowing, or after he has blown, into the mass. In the case
of a wine-glass, an assistant boy gathers a small quantity of glass on
the end of a small pointel, or solid iron rod. This is placed on the
side of the globe opposite that which is in connection with the
blowpipe, which is then detached by touching the glass nearest it with
a piece of iron, wetted with cold water: this causes a crack, and a
gentle tap causes separation. The workman then moulds the opening made
by detaching the blowpipe, in order to do which, he has to apply the
glass often to the mouth of the furnace, to soften it. He then opens
out the globe into the shape of a cup with a pair of small iron tongs,
with legs uniform in shape, slightly tapering and smooth, and he uses
a peculiar kind of scissors for trimming the edges. The other parts of
the glass are moulded with the tongs, accuracy of size being obtained
by means of measuring compasses and a scale. The workman sits during
this operation in a seat with arms, laying the pontee on them, and
turning it, so as to make it move backwards and forwards with his left
hand, while with the tongs in his right he gives the glass the desired
form.

Before passing on to a description of the manufacture and composition
of coloured glasses, it is necessary that I should make a few remarks
on the difficulties under which our English glass makers labour, owing
to not paying sufficient attention to the scientific treatment of
their mixtures. It has already been stated that glass is composed of a
mixture of silicates, which are definite chemical compounds. Some are
much more dense than others, and are therefore liable to sink, so that
the glass taken from one part of the pot will be very different in
composition from that taken from another part; besides this, it is
found on examination, that other portions of the materials employed
are present in such proportions, that they cannot possibly exist in
the form of true silicates. M. Dumas, the distinguished French
chemist, asserts, and with truth, that glass ought to be a true
chemical compound. This, however, does not seem to be the opinion
here; and sufficient attention is not paid by English manufacturers to
mixing their materials, so as to form definite silicates, the result
being that glass is produced with a striated effect. This is easy to
be seen in the common kinds, as in bottle glass; but owing to the more
careful and prolonged fusion of the finer varieties, such as plate
glass, this defect is to a considerable extent remedied, though not
altogether overcome. In the French manufacture of plate glass, more
attention has been paid to the chemical composition of the various
silicates which enter into it. At St. Gobain, a plate glass, is
produced which, on analysis, is found to contain definite silicates,
and without any excess of material which does not enter into chemical
combination; and the consequence is, that this glass is more perfect
and homogeneous than that made in this country. No doubt this superior
quality is owing to the fact, that the famous chemist, Gay-Lussac,
devoted much of his time to assisting in the manufacture carried on at
these works. We cannot over-estimate the importance of a scientific
superintendence, not only of glass-works, but of all other
manufactures in which chemical reactions take place; for although
experience may lead a cautious observer to produce substances of
nearly correct composition, yet the assistance of a scientific
observer is of the greatest importance, because, what under other
circumstances must be simply empirical, is under his guidance carried
on according to definite and fixed laws.

Mention has already been made of how, in the case of mixing carbonates
of soda and potash, the one assists the fusibility of the other, and
this is more particularly true in the mixture of silicates in the
composition of the ordinary glass. Silicates of soda and potash are
separately much more infusible than a mixture of the two, and the
addition of other silicates to them renders them more fusible still;
silicate of lead, as has already been mentioned, causing the glass
into whose composition it enters to fuse at a much lower temperature
than it would do if that silicate were absent. Again, if the silicate
of lead be present in too large proportions, and if great care be not
taken in the manufacture of lead glass, the silicate of lead, from its
greater density, will sink lower among the molten silicates, and will
therefore cause a larger proportion of lead to be in the glass at the
bottom of the pot than there is at the top. We often notice in
tumblers and decanters of the cheaper kind, that there are very
distinct striÃ¦ running through the whole substance in some particular
portion of the glass. Now this is owing to the greater density of the
lead silicate, which sinks lower down in the collected mass of glass,
and therefore imparts to it this peculiar effect. When a pot of flint
glass is worked off, that which remains at the bottom usually contains
more lead than that which is worked off in the earlier part of the
day.

_Coloured Glasses._--It has been before shown that silica unites with
metallic oxides; in fact, glass is nothing but a compound brought
about by the union. With certain metallic oxides, silica forms
coloured silicates or glasses; and these, when fused with colourless
glasses, impart to them the colour of the silicate. Oxide of iron
colours glass either green or yellow, according to the nature of the
oxide; the silicate of the protoxide of iron being green, and that of
the peroxide, yellow of a slightly brownish tint. Copper forms two
oxides, the suboxide and the protoxide; the suboxide colours glass
red, while the protoxide renders it green. Black oxide of manganese
colours glass purple; but if large quantities be used, it makes it
perfectly black. Sesquioxide of chromium imparts a beautiful green
colour to glass, while oxide of uranium produces an opalescent effect
of yellow with a tinge of green. This latter, by the way, has the
power of reducing the ultra-violet rays of the spectrum to luminous
rays, and, when held in the rays of a spectrum obtained by the
electric light, produces an extremely beautiful effect, which is
called fluorescence. A small quantity of the oxide of gold tints glass
pink, but the colour becomes extremely rich and ruby-like, when a
larger quantity of the oxide is employed. Oxide of cobalt in very
small quantities yields, with silicic acid, an intensely blue
silicate. This substance, carefully prepared in a special manner and
ground to a fine powder, forms the well known water-colour pigment
called smalt. Oxide of silver stains glass from a delicate lemon tint
to a deep orange, in proportion to the quantity of the oxide employed.

With the exception of the last-named colouring material, the above
mentioned are mixed together with the substances which form the glass,
and are melted in the usual way in glass-pots, except that they are
treated with considerably more care, in order that their tints may be
true. Oxide of silver, however, is never mixed with the materials of
which the glass is made, but is applied to the surface in the
following manner: a solution of nitrate of silver mixed with some
substance, such, for instance, as chalk, may be painted upon the parts
of the glass which it is desired to stain, and these are heated to a
dull red heat, in what is called a "muffle." Wherever the oxide of
silver, which is reduced from the nitrate by heat, comes in contact
with the glass, the latter is stained more or less intensely,
according to the quantity of silver present. Pure metallic silver may
be melted with metallic antimony, and the mass ground to a fine powder
in water. This powder, after being mixed with some Venetian red and
gum water, is applied to the surface of the glass, which is, when dry,
heated to a dull red heat in a muffle, producing the yellow stain,
which can be seen after the Venetian red and the excess of silver have
been scraped off. The reason why silver, or oxide of silver, is not
mixed with the glass materials and fused with them, is because it does
not readily unite with oxygen, and, when it has done so, it loses its
oxygen again at a high temperature, and becomes reduced to the
metallic state; and inasmuch as metals have no effect whatever in
staining silicates, glass made in this way would not have the yellow
colour which it has, when the silver is heated upon its surface to a
much lower temperature in a muffle; for the temperature to which the
constituents of the glass must be heated, so as to cause them to burn
it in, would be so high, that the oxide of silver first formed at a
lower temperature would be reduced to the reguline or metallic state.
Gold also, like silver, does not unite with oxygen readily, or remain
in union with it at high temperature; therefore great care is required
in the preparation of glass to be coloured by oxide of gold; the form
in which it is used being generally that of the purple of Cassius,
made by precipitating a salt of tin with a salt of gold. This
substance is mixed with the glass to be coloured, and heated in a
suitable glass-pot. Portions of it are gathered and allowed to cool,
these being generally of a yellowish, brownish, and sometimes reddish
tint, though they have not in any case the same beautiful red colour
which they produce when applied, as will be immediately described, to
the surface of white glass. A certain quantity of white glass is
gathered from the glass-pot in the soft state with one of these pieces
of gold glass; the whole mass is heated until both become soft, and is
then blown and formed into sheet, which, on examination, will be found
to consist mainly of white glass, with its surface thinly covered with
the glass stained with oxide of gold, while the beautiful ruby colour,
which the gold imparts to the glass, appears pure and distinct. If
such glass as this be heated to too high a temperature, as when it is
used in the manufacture of stained glass windows, the ruby colour is
in part, and sometimes altogether, destroyed, for the oxide of gold
loses its oxygen, and metallic gold is left behind, which does not
yield a colour to the silicate. I have in my possession a piece of
French glass of a pale sapphire tint, which, when heated in the
oxidizing flame of the blowpipe, assumes a brilliant and intense ruby
colour, showing that in the first condition, the gold is not in a
state of oxidation sufficient to impart colour to the glass.

When the suboxide of copper is mixed and fused with the glass which it
is intended to colour, the result is an opaque substance, almost like
red bottle-sealing-wax, which is treated in a manner exactly similar
to the gold glass; viz. it is coated with white glass, and blown and
shaped into sheets, which owe their intense ruby colour to a thin film
of the coloured glass closely adhering to the mass of the white upon
which it is placed. Glass made in this way is called "coated," and
sometimes "flashed" glass, and is extremely useful for ornamental
purposes, for by the action upon the coloured surface of hydrofluoric
acid, the ruby coating can be eaten away, and the white glass beneath
left entire. If the backgrounds of the patterns be painted upon the
ruby side with a material like Brunswick black, which is able to
resist the action of hydrofluoric acid, and if the plate of glass, on
its ruby side, be exposed to the action of the vapour of this acid, or
to the action of the acid in solution in water, in a short space of
time the pattern will be eaten away; and if the Brunswick black
coating be removed with turpentine, a sheet of ruby glass will be
obtained with a white pattern etched upon it.

Owing to the powerful colouring properties which oxide of cobalt
exerts, a very deep-coloured blue glass can be made, which can be
treated like the red copper glass, and may be made to coat and cover
in the same way the surface of plates of white glass. Purple glass,
coloured with oxide of manganese, and green glass are also sometimes
used as coating materials for white glass, but other colours are never
employed in this way.

It is manifest that if different metallic oxides be used with the same
glass, mixed tints will be produced, so that by mingling small
quantities of oxide of cobalt and protoxide of copper, a blue glass
having a greenish hue may be obtained. The revival of glass painting
has caused manufacturers to turn their attention to these mixtures, in
order to produce tints resembling those of ancient stained glass.
Messrs. Powell and Son, of Whitefriars, were the first to perform
experiments on these mixtures, and after much laborious attention and
patience their efforts have been crowned with great success, for they
have been enabled to produce glass as beautiful in tint and in texture
as the best specimens of ancient manufacture. Their example has been
followed by others, such as Messrs. Hartley of Sunderland, and Messrs.
Chance and Co. of Birmingham.

While treating of the effect produced by different metallic oxides
upon colour, it may be well to mention that the opaque glasses used
for such purposes, as the enamelling of watch-faces, are made by
mixing with the materials a certain quantity of arsenious acid (or
white arsenic), in much larger quantities than when it is employed
simply to correct the tint imparted to glass by the iron impurities in
the sand. Oxide of tin also renders glass white and opaque, and a
certain quantity of bone ash will produce a similar effect, though not
in so satisfactory a manner.

_Glass painting_ first became general in this country at the time
when the Early English style of architecture prevailed, and some of
the best specimens were executed during that period. By the best
specimens is not meant, that the figures painted upon those windows
were artistically as correct as similar works of a later date, but
that they were designed and executed in accordance with those
principles, which should always govern the adaptation of a substance
like glass to ornamental purposes. The earlier mediÃ¦val artists
depended for effect more upon the boldness of their outline, than upon
the intensity of their shading or the delicacy of their manipulation.
The form of a thirteenth-century figure is merely indicated by a few
bold and well drawn outlines, the features being formed by lines, the
pupils of the eyes by simple well-shaped masses of opaque pigment; and
such a treatment as this was quite sufficient to convey what was, to
the observer, more or less a symbolical, than a truthful
representation of the Scripture history which they were intended to
illustrate. These artists remembered that windows are openings in a
building, through which light has to pass, and they did not,
therefore, like many of the later imitators, render them opaque by
masses of intense shadow, which perfectly obscure the colour of the
glass upon which the picture is painted, and render the passage of
light through it simply impossible. The thirteenth-century glass
painters, too, in the treatment of their shadows, bore this great
principle in mind, and instead of daubing and stippling them on,
usually indicated them with a thin wash of enamel colour, intensified
in parts by lines crossing one another, and therefore called
cross-hatching, through the interstices of which the light, although
subdued, was able, in a measure, to pass.

But as the object of this article is not to discuss the merits of the
various styles of glass painting, however much I might desire to
enlarge upon it, I pass on to a description of the methods employed in
the manufacture of stained glass windows. In the first place, after a
design has been drawn, in which the effect of the window as a whole
can be carefully considered, cartoons of the figures and ornament are
made of the exact size of the intended painting. And here it should be
noted, that all the lines should be extremely clear, precise, and well
drawn, because it is from these that the workman, who is not usually
himself an artist, has to convey on the glass the feeling of the
artist. The cartoon, when completed, is laid down in pieces for
convenience-sake on a table, and fastened with small nails. The
glass-cutter then selects the various coloured glasses which are
required to be inserted in their proper places, so as to carry out the
design of the artist. For instance, a piece of white or yellow-tinted
glass is cut to the shape of the face. If the figure be a small one,
the hair also is included in this; and probably in the figure of a
saint, the nimbus which surrounds the head may be included; while in
larger figures, particularly in the earliest styles, the face was of
glass of one tint, the hair of another, and the nimbus of one or more
tints, different from either of these. Sometimes, in the later styles,
the hair, after the face was painted and burnt in, was stained with
the silver stain already described, so that when the glass was
cleaned, it was of a yellow colour. However, not to enlarge more upon
these points, which really belong more to the artistic than to the
industrial part of window painting, let us proceed to the
consideration of manipulative details. The outlines of the figures and
ornament are painted with a substance called "tracing brown," made by
mixing with a flux some oxide of iron, heating them together in a
crucible and grinding the product to a fine powder, which is mixed
with certain vehicles adapted to the particular use to which it is to
be applied. Different fluxes are employed by different glass painters;
some contain borax, because such fluxes fuse more easily, and
therefore cause the glass which is painted to be exposed for a less
time, and to a lower temperature, than when less fusible fluxes are
used.

It is always satisfactory to an author, to feel that his articles have
been of some use to those whom he hoped to benefit. Since this article
was written a letter appeared in one of the architectural journals,
complaining that the glass furnished by manufacturers to glass
painters was of inferior composition to that which was used by the
manufacturers of ancient stained glass windows. In fact, it was
asserted that modern glass was not made with due care, and that to
this was owing the unfortunate disappearance of some of the painting
and tracing of modern stained glass windows; but that this is not the
case, is manifest to all who understand the manufacture of glass. The
real reason why the colouring matter with which glass painters outline
and shade their designs, has in many instances gradually come off from
the surface of the glass, is, because the fluxes used for making it
adhere to the glass are of such a composition, that they themselves
have by the action of time become disintegrated.

Some time ago, a person engaged in the manufacture of the enamel
plates used for railway lamps, on which are written the names of the
stations, called upon me, and told me, that the enamel which he
employed had become dark, spotty, and in many cases had peeled off
from the glass. The reason of this is identical with that which occurs
in stained glass windows, viz. that the fluxes that he used were not
suitable for the purpose, considering that they had to withstand the
action of the weather. From an analysis made of these fluxes (not of
those last alluded to, but of those which have been employed in
stained glass windows), it appears that large quantities of borax have
been introduced; and, wherever this is the case, no reliance whatever
can be placed on the permanency of pictures painted with such fluxes.
I have appended a few receipts for fluxes, which can be used with
safety by any glass painter who will take the trouble to try them. But
I must strongly advise that all those who are connected with the
making of fluxes in any glass painting establishment, should master
sufficient chemical knowledge to enable them to ascertain the
behaviour of the materials, with respect to one another, as well as of
the nature of the glass upon which they are employed; for very much
indeed depends upon a correct knowledge of the character of the glass
as to whether it be hard or soft, what it contains, and of the
temperature at which the glass becomes sufficiently soft to form a
firm and enduring union with the colours fluxed upon it.

  RECEIPTS FOR FLUXES.

  1.
  Flint glass (powdered)      10 parts. } moderately
  White Arsenic                1   "    }   hard.
  Nitre                        1   "    }

  2.
  Red Lead                     1   "    }   soft.
  Flint glass (powdered)       3   "    }

  3.
  Flint glass                  6   "
  Red Lead                     8   "
    (Mixed with four parts of the first flux, soft.)

The use of very soft fluxes is attended with this inconvenience, that
the boracic acid contained in them is generally acted upon by moisture
and becomes hydrated, and in this condition often causes the painting
to peel away. Harder fluxes, although they have the disadvantage of
necessitating the glass to be submitted to a much higher temperature
for a longer time in the kiln or muffle, are the best, and, with
judicious management, can be used without any injurious consequences
to the work on which they are employed. Lead fluxes, containing oxide
of lead, are sufficiently fusible for all ordinary purposes, and are
not liable to the same objection as fluxes containing borax. Suppose,
then, it is desired to paint the outlines of a face, the glass is cut
to the shape of the face in the cartoon; it is then laid upon it, and
the painter, seeing the lines through the glass, is able to trace them
with his brown paint upon its surface. He generally uses gum water as
his vehicle, and puts on the shading also with the same mixture,
though sometimes it is found necessary to use a substance which is not
affected by moisture, as for instance, tar-oil. It is impossible, in
the short space of this article, to indicate those occasions on which
one should be used in place of the other; a knowledge of this can only
be obtained by consulting authorities in which details are more
minutely given, or by watching the operations of the glass painter in
his workshop. When the face is finished, it is removed, and another
portion of the figure, say a piece of the drapery, is proceeded with
in exactly the same way; and so, by a repetition of this process in
all parts of the figure, it is completed, and looks very much like a
puzzle, the parts being put together on the cartoon before the work is
finished, in order to see that the whole is harmoniously treated. In
shading the face, hands, and those parts of the drapery which require
it, a glass easel is used, on which the figure is put together, and
the parts made to adhere by wax, so that the artist is able, while
painting, to form an idea by transmitted light of the effect which
will be produced when the window is finished. The ornament is painted
in a similar manner, but usually not with the same care in the details
of its execution.

When all the glass is painted, it is fired in a muffle, upon the
proper construction of which a great deal depends. It is usually made
of iron, and should not be more than 15 inches from its bottom to the
top, though its width may vary. It is never well to have muffles for
firing glass for painted windows larger than about 2 feet wide, by 2
feet 6 inches deep. The top of the muffle is usually slightly arched
from side to side, and it is placed in the furnace on a tolerably
thick stone floor, so that the bottom may not get too hot. The fire,
which is lighted below, is allowed to play up its sides and over its
top, the flue being so built as to draw the flames in that direction,
for a top heat is the best heat for firing glass regularly. The muffle
is arranged with ridges in its sides, passing from front to back
parallel to one another on one side, and exactly opposite to
corresponding ridges parallel to one another on the opposite side.
These metal ridges are intended to receive iron plates, and there is
generally about an inch or rather less between the top of one plate
and the bottom of another, when the muffle is perfectly filled. The
plates are covered over with perfectly dry powdered chalk or whiting,
and the pieces of glass are laid upon them with their painted sides
uppermost. When the plates are charged, they are put into a muffle
with an iron door, in the centre of which is a hole, and a conical
tube with the base attached round it. It is larger than the opening at
the other end, which projects some 6 or 7 inches from the surface of
the muffle-door at right angles to it. A second door is then placed at
a short distance from the first, the tube passing through a hole made
for the purpose in it. The orifice is usually stopped by a piece of
fire-clay, which can be removed at pleasure. The use of the tube is,
to enable the manager of the kiln to look into the muffle, from time
to time, to see that the glass does not get too much heated. When the
firing is completed, the fire is raked out and the muffle is allowed
to cool very slowly, and by this process the glass becomes annealed.

When it is desired to apply to any portion of white glass some yellow
silver stain, this can be done either in the first firing, by floating
it on to the places to be stained, and allowing it to run in a sort of
stream from the brush, so that it will evenly cover the surface and
cause the heavier portions of the stain, namely, the mixed metallic
silver and antimony, to sink regularly to the bottom, and come fairly
in contact with the glass. Not very long ago, it was mentioned to me
by a glass painter of note, that the workmen much prefer using the old
stain made with silver and antimony, to that which is produced by
using nitrate of silver. This really is a mistake on their part, for,
when properly managed (and the knowledge of how to manage this stain
can be acquired with very little trouble), the nitrate of silver stain
is by far the best, and produces much better tints, with less chance
of what the men call sulphuring when the glass is fired. This
sulphuring is simply the result of opacity, obtained by heating the
glass to too high a temperature. If the staining is to be performed in
the same firing as that by which the painting is to be fixed, it is
quite clear that the outlines of the part to be stained must be
painted in, with tar-oil, or with some such substance which is not
affected by the moisture of the stain. However, in general, the
staining operation is performed after the first firing, that is to
say, those pieces of glass to which the silver is to be applied are
stained in the method above described after the first firing, and are
then fired again, because the heat required to produce a good stain
from silver is of a somewhat different character from that which is
required simply to fuse the flux that binds the pigment to the glass.
A longer and less intense heat, technically called a "soaking," is the
best for producing an even and pure yellow tint. If the temperature be
allowed to rise too high, the oxide of silver, which alone can stain
the glass, gets reduced wholly or in part, and when this happens to
only a slight extent, it destroys the transparency of the stain; and
when it happens to a great extent, it destroys its colour altogether,
making the glass opaque.

It is a matter of astonishment to me that glass painters do not use a
ruby stain, which, with a little practice, can be managed quite as
successfully as the yellow silver one. It is true that it would be
impossible to fire the ruby and the silver stains together, and it
would not be at all convenient to fire the ruby stain at the first
firing of the painted glass. The method of staining ruby is as
follows: grind up carefully some black oxide of copper, mix it with
water (or with a small quantity of gum added), float it on the parts
to be coloured, place it in a kiln and heat it. Black oxide of copper,
when mixed with glass and melted in a glass-pot, makes the glass
green; suboxide of copper, which contains less oxygen than the black
oxide, when treated in the same way, makes it red. Now, if it can be
reduced to the lower oxide of copper, while the black oxide of copper
on the surface of the glass is heated, it will then colour the glass
red. The best way of reducing the black oxide, is to connect the
muffle with a gas-supply pipe, and allow coal gas to pass during the
whole time that the heating process goes on. The action of the gas,
which contains hydrogen and carbon, is to take away oxygen from the
black oxide of copper, when it is at a high temperature; and, as soon
as sufficient is taken away by the hydrogen to reduce the black oxide
to the state of suboxide, it stains the glass red. It does not matter
if the reducing action be continued longer, so that the oxide of
copper be reduced to the metallic state; for at that temperature, the
stain produced by the red oxide of copper is not removed by the
continued action of hydrogen gas. The employment of this process would
certainly enable artists who paint in the later styles of glass
painting, to very much enrich their draperies, and to produce, more
easily, effects which now can only be obtained by a complicated system
of lead-work.

When the pieces of glass which have been fired are perfectly cold, the
next process is to unite them altogether by peculiarly shaped strips
of lead, which are of various kinds, according to the character of the
subject required. The lead has a thick part or core, and at right
angles to the top and bottom of this are thin plates called the
"leaves." The core is milled with little ridges running at right
angles to them, so as to enable the workman to bend the lead about
with facility. The edges of the piece of glass to be leaded are placed
between the leaves and resting upon the core, and the lead is thus
arranged all round the glass, and is then laid in its proper situation
upon another cartoon, prepared from the one from which the figure was
painted, and indicating simply, by lines, where the lead-work is to
come. The first piece is fixed by means of nails temporarily placed
through the lead. Those pieces which touch it in the design are put in
their proper positions, so that the edge touching the next piece will
be underneath the opposite leaves to those which confine the first.
This operation is repeated, till all the parts of the design are
surrounded by lead, and by it united to one another; the joints being
secured by solder, generally applied by gas. Nothing now remains but
to fill in the interstices between the lead and the glass, so as to
make the window firm, solid, and water-tight; and this is done by
rubbing into them with a scrubbing brush a cement, usually made of
white lead, oil, and plaster of Paris. This composition varies in
different stained glass works, nor is it material, provided that the
substance hardens, does not crack, and is waterproof.

From this description it will be seen, that the various colours in the
different parts of the window are put in as pieces, and that no
colours, properly so called, are applied by the brush to the surface.
There are, however, certain tints of the "tracing brown," which can be
obtained by the addition of black oxide of manganese, or by a
different method of preparation of the oxide of iron, to give it its
body. Sulphate of iron, when heated, loses its sulphuric acid, and the
oxide, which was, as sulphate, in the state of protoxide, becomes, by
heating, the red or peroxide of iron; its tint, when made in this way,
being generally lighter than the tint of that form of oxide which is
employed as ordinary tracing brown. It is sometimes called flesh tint,
though this is decidedly an objectionable name for it.

It has been suggested to me, that I should give some receipts for the
manufacture of the enamel colours used in mediÃ¦val glass painting; I
have therefore added a few which are easily prepared. Others of a more
complicated nature had much better be obtained from the makers of the
enamel used in porcelain painting. And here again, let me remark, that
in ordering fluxes from these manufacturers, it should be stated
especially that a flux is required which does not contain borax, nor
should the painters in any establishment be allowed to use these
softer fluxes, which they are almost certain to do, unless forbidden;
for though they are easier to work with, they will infallibly lead to
calamitous results.

  YELLOW.

  Oxide of tin                           2 parts.
  Oxide of antimony                      2   "
  Red Lead                              16   "

  ORANGE.

  Red Lead                              12   "
  Oxide of antimony                      4   "
  Persulphate of iron                    1   "
  Flint powder                           3   "

  BROWN.

  Black oxide of manganese              2Â·25 "
  Flint slate (powdered)                4Â·0  "
  Red lead                              8Â·5  "

  BROWN RED.

  Crocus (oxide of iron)                 3   "
  Green sulphate of iron (calcined)      1   "
    mixed with six parts of these No. 2.

  LIGHT RED FOR FLESH TINTS.

  Carbonate of lead                      1Â·5 "
  Persulphate of iron (calcined)         1   "
  Flint glass                            3   "

The use of enamels--that is, substances which impart various colours
to the glass, when placed on its surface by their fusion--is not
admissible in windows which pretend to belong to any of the earlier
styles of glass painting; though enamel painting is used for the
decoration of houses, and sometimes, as I consider very improperly,
for the decoration of church windows. One sheet of glass, colourless
and transparent, or it may have its surface ground, is usually
employed. A subject is painted on it with enamel colours, much as
subjects are painted upon porcelain. When the work is completed, the
glass plate is fired, and thus the colours become semi-transparent,
and perfectly adherent to the plate; but they are not clear and
bright, and transparent, as are the colours of glass which is coloured
in the pot, and therefore have not the same brilliancy, nor do they
allow of the same bold and effective treatment.

It is much to be desired that amateurs who can draw, and who have a
feeling for this particular style of art, should devote a portion of
their time to its execution. They will find it to be extremely
agreeable and pleasant, and the few difficulties which they meet with
in their first attempts will be readily overcome by perseverance, or
by applying for assistance and advice to gentlemen engaged in the
pursuit of this interesting profession.

_Moulded and Cut Glass._--Flint glass is now very commonly blown
in moulds, and this art has been brought to such perfection that
moulded decanters and tumblers have an appearance very similar to that
of cut glass. The moulds are always made of metal, and so constructed,
that they open out into two or more pieces, which are generally hinged
to the bottom of the mould. The workman places it on the ground, and
fixes it by standing on projections from its side. He then gathers a
suitable quantity of glass on the end of his blowpipe, which he places
in the mould, and the side of the glass touching it will thus have
impressed upon it whatever form is engraved on it. After the glass has
become hard, the mould is opened, and the glass vessel is removed and
annealed.

When it is desired to cut a design on the outside of a tumbler or
wine-glass, the vessel is, in the first instance, blown of a thicker
substance than if it is to be left uncut. The necessary shapes, which
are usually in facets, are cut upon it by the action of sand and
water, a lathe of a very simple construction being used to give a
rotary motion to cutting discs, made of stone and kept continually
moist by water dripping on them, so that when the glass is pressed
against them, the required portion of its surface is worn away. The
usual diameter of these stones is about 10 inches. After the rougher
stone has been used, a finer kind of sandstone disc is employed, or a
disc of slate, upon which sand and water are allowed to drop, and the
already roughly cut surface is, by their action, partly polished.
Copper discs with flattened circumference are used for polishing the
glass, and for this purpose, emery mixed with oil, is applied to the
edges of their circumference.

_Ground Glass_ is made by rubbing the surface of glass with sand
and water, just as in the first operation of plate glass polishing.
But a very ingenious method is now generally adopted for grinding
glass, by placing it in a cradle, so that it can swing from side to
side; sand and water are placed upon the glass, and it grinds itself,
so to speak, by this operation.

_Annealing and Devitrification._--As the word "annealing" has been
often used in this article, it will be well to explain what is its
action. If a piece of molten glass be dropped into water, it will
assume an oblong shape, the lower end of which will be round, while
the other will taper off into a fine point. These drops, which have
received the name of Prince Rupert's drops, look like pieces of
ordinary glass, and if the small end of one of them be broken off, a
sort of explosion takes place, and the whole mass flies into a
thousand minute pieces, some of which will be found to have been
driven to a considerable distance. Here then it appears, that when the
skin, which is perfect and entire in the Rupert drop, is broken, the
bond which held together the constituent particles is broken also, and
so they are acted on by a repellent force, and fly away from one
another. If hot water be poured into a thick common tumbler, it very
generally cracks it: but if the tumbler be thin and of better
manufacture, it will bear almost boiling water without cracking. In
the first case it has been badly annealed; and besides this, glass
being a bad conductor of heat, from its thickness, the heat imparted
by the hot water expands the inner surface, while the outer coating,
not being warmed, does not expand, and, retaining its original form,
is burst. If, however, a tumbler be thick and properly annealed, there
is not so much danger of its breaking, when a portion of it is exposed
to a considerable rise of temperature. In the case of the Rupert
drops, they are not annealed at all, and so there is no cohesive bond
between the particles, such as there would be if they were properly
annealed, that is, if, instead of being cooled suddenly from the
molten state, they were allowed to cool in a heated chamber very
slowly. After glass has been heated, the particles of which it is
composed take a long time to rearrange themselves, so that in the
manufacture of thermometers, it is necessary, after sealing up the
bulb and tube which contain the mercury, to allow them to remain for a
long time; otherwise the pressure of the air on the outside of the
bulb, not being supported by any air on the inside, causes the
particles of glass to become more compact, and thus renders the
capacity of the thermometer bulb and tube smaller than it was, when
the thermometer was first sealed. It seems that the process of
annealing glass gives time for the particles to arrange themselves in
such a way, that when the glass is cold, it will not be so liable to
fracture from sudden changes of temperature.

Considerable curiosity has been excited of late by a new invention,
which has resulted from the investigations of a Frenchman. We have
been told that tumblers and wine-glasses, and other glass utensils,
could be so treated that they would never break; and experiments
performed upon many samples of these glasses led one to suppose, that
the object had been attained. There is no doubt whatever, that some
who have had experience of what is termed toughened glass know, that
in many cases very uncertain results are obtained in the resisting
power of the glass to the action of a violent blow. Before, however,
entering into some researches which I have made on the subject, it
will be well to state what is the nature of the change which the
toughening process produces in the glass, and this seems to be a fit
place for this consideration, as the method of making, and the
behaviour, of Prince Rupert's drops, have just been discussed.

The physical properties of these Rupert's drops have been examined
with great care by M. Victor de Luynes, and the results of his
experiments have been communicated to the _SociÃ©tÃ© de Secours des
Amis des Sciences_. For the purposes of this article, many of
his experiments have been repeated, confirming in general his
observations, and others have also been instituted. The toughness and
hardness of these drops are remarkable; the thick pear-shaped portion
will bear a sharp stroke with a hammer without breaking; nor can it be
scratched with a diamond. To break the tapering thread or tail, as it
may be conveniently called, requires considerable force. To find out
what weight was required to do this, a series of experiments was
performed, the results of which are given in the table following. The
tail of a drop was placed over a small hole bored in the top of a
table; a hook was then adjusted round a part of the tail which
measured 19 on a Birmingham wire gauge; below the table and attached
to this hook, a scale-pan was hung. This pan was then carefully
loaded, all shock being avoided, until the thread was ruptured and the
weight required to effect this was then noted:

  White Glass Rupert's Drops.

  Gauge.              Strain.
    19            16     lb.  0 oz.
    19            15-1/2  "   0  "
    19            16      "   0  "
    19 (poor)      9-1/4  "   0  "

  Green Glass.

  Gauge.               Strain.
    19            18-3/4  "   0  "
    19 (poor)      9      "   0  "
    19            28      "   6  "
    16            26-1/4  "   0  "

It will be observed that the drops made from green bottle glass
withstood a greater strain than those made from crown glass; the
latter, in fact, did not break throughout their mass, but left a
portion of the bulb unbroken, showing some fault in the tempering. It
was with difficulty that the workmen could be induced to make drops
out of this kind of glass, as they knew by experience that they
usually failed to break perfectly, and they stated that it was quite
impossible to make them with lead glass. To ascertain what force was
required to fracture a thread of like dimensions that had not been
tempered, one of the drops was heated to redness, and annealed by
allowing it to cool very gradually. When subjected to the same trial,
it was fractured by a weight of 12 ozs., and the drop did not break
into small fragments, but behaved exactly like ordinary glass, thus
showing that the glass had been _un_tempered by the heating process. A
piece of glass rod, drawn out into a thread in a gas flame, when
subjected to the same conditions, bore a strain of 10 oz. A
sewing-needle of the same thickness was broken by a weight of 3 lb. 14
oz., thus showing that the tail of the Rupert's drop was very much
tougher than tempered steel. By suspending a Rupert's drop in such a
manner as to allow the tail to dip into hydrofluoric acid, it is
found, that when the surface or skin is eaten away to a certain depth,
rupture takes place exactly in the same manner as when the tail is
broken. In whatever way fractured, the particles, when examined by the
microscope, show a crystalline structure, and do not at all resemble
pieces of ordinary glass; when rubbed between the palms of the hands,
they do not cut, nor scratch, nor penetrate the cuticle. If a drop be
enclosed in plaster of Paris so as to leave a portion of the tail
exposed, it may then be broken and all the particles will remain _in
situ_. On removing the plaster, it will be found that the drop has
been broken up into thousands of minute needle-shaped particles
arranged in cones, the apices being in the direction of the tail. It
would appear then from these experiments, and from observations with
polarized light, that the glass in the interior of a Rupert's drop
exists under enormous tension, and that it is only prevented from
bursting into fragments by the outer skin; on its being broken in any
part, the bond which holds together the constituent particles is
broken also, and so, being acted upon by a repellent force, they fly
away from one another. There is another kind of toy resembling in some
respects the Rupert's drop, known as the Bologna bottle or
philosopher's flask. It has the form of a soda-water bottle with the
neck cut off, the bottom being rounded off and very much thicker than
the walls. These flasks are sometimes formed accidentally in
glass-works by the workman, who, in order to examine the quality of
the glass, takes out a portion from the pot on the end of his
blowpipe, and blows a small quantity of air into the mass,
manipulating it in the usual manner. Whilst still at a very high
temperature, it is detached from the blowpipe, and is probably allowed
to fall on the ground in a place where there is a current of cold air,
the exterior thus becoming suddenly chilled. When cold, these flasks
will bear very rough handling, and will withstand the blow of a hammer
on the outside, it being almost impossible to break them by striking
the bottom; the interior will also bear the blow of a leaden bullet
falling into it from a considerable height, but if a few grains of
sand be allowed to fall into it, or if the inside skin be slightly
scratched, the mass splits into fragments in the same manner as a
Rupert's drop. The examination of these curious phenomena leads us to
the subject of "toughened glass," as it has been termed. The invention
of rendering articles of glass less fragile, which has given rise to
so much public attention during the last year, is due to M. Alfred de
la Bastie, a French engineer. His process consists in heating the
glass to be toughened to a temperature close upon its softening point,
and then plunging it into a bath of oil, or into a mixture of
oleaginous substances kept at a much lower temperature. When this
operation is successfully performed, the glass acquires properties
very similar to those of Rupert's drops; it becomes much less fragile
than ordinary glass, but when sufficient force is employed to fracture
it, the whole flies into small pieces. It cannot be cut with a
diamond, but is immediately disintegrated when the outer skin is
scratched to a certain depth.

It is to be observed, however, that in particular cases it is possible
both to saw and pierce the toughened glass. M. de Luynes reports, that
when a square of St. Gobain plate glass that had been submitted to the
process of tempering was examined by polarized light, it showed the
appearance of a black cross, the arms of which were parallel to the
sides of the square. The glass was sawed in two, along the line of the
stem of the cross, without causing fracture. On examining the divided
glass with polarized light, black bands and fringes of colour were
observed, which, by their position, proved that the molecular
condition of the glass had changed; on placing one half of the divided
glass on the other half, the fringes and black bands disappeared--on
folding one half on to the other, the black bands presented the
appearance that would have been produced by glass of double the
thickness. These facts show, that the molecular forces on the glass
were arranged symmetrically in reference to the line of parting: and
we may conclude that toughened glass being in a state of tension,
similar to that of the Rupert drop, may be divided or pierced,
provided that the molecules of the pieces produced are able to
rearrange themselves into a stable equilibrium. Polarized light shows
the directions on which the division can be made with safety.

M. de Luynes, in his communication referred to above, gives an account
of some experiments performed on plates of glass of the same quality,
tempered by this process, and untempered; one or two examples will
suffice. A tempered plate measuring about[1] 6-1/2 inches by 5 inches,
and 2/10 inch thick, was placed between two wooden frames, and a
weight of over 3-1/2 ounces (100 grammes[2]) was allowed to drop upon
it from a height of more than 13 feet (4 mÃ¨tres[3]) without breaking
it. It only broke, when double the weight was employed from the same
height. A piece of ordinary glass under the same conditions broke,
with the weight of 3-1/2 oz. dropped upon it from a height 16 inches
(0Â·40 mÃ¨tre). Plates of toughened glass were allowed to fall on the
floor from a height, or were thrown to a distance, without breaking. A
rectangular piece of ordinary window glass, about 1/10 inch in
thickness, was bent into the form of a bridge, and then subjected to
the tempering process; placed upon the ground; it bore the weight of a
man easily without breaking. A commission, instituted by the French
naval authorities, to inquire into this process of M. de la Bastie,
has reported at some length on the subject. The following series of
experiments were tried with a view of ascertaining the comparative
power of resistance of tempered and ordinary glass. The plates
experimented upon were placed loosely in wooden frames constructed for
the purpose.

        [1] These numbers are approximate translations of the numbers
        given in the communication: no object could be gained in
        giving complex fractions.

        [2] 1 ounce avoirdupois weighs 28Â·349 grammes.

        [3] 1 mÃ¨tre equals 39Â·37 English inches.

_Rectangular plates about 21 inches_ (0Â·525 m.) _by 10 inches_ (0Â·248
m.) _and 1/6 inch_ (0Â·004 m.) _thick_.

The frame with the glass inserted was laid on the ground, and in the
middle of the plate a weight of more than 10 lbs. (5 kilogrammes[4])
was placed, and upon it as a base, other weights were placed, care
being taken to avoid all shock.

        [4] 1 kilogramme = 2Â·2 lbs. avoirdupois.

1Âº _Ordinary glass_, broke with a weight of about 70 lb. (35 kilos.)
having resisted weights of from 30 to 50 lb.

2Âº _Toughened glass_ resisted fracture until a weight of more than
510 lb. (255 kilos.) had been added, and then was not broken. The
experiment was not carried to its limit for want of weights.

_Rectangular plates, about 13 inches_ (0Â·325 m.) _by 10 inches_ (0Â·248
m.) _and 1/5 inch_ (0Â·005 m.) _thick_.

These plates were allowed to fall flat on to a floor of wood or thrown
to a distance and allowed to fall.

1Âº _Ordinary glass_ allowed to fall flat from a height of 1-2/10 inch
(0Â·03 m.) was broken at the first trial.

2Âº _Toughened glass._ Thrown to a height 6 feet 6 inches (2 mÃ¨tres)
and to a distance of 13 feet (4 mÃ¨tres) was also broken at the first
trial. The piece, however, which had sustained the weight of 510 lb.
did not break till the fourth trial.

_Rectangular plates, about 10 inches_ (0Â·245 m.) _by 6 inches_ (0Â·157
m.) _and 1/4 inch_ (0Â·007 m.) _thick_.

These plates were subjected to the same kind of tests as the
foregoing. After raising them to a given height they were allowed to
fall flat upon a wooden floor.

1Âº _Ordinary glass_ raised to a height of 20 inches (0Â·50 m.) was
broken on falling.

2Âº _Toughened glass_ resisted successive falls of from 20 inches
(0Â·50 m.), 32 inches (0Â·80 m.), 5 feet (1Â·50 m.), and 5 feet 7 inches
(1Â·70 m.), but was broken when dropped from a height of 6 feet 6
inches (2Â·0 m.).

_Rectangular plates about 10 inches_ (0Â·245 m.) _by 6 inches_ (0Â·157
m.) _and 1/5 inch_ (0Â·006 m.) _thick_.

Placed in the frames, they were held in position in the rabbets by
laths nailed to the sides so as to prevent any play. The frames were
raised to different heights and allowed to fall in such a manner as to
cause as much vibration as possible.

1Âº _Ordinary glass_ was broken with a fall of about 2 feet (0Â·60 m.).

2Âº _Toughened glass_ resisted falls from heights of 3 feet 3 inches (1
mÃ¨tre), 6 feet 6 inches (2 mÃ¨tres), 8 feet (2Â·50 m.), 9 feet 9 inches
(3 mÃ¨tres), and 14 feet 6 inches (4Â·50 m.). It was only broken by a
fall of 19 feet 6 inches (6 mÃ¨tres).

_Rectangular plates 6 inches_ (0Â·158 m.) _by 4-3/4 inches_ (0Â·120 m.)
_and 1/5 inch_ (0Â·006 m.) _thick_.

These plates were placed in the frame on the ground, as has been
previously explained. Known weights falling from known heights were
made to strike the plates exactly in the centre. The weights consisted
of bronze spheres, one weighing 3-1/2 oz. (100 grammes) and another of
twice that weight.

1st. _Ordinary glass_ resisted the weight of 3-1/2 oz., falling from
heights of 8 inches (0Â·20 m.), 12 inches (0Â·30 m.), 16 inches (0Â·40
m.), but was broken by a fall of 20 inches (0Â·50 m.).

2nd. _Toughened glass_ resisted the blow of the 3-1/2 oz. weight
falling from heights of 20 inches (0Â·50 m.), 40 inches (1 mÃ¨tre), 60
inches (1Â·50 m.), and 6 feet 6 inches (2 mÃ¨tres). The 7 oz. weight
(200 grammes) being substituted, the plate was broken by it, falling
from a height of 60 inches (1Â·50 m.).

_Rectangular plates, 6 inches_ (0Â·158 m.) _by 4-3/4 inches_ (0Â·120 m.)
_and 1/6 inch_ (0Â·004 m.) _thick_.

The same conditions were maintained as in the previous trial.

1st. _Ordinary glass._ The 3-1/2 oz. weight was allowed to fall from
heights of 1 foot (0Â·30), and 16 inches (0Â·40 m). It was broken by the
second blow.

2nd. _Toughened glass._ This resisted the 7 oz. weight falling from
heights of 2 feet 4 inches (0Â·70 m.), and 2 feet 8 inches (0Â·80 m.),
but broke when the weight fell from 39 inches (1 mÃ¨tre).

It appears then from these experiments, that toughened glass will
resist a blow five times as great as ordinary glass, and will bear
seven times as great a weight.

I have now detailed most of the useful experiments which have been
made by competent observers upon toughened glass, as well as some
which have been conducted in my own laboratory. The result of my own
personal investigations I will now lay before the reader. I was
consulted some time ago by a gentleman interested in the introduction
of toughened glass into this country, as to whether this kind would
become untoughened in time. I feel no hesitation in stating that when
the process has been perfectly done, the glass will remain in the same
state for any length of time, provided it be not treated in any way
which is calculated to rupture the external hard bond that holds
together the inner particles of the glass. I feel quite sure, that no
fear of this kind need interfere with the benefits, whatever they may
be, which are to be derived from submitting glass articles to the
toughening process.

A tumbler which had been toughened in Monsieur de la Bastie's works,
was, in my presence, thrown upon the ground, yet it did not break. It
was a large soda water glass. I kept it for some time, and after
considering the matter carefully, I felt, that if it were thrown down
in such a way that the whole of its side, from base to rim, came in
contact with the ground at once, and it then stood this test, it would
prove that the whole of the glass was in the condition of the Rupert's
Drops, and would therefore bear the concussion without fracture. I
held the glass and let it fall, so that it actually reached the hard
floor on its side. It immediately broke all to pieces. Now on the
first occasion when this glass was thrown down, it was tossed somewhat
upwards into the air, and the bottom being heavier reached the ground
first, and it did not break. I have also seen in glass-houses, where
the tempering process is carried on, tumblers thrown down in a similar
manner, and I noticed, that whenever they fell upon their bottoms,
they were uninjured, as also in cases where they fell upon their rims
in such a manner, that the curve of the rim acted as an arch, as in
the old trick of turning a wine-glass off the table so as not to
break; but in other cases where the tumblers fell flat upon their
sides, fracture followed. I carefully gathered together the pieces of
the large tumbler which I broke myself in this manner, and examined
them, and found that the solid bottom was broken in the same manner as
the Prince Rupert's drops break, viz., into a large number of small
pieces, having in all respects similar properties. The glass for an
inch or two above the bottom broke into small pieces, but larger than
those into which the bottom itself broke, and the upper portion of the
tumbler was fractured just as an ordinary tumbler would be. On careful
examination, microscopic and otherwise, the small pieces were found to
have the character of Prince Rupert's, whereas the larger from the
upper part of the glass had none of these characteristics in the
slightest degree.

These observations led me to perform an experiment. A toughened
tumbler was filled with plaster of Paris, which was allowed to set.
Its outside was then encased in plaster of Paris, and when the whole
was hardened, a pair of pincers were applied to a portion of the
tumbler's rim, and with a violent wrench the tumbler was broken. A
rather smart shock was communicated to the arm of the operator, very
much resembling, as he said, the shock of an electrifying machine. On
removing the plaster of Paris, it was found that the whole of the
tumbler was fractured, and, as will be seen by the accompanying
illustration, in a manner similar to that which has already been
described.

From this and other similar experiments, I was led to the conclusion
that none of the toughened articles which have cavities in them, have
thoroughly undergone the toughening process.

Having been requested to attend a series of experiments performed by a
glass manufacturer in London, which consisted in the manufacture of a
number of toughened glass tumblers, I noticed certain facts which led
me to form conclusions as to how it was that the tumblers, the
fracture of which I already explained, break in this peculiar manner.
I will first describe the way in which these tumblers were made and
toughened. By the side of the glass blower there stood a metal vessel,
about three feet six inches high, and, perhaps, from two to two feet
six inches in diameter. This was filled with melted fat or oil of some
kind at a temperature of about 80Â° Fahr. Inside this vessel, which was
open at the top, there was a wire cage, with a trap door at the bottom
about one foot in diameter, and of about the same depth. The glass
blower, after finishing his tumbler on the pontil, held the pontil in
a horizontal position over this metal vessel, struck it a smart tap,
and the glass tumbled off into the wire cage. The glass was at a very
high temperature. In almost every instance the glass fell into the
melted fat, as a glass thrown in a similar manner will fall into
water. It sank gradually bottom downwards, and the liquid guggled into
it as it sank. Here, then, it is clear that every portion of the hot
tumbler did not come in contact with the oil at the same moment, in
fact there was an appreciable lapse of time before the tumbler
disappeared beneath the surface of the liquid. Now there must be a
limit as to the temperature of the article to be tempered and of the
liquid by which it is to be tempered, that is to say, if at a certain
temperature glass can be tempered by being plunged into the liquid of
a certain temperature, if these temperatures are varied similar
results will not follow. The upper portions of the glass coming in
contact with the tempering liquid at a lower temperature, as they must
have done, were not properly tempered, and this I have clearly proved
by the facts I have already stated. From these remarks it seems
tolerably clear that, until some method is devised of bringing all the
parts of the heated glass in contact with the cooling liquid
simultaneously, the tempering of the article cannot be perfect
throughout its whole surface. As I desire, and very sincerely, that
these processes should be brought to perfection so as to render them
useful, I willingly give this result of somewhat lengthened
investigations to those whom it may commercially concern, and I hope
that they will find, on investigating the matter, that my observations
have been tolerably correct, and that they will be able to devise a
method which will remedy in many cases manifest imperfections of their
present system. All the accidents which have happened to tempered
glass, which have been recorded in the newspapers, can be accounted
for on the principle which I have just endeavoured to explain, for
there must be instability, where the bonding material of the internal
particles of the glass is in different states of hardness; so that
there is no difficulty in conceiving how a gas globe could break
apparently spontaneously, for a portion of it which was not fairly
toughened might be exposed to a somewhat sudden rise of temperature,
produced, it may be, from a draught blowing the flame upon that
particular spot. Articles such as saucers, made of glass, which, being
flat, or nearly so, can be plunged into the tempering liquid with
great rapidity, are usually tempered all over, and these, when
toughened, can be thrown about and allowed to fall on hard floors with
impunity, thus proving the facts which I have endeavoured to
establish. I hope to be able to continue my investigations, and should
they be worth anything, will give the results of them to the public.
Before quitting this subject, I shall make a few remarks upon the
process for toughening glass, which is said to have been purchased by
the Prussian Government.

This process is described as consisting in the application of
superheated steam to the glass, brought up to a temperature near to
its melting point. Having facilities for making experiments of this
kind, I have had them tried with great care, but in no case have I met
with a satisfactory result. This probably is owing to the fact, that I
did not comply strictly with the condition of the experiments
performed by the German chemist who is said to have made the
invention, nor do I see from analogy how this process is likely to
effect a change in the glass similar to that arising from M. de la
Bastie's dipping process.

If glass, instead of being taken from the annealing kiln at the proper
time, be left exposed in the hot part of it, at a temperature just
below that at which it softens, it will be found to become gradually
opaque on its surface. Some experiments were performed many years ago
by RÃ©aumur, who exposed pieces of glass, packed in plaster of Paris,
to a red heat, which became gradually opaque, and lost altogether the
character of glass, the texture of their material becoming
crystalline, and also effected by sudden changes of temperature. Glass
treated in this way was called RÃ©aumur's porcelain. All glasses do not
undergo this change with equal rapidity, and some do not experience it
at all; but the commoner kinds, such as bottle glass, are the best to
experiment upon, for the more alumina that it contains--and it is
known that bottle glass contains a considerable quantity--the more
readily does it undergo this change, which is called _devitrification_.
In what it consists, is not at present well understood, but it offers
a field for investigation, which may produce results of very
considerable benefit to manufacturers of glass.

_Soluble Silicates._--An article on glass in a modern scientific work
like the present would not be complete without a notice of the
manufacture of soluble glass and the uses to which it has been and may
be applied. It has already been mentioned that when silica or sand is
fused with an excess of alkali, the resulting glass is soluble in
water.

Soluble glass is made on a large scale in three different ways. First
of all, if flints, that is, black flints, which are found in chalk, be
heated to a white heat, they lose their black colour and their
hardness, and are easily crushed to small pieces; and if flint in this
condition be placed in a wire cage and put into a jacketed iron
digester, that is, an iron digester which has an inner and an outer
skin, with a free space between the two, so that steam may be forced
into it from a boiler under pressure; and if the digester be screwed
down tightly with an iron cover, and steam then be allowed to pass
into the space between the two, the temperature can be raised at
pleasure, according to the pressure under which the steam is
introduced. If the valve of the boiler be loaded with a 60-lb. weight,
the temperature of the water warmed by the steam will rise
considerably higher than that of ordinary boiling water; and if this
water be saturated with caustic soda, it will dissolve the flints
slowly, forming silicate of soda, that is to say, the silicic acid of
the flint will unite directly with the soda of the solution, and
silicate of soda will thus be obtained. For certain applications, the
silicate so formed is not sufficiently pure, because the soda used
often contains a certain amount of sulphate, which will remain with it
in the solution of silicate that is drawn off from the digester. This
sulphate is very objectionable for certain applications of silicates,
because it crystallizes out, and so destroys the substance, which the
silicate is intended to preserve.

Another and a much better method is to heat together the silica in the
form of sand with alkali, either potash or soda, in a reverberatory
furnace, and as the glass becomes formed, to rake it out into water,
and then gradually to dissolve it by boiling in suitable vessels. Here
the sulphate, if it existed in the alkali, is decomposed by the
silicic acid, and the sulphuric acid passes off through the flues of
the reverberatory furnace.

There is also a very ingenious way of making silicate of soda,
discovered by Mr. Gossage, and performed as follows: common salt is
heated to a high temperature and volatilized, and in this condition is
brought into contact with steam also at a high temperature, when a
double decomposition takes place. Steam is composed of oxygen and
hydrogen; common salt, of sodium and chlorine. The chlorine of the
common salt unites with the hydrogen of the steam, and the oxygen of
the steam with the sodium, so that hydrochloric acid and oxide of
sodium are formed. Now, if these two substances at this high
temperature were allowed to cool together, the action would be
reversed, and the re-formation of steam and chloride of sodium would
be the result; but in the strong chamber lined with fire-clay, in
which these vapours are brought into contact, silica is placed in the
form of sand made up into masses, and when the oxide of sodium is
formed, it unites with the sand to make silicate of soda, and thus is
removed from the action of the hydrochloric acid, not entirely, but
sufficiently to produce a large yield of silicate of soda.

The properties of silicate of soda, as applied to the arts, are
somewhat different from those of silicate of potash, so that one
cannot always be substituted for the other. Both these substances are,
when in solution and concentrated, thick and viscid, and have the
property of causing paper, wood, &c., to adhere when applied as a gum
or glue, and hence have been called "mineral glue." In a dilute state
they can be used for coating stone, brick, or cement, and have the
power of rendering them for a time waterproof, or nearly so, and of
preventing the action of atmospheric influences, which too often
produce the decay of some of the softer stones used for building as
well as for cement. It has already been stated, that when carbonic
acid is passed through a solution of silicate of soda, silica will be
precipitated. Now, inasmuch as there is carbonic acid in atmospheric
air, when these solutions are applied to the surfaces of a building,
they will be acted upon slowly by the acid, and silica will be
precipitated in the pores of the material to which the silicates are
applied. But this operation is extremely slow, and, before it can be
thoroughly completed, the silicates, being soluble, will get in part
dissolved out by rain and moisture, and it is therefore advisable to
use with them some material which will, by a double decomposition,
form a silicate insoluble in water. The silicate, however, which is
formed, should have cohesion amongst its particles, so that it will
not only adhere to the stone itself, but its own particles will adhere
to one another when it gets dry. Various methods have been tried to
cause this insoluble substance to be formed upon the surface of
stones, so as to fill up its pores and to make a protecting cover for
it; but most of them have signally failed, because the new silicate
produced by double decomposition has not had the necessary coherence
amongst its particles. If a solution of chloride of calcium be added
to one of silicate of soda, a silicate of calcium will be
precipitated, and it was therefore thought, that by applying to a
stone successive washes of silicate of soda and chloride of calcium,
an insoluble silicate of calcium would be produced in the pores and on
its surface. It is true that such a silicate is precipitated, and
that, if the silicate employed be in excess of the chloride of
calcium, the particles will be glued together by the adhesive powers
of this silicate when it dries; but then the action of moisture upon
it is to cause it to run down the surface of the building, and set
free the particles of silicate of calcium which it held in
combination. Other processes of the same kind have been tried, and
with similar results; one great difficulty in the way of the success
of this method of applying silicates being that, from the peculiar
colloidal or gluey nature of the silicate, it does not penetrate to
any considerable depth into the stone, and, if laid on first, prevents
the penetration, as far even as it has itself gone, of the solution of
chloride of calcium. If the chloride of calcium be used before the
silicate, it will penetrate farther than the solution of silicate is
able to reach, so that it is impossible to obtain, even supposing the
substance to be used in equivalent proportions, a complete
decomposition of the one by the other.

The great object to be attained in the preservation of stone by
any silicious process, is to use _one_ solution possessing the
substances which, when the water has evaporated, will form a
perfectly coherent mass for the protection of the stone surface. The
depth of penetration, if it is sufficient to protect the outside of
the stone from the disintegrating action of the atmosphere, need not
be carried much more than one-sixteenth of an inch below the surface,
for when old stones which have long been in positions in buildings,
and which have not decayed at all, are examined, it will be found
that they are covered with an extremely thin film of a hard
substance, not thicker than a sheet of writing paper, which has for
ages protected and preserved them from decay. This film is produced
by a determination from the inside to the outside of the stone of a
silicious water, which existed in it in the quarry, and which, when
the stone was placed in the building, gradually came to the surface,
the water evaporating and leaving behind it a thin film of silica, or
of a nitrate--most likely the latter.

If alumina be fused with potash, aluminate of potash, soluble in
water, is made; if, however the solution is too concentrated, a
certain quantity of the alumina will be precipitated; but if it be
dilute, the whole of the alumina will remain in solution. When
aluminate of potash of specific gravity 1Â·12 is mixed with a solution
of silicate of potash of specific gravity 1Â·2, no precipitate or
gelatinization will take place for some hours; the more dilute the
solution, the longer will it remain without gelatinization, and of
course the thinner it will be, and the greater power of penetration it
will have when applied to a porous surface. When solutions of
aluminate of potash and of silicate of potash of greater density are
mixed together, a jelly-like substance is almost immediately formed,
and sometimes even the whole mass gelatinizes. If this jelly be
allowed to dry slowly, it will contract, and at last a substance will
be left behind sufficiently hard to mark glass, though the time for
this hardening may be from one to two years; and on examination it is
found that this substance has very nearly the same chemical
composition as felspar, and is perfectly insoluble in ordinary mineral
acids. Now, suppose a dilute solution of this mixture to be applied to
the surface of stone, the silicate and aluminate of potash will
gradually harden and fill up the interstices of the stone; and as both
the substances entering into combination are contained in the same
solution, they will both penetrate to the same depth. Inasmuch as the
artificial felspar is not acted upon by destructive agents which would
disintegrate the stone, it becomes a bonding material for its loosened
particles, and at the same time gives a case-hardening to the stone,
which no doubt will as effectually protect it against atmospheric
influences as in the case of the hardening of the natural one. We have
a tolerable guarantee that this will be so, if we consider the number
of enduring minerals into the composition of which silica, alumina,
and potash enter, and also of the almost imperishable character of
granite, which is so largely composed of felspar. Many experiments
have been performed on an exhaustive scale with these materials, and
in every case it has been found that they have answered the
expectation of those who have thus tested them. It is, however,
necessary to state, that in making these experiments, great care must
be used to employ the mixed substance in solution before
gelatinization has set in, for if this has occurred, even to the
slightest extent, a surface coating is formed on the stone, which, not
having formed a bond with it, easily rubs off.

Another application of soluble silicates in this or other forms is to
render walls of buildings which are porous, waterproof. A colourless,
transparent material which can effect this object is doubtless
desirable, as anything like an opaque wash, if applied to brick-work,
would destroy the colour of the bricks, and therefore the character of
the building constructed with them. The silico-aluminate of potash may
be used for this purpose, as above directed; and even silicate of
potash alone, provided it be in sufficient quantities, will answer
well, if from year to year, for two or three years, the application be
renewed, so as to fill in spaces, wherever the silicate may have been
in part dissolved out. When the silicate of potash alone is used, the
action of the carbonic acid of the air in precipitating the silica is
depended on, and while this action is going on, portions of the
silicate not acted on will be dissolved out.

Many years ago, an effort was made in Germany to revive the ancient
art of fresco painting, and with very considerable success. It was
found, however, that our climate is not suited to the permanence of
this method of decoration, nor indeed is any climate absolutely
suitable, because in fresco painting, the surface only of the lime is
coloured with pigments laid on, so that any influence which would
destroy the lime surface would cause the removal of the pigments; and
from the porous nature of the surface of the work after it is
completed, absorption of moisture will from time to time take place,
causing the adhesion of dirt and other foreign substances which may
fall upon it, and which it is almost impossible to remove without
detriment to the picture. Dr. Fuchs, of Munich, discovered a method of
painting with soluble silicates, which has been tried with
considerable success in Berlin by the late Professor Kaulbach. On a
properly prepared ground, the painting was executed in colours mixed
with water, which, when dry and the painting finished, were fixed to
the wall by the application of soluble silicates. For the preservation
of the work, Dr. Fuchs mainly relied upon the action of atmospheric
carbonic acid. Now, when carbonic acid acts upon silicate of soda or
silicate of potash, we have already seen that the silicic acid is
precipitated in the hydrated form, and that the carbonic acid has
united with the soda or potash to form carbonate of soda or carbonate
of potash. These substances being left in the painting and penetrating
to a certain depth beneath its surface, must find their way out, and
in almost every instance have done so in the form of an efflorescent
substance, which has caused the picture to have the appearance of
being mildewed over its surface. Sometimes, however, sulphates occur
in the ground, and then sulphates of soda and of potash have been
formed, injurious to the permanence of the surface of the picture,
because they crystallize and force off portions of the lime and sand
of which the surface is composed. The effect of the efflorescence of
the carbonates on the surface of a silicious painting may be seen in
the famous picture of the meeting of Wellington and Blucher, in the
House of Lords, painted by the late Mr. Maclise, R.A. When, however,
the solution of aluminate and silicate of potash is used with the
pigments on a properly prepared ground, there is no fear of this
efflorescence taking place, and paintings executed with it have stood
for many years, without giving any signs whatever of decay.

To those interested in this subject, it is desirable that they should
perform a series of experiments themselves, and ascertain the best
methods of practically applying this vehicle in the execution of large
mural paintings. They will find that, although at first they may meet
with some difficulties, yet after a while these difficulties will
vanish, and they will have a material to work with, which will meet
all their requirements.

In an article so brief as the present, it is impossible to enter fully
into all the details of the manipulation of this particular process of
painting; it is, however, most desirable to give a short account of
the method of preparing the ground and of applying the colours,
leaving the rest to be learned from practical experience.

Angular fresh-water river sand, well washed, should be mixed with
sufficient lime to cause it to adhere to the wall on which it is
placed, and this in all cases should be freshly plastered in the
ordinary way. No plaster of Paris (which is sulphate of lime) should
be used in the preparation of the groundwork. The coating of fine sand
and lime is laid on to a depth of about an eighth of an inch, and when
dry, an application of dilute silicate of potash should be made, in
order to bond together the particles of sand which, owing to the
employment of so small a quantity of lime, can be readily brushed off.
As soon as these particles are well fixed together and do not come off
when the hand is passed over the surface of the wall, the ground is in
a fit state for the commencement of the painting. The colour should be
used with zinc white, and not with lead white, and, of course, they
must be in the state of fine powder, and not ground up with oil or any
such material. The artist can use his mixture of silicate of alumina
and aluminate of potash of the strength already described; he may,
when desirable, dilute it to a certain extent with water, but he
should not do so too much. He can then paint with it just as he would
with water in water-colour painting; and if he finds that any portion
of his colours, after they are dry, are not sufficiently fixed upon
the wall, he can then with a brush pass over them a coating of the
clear liquid, used a little stronger. When the whole work is finished,
it will perhaps be desirable to give it one or two coats of a very
dilute solution of silicate of alumina and aluminate of potash. After
a time, owing to the contraction in drying of this material, it would
be advisable--say, after the lapse of two or three months--to again
apply a coat of it somewhat stronger; and again, if after a year, or
more than a year, it should appear that any portions of the surface
were becoming loose, another application of the mixed silicate of
alumina and aluminate of potash to these loosened parts alone will be
desirable. This repetition may appear to some to be an objection to
the process, but it is not so, however; for in the formation of those
natural substances, such as flints, which we find so hard, no doubt a
very great lapse of time occurred in the induration of the gelatinous
silica which formed them. Neither do we object from time to time, at
intervals of years to renew the coats of varnish on oil paintings, in
order to preserve them or to bring out afresh the brilliancy of their
colours.

The soluble silicates are frequently used as bonding materials in the
manufacture of artificial stone and cement, very good results having
been attained. The objection, however, to their employment for these
purposes is the expense of the material of which they form a
constituent part, and it seems almost impossible ever to bring it into
competition with dressed natural stone. But for ornamental purposes,
from the plastic nature of the substance when in the wet state, it can
be pressed into moulds, and wherever plaster mouldings are admissible,
no doubt this material would be useful for certain kinds of
ornamentation. Some years ago, Mr. Ransome, of Ipswich, after having
made his artificial stone with sand and silicate of soda, heated it in
ovens, so as to produce a hard and semi-vitrified mass. A church, the
mouldings of which are made of this stone, may be seen at the bottom
of Pentonville Hill, London; and certainly as to durability, there is
no doubt that the substance has answered very well. But from
difficulties in manipulation and other reasons, that gentleman gave up
this method of making artificial stone, and is now working another
process which yields far better results. Silicate of soda is mixed
with sand (generally Aylesford sand), and after the mixture is moulded
and dried, it is exposed to the action _in vacuo_ of chloride of
calcium in solution. Whether the whole mass is placed in a vacuum
chamber and then charged with chloride of calcium; or whether a vacuum
is formed on the under side of the substance, and the chloride of
calcium solution caused by suction to filter through it, is uncertain.
However, whatever be the manipulative processes, the result is the
same, and appears to be extremely satisfactory.

Soluble silicates produce very remarkable results when mixed with
certain substances. If silicate of soda or potash be mixed with white
lead, in a very short time it sets into a hard substance, just as does
plaster of Paris when mixed with water. If powdered pumice-stone or
sand, in the proportion of eight parts to one of carbonate of lead, be
mixed together with soluble silicate, a very hard and coherent mass is
obtained, and there seems no reason why a mixture of this kind, in
which pumice-stone is used, should not be employed for the purpose to
which pumice-stone is usually applied. It would have the advantage of
being easily moulded into forms, so as to suit mouldings, which might
by it be much more accurately and expeditiously smoothed down (as in
the case especially of picture-frame mouldings), than they can be by
the ordinary pumice-stone.

Another very important application of soluble silicates is the
rendering of wood incombustible. Many experiments have been performed
which show that when wood is thoroughly impregnated to a depth of a
quarter of an inch or more with silicate of soda, it will not flame,
but will only char. Now, supposing that the constructive timbers of a
house were worked, and then placed in suitable vessels and saturated
with silicate of soda, they would then be rendered practically
fireproof, or at least it would take a very prolonged exposure to heat
to cause them to smoulder away, while at no period of this time would
they burst into flame. From the peculiarly gluey nature of these
soluble silicates, they do not penetrate readily into porous
substances; it has therefore been suggested that the impregnation of
the wood should take place in vacuum chambers, just in the manner that
the creosoting process for preserving railway sleepers is at present
performed. It is most certainly advisable that the wood should be
worked before being exposed to the silicating process, for that would
render it so hard, that it would considerably increase the cost of
labour in cutting and planing it.

At the commencement of this article, it was stated that silicic acid,
or silica, could be made soluble in water. Some very interesting
experiments were performed by the late Dr. Graham, Master of the Mint,
which gave rise to the discovery of the process of dialysis. If some
silicate of soda be mixed with water, so that not more than 5 per
cent. of silica be in the solution (rather less is better), and if
some hydrochloric acid be then added in sufficient quantity to make
the liquid distinctly acid, and the mixture be placed in a dialyzing
apparatus, the chloride of sodium formed by the union of the chlorine
of the hydrochloric acid with the sodium of the silicate of soda will
pass out through this dialyzing membrane, leaving hydrated silica
behind, which will remain in solution in the water with which the
silicate was mixed. The dialyzing apparatus is constructed in the
following manner; a sort of tambourine ring is made with gutta percha,
in place of wood, from 8 to 10 inches or even more in diameter, the
depth, being about 2 inches. Another ring of gutta percha, of about an
inch deep or even less, is made so as to fit tightly outside the
tambourine; a piece of vegetable parchment is then moistened and
placed over the tambourine, and the thinner ring is pressed over it,
so as to secure it tightly. This is the dialyzing vessel, and it is
into this that the mixture of silicate and hydrochloric acid must be
put. The solution should not be more than an inch deep in the
dialyzing vessel, which is then made to float upon distilled water in
a larger vessel of suitable size. The distilled water should be
changed every day, until no precipitate can be obtained in it with
nitrate of silver, and when this point is arrived at, all the chloride
of sodium will have passed through the vegetable parchment into the
larger vessel of water, and nothing but silicic hydrate will remain
behind in solution. If this liquid be allowed to stand for some time,
it will gelatinize, and later on the jelly will contract, becoming
extremely hard, so that lumps of it, when broken, will in their
fracture resemble that of flint. No doubt, at some future period, some
one will discover a method of rendering this condition of silica
useful in the arts.

Soluble silicates are very useful as detergents. A small quantity of
silicate of soda mixed with hard water renders it valuable for washing
purposes. Silicate of soda is also used in the manufacture of the
cheaper kinds of soap. We can hardly speak of it as an adulteration,
because it renders the soap with which it is combined much more
powerful in its cleansing action. I suggest to those interested in the
application of science to the arts, that this subject will no doubt
well repay experimental investigations.

It is much to be wished that those engaged in this branch of art and
manufacture, and who have some knowledge of chemistry, would turn
their attention to getting a better and more perfect method of making
coloured pot-metal glass. I have been engaged for some time, and still
am engaged, in experiments to effect this object. But inasmuch as my
engagements are very numerous, and I cannot give the proper time to it
I desire, I therefore take the liberty of suggesting to others the
ways in which I am working, that they may be able to arrive at good
results more speedily probably than I shall be able to do. If sulphate
of copper be mixed with silicate of potash, silicate of copper will be
precipitated. Now, if this be carefully washed and dried, it will be a
silicate of a definite composition, and I propose to use such
silicates as these with ordinary glass mixtures, in order to impart
the particular colour which the oxide employed has been already
described as giving to the glass. Silicate of manganese is prepared in
a similar way to the silicate of copper; silicate of cobalt, and other
silicates, can be used as staining materials for colouring glass.
These mixed in due proportion would give tints, and would, I do not
feel the slightest doubt, produce colours with much greater certainty
than they are now produced, and tints hitherto unknown could be made
to the great benefit of the glass-painter.




FURNITURE AND WOODWORK.

BY J. H. POLLEN, M.A., South Kensington Museum.


I propose in the following pages to give some account of the materials
used in making furniture, and of the arts applied to its decoration.
From the earliest ages of society, when men moved about in tribes,
they had in their tents of camels' hair simple necessaries, such as
their wants required. Before people were gathered into distinct
nations, or cities built with walls and gates, there were still
certain human wants that must needs be supplied; and the objects that
were needed to enable mankind to live with convenience and decency
were found in their furniture. To this very day we may see Arab tribes
wandering over sunny deserts, seeking pasturage, sowing here and there
an acre of wheat or barley, or gathering dates. Their camels and
dromedaries are their waggons, their horses are their friends, their
families and those of others that make up their tribe are their only
nationality. Yet they furnish in some sort the temporary homes which
they shift from one spring of water to another, as the patches of
grass or grain grow up and ripen. Their chief wants are, a cloth
strained over three staves to make a house, mats or carpets to lie on,
a few bowls to cook in, saddles of wood, and a few baskets or chests,
made of light sticks fastened together.

In later periods of history and in more conventional states of
society, we shall find this primitive type of furnishing carried out
with growing splendour. In the West and in the East, in ancient and
mediÃ¦val times, great rulers, though constantly in the saddle, have
been followed by enormous trains of camp followers, by whom costly
furniture, hangings, vessels of plate, and other luxuries, have been
carried for the convenience of the leaders and warriors of moving
hosts; and of course this splendour was the measure of the state and
magnificence kept at home. The wealth or feudal state, shown in the
furniture of old castles and palaces, extended not only to halls and
rooms, but to dresses, and armour, weapons, the furniture of horses,
tents, and other objects that could be carried on distant expeditions.

Ancient nations have been as well, and more splendidly, if less
conveniently, provided with furniture for their houses than modern
ones. It happens that there are distinct records of many kinds,
showing what wealth and elaborate decoration some of the oldest races,
such as the Assyrians, the Egyptians, the Persians, and the Greeks,
bestowed on their thrones, beds, chairs, and chariots. Beds of silver
and gold are mentioned in Esther i., and the curtains of the bed of
Holofernes were covered with a canopy of purple and gold, with
emeralds and precious stones (Judith x. 19; Esther i.). Modern princes
in India continue to devote their jewels and gold to similar uses. It
must be borne in mind also, that this kind of splendour is an
investment of property in times and countries in which banks,
insurance offices, government funds, and other organized means of
investing money are unknown.

Silver, if not gold, has been used occasionally, not only in the East,
but in Europe, for seats, tables, even the frames of pictures and
mirrors. The royal apartments in Whitehall were completely mounted
with hammered and filagree silver furniture in the seventeenth
century. Carlyle records of Frederick the Great, that silver ornaments
were kept in his palace, and turned to account under the exigencies of
war. But of furniture generally, wood is the readiest and most proper
material. It is handy, easily worked, light to carry about, and may be
manufactured with or without decorations of carved work, or of any
other kind. Hence, in giving an account, whether historical or
mechanical, of furniture, I class it under the more general head of
woodwork. Any other materials, either for the framing or ornamentation
of furniture, are exceptional. The remarks now to be submitted to the
reader will refer to wood that is manufactured, though I shall not
enter on the interesting subject of wood structure, which has been
applied to such noble and elaborate uses, and of which such splendid
monuments of many periods still remain for us to study.

Most of the methods used for decorating woodwork made up into
furniture are still in regular use, and the processes of putting it
together are the same as they have always been. The reader may satisfy
himself on this point any day by a walk in the Egyptian rooms and in
the Nineveh galleries of the British Museum. In both these sections of
that wonderful collection, there are remains of woodwork and of
furniture, made of wood three or four thousand years old, such as
stools, chairs, tables, head-rests or pillows, workmen's benches of
Egyptian manufacture, fragments less complete of Nineveh make that
have been portions of various utensils, and precious articles of
sculptured and inlaid ivory that have been inserted into thrones and
chariots. These pieces of furniture have been mortised together, or
joined by dowels, dovetailed at the angles, glued, nailed, or, in
short, made up by the use of several of these methods of junction at
the same time. And no great changes have been introduced in the
various ways of ornamenting furniture. The Egyptian woodwork was
painted in tempera, and carefully varnished with resinous gums. It was
inlaid with ebony and other woods, carved, gilt and, perhaps,
sparingly decorated with metal ornaments. The Greeks inlaid chests and
tables with carved ivory and gold, sometimes relieved with colour. The
Romans, who made much furniture of bronze, cast, inlaid, damascened
and gilt, made much more in wood, which they stained, polished,
carved, and inlaid. MediÃ¦val furniture was put together with mortises,
tenons and glue, and was gilt and painted; the painting and gilding
being laid on a ground prepared with the utmost care, and tooled and
ornamented in the same way that bookbinders ornament leather. At a
later period, a beautiful manufacture was carried on in various parts
of Italy; a sort of mosaic in very hard stone, such as agate, lapis
lazuli, and other precious materials. The Italians also used these
beautiful stones inlaid in ebony. But the furniture most valued in
modern times has been that which owes its name to Boulle, a French
artist of the seventeenth century; and the marquetry, or wood mosaic
surface decoration, which reached so high a standard of excellence
during the last thirty years of the eighteenth century in France.

The former of these two classes of manufacture made, if not
originated, by Boulle (and I am inclined to think that he was not the
first maker), was a marquetry, or surface decoration, not composed of
various woods, but of tortoiseshell and brass, with the occasional
introduction of other metal, and with metal enamelled in blue and
other colours. The materials principally in use, however, in Boulle
marquetry are tortoiseshell and brass. In the older work, viz. that of
the seventeenth century, the tortoiseshell is dark, and left in its
natural hue. In later Boulle, called new Boulle, the tortoiseshell is
reddened by colour, or by gilding laid under it. There is much grace
and variety in the delicate arabesque designs in which one material is
inlaid in the other. Parts of the surfaces are sometimes diapered, as
a contrast to the free lines and curves of other parts. The inlaid
surface of Boulle work is framed in by borders, cornices, or handles
of brass or gilt bronze, giving a massive architectural character to
the whole.

Thus if we look back to the history of furniture, not only will every
kind of splendid material be found devoted to the manufacture or
decoration of it, but the best art too of many different periods that
money could command. It is in the late times of antiquity, and since
the period of the Renaissance in modern times, that works of art have
been kept on shelves or gathered into galleries. Many works of great
masters, such as the chest of Cypselus, and the chairs of the great
statues of ivory and gold, were prepared for celebrated shrines and
temples in the cities of Greece. It was but the excessive wealth of
great patricians in Rome and Constantinople that led to their becoming
collectors, whether of sculpture, painting, or sumptuous silver plate.
The chief object of rich and accomplished men in most ages of luxury
and refinement has been, to make the house, its walls, ceilings,
floors, and necessary or useful furniture, costly and beautiful. It
was the same in the days of Donatello, Raphael, Cellini, and Holbein.
Chests and trays were painted, together with gems, dies, brooches;
table plate was modelled and chiselled; while chairs of wrought steel,
or tables, cabinets, and other pieces of rich furniture, were either
designed or carried into execution by these masters with their pupils
and followers. In some instances, as, e.g., in that of the famous
Pomeranian cabinet, in the Kunst Kammer in Berlin, a long list has
been preserved of artists and craftsmen of note in their day, who
combined to produce monumental examples of actual room furniture.

It cannot be denied that though great pains are taken and much expense
is incurred in modern furnishing, the habits of the day lead rather to
the search for comfort than for grace or beauty; and convenience
rather than intrinsic value or artistic excellence. Nevertheless, a
certain amount of decency and splendour is indispensable in both
receiving and sleeping rooms; and though a house really well, that is
beautifully, furnished is of rare occurrence, this is not for want of
serious efforts, nor altogether to be laid to the account of
unwillingness to spend money for such a purpose. Whether the "art of
furnishing" or the desire to have what people require for use in their
houses more becoming and beautiful, be a rising influence or not, it
is certain that the "fancy" or ornamental furniture trade is of large
and increasing importance, corresponding to the increased size and
cost of modern London and country houses, compared with those built
during the reigns of William III. and George IV. Every tradesman who
has the pretension to repair chimney-pots, to whitewash, or paint
house-fronts, ceilings, or offices, writes up the word "decorator," on
his shop-front.


THE QUALITIES REQUIRED IN FURNITURE.

We may consider furniture under two broad divisions, that which is
made to be handled and moved about, and that which is for use but not
meant to be handled or moved. We may add a third division in the
actual fixtures of the house, made by the joiner and meant to be
ornamental fittings or completions to the builder's and carpenter's
work.

Under the first head will be included light tables, chairs, couches,
and other movable objects; under the second, cabinets, book-shelves,
frames, mirrors, and so on; under the third head come flooring,
panelling, window shutters, door-frames, stair-rails, &c.


1. CHAIRS, TABLES, ETC.

The essential points in a well-made chair are comfort, lightness, and
strength. Of course, as men and women are pretty much of the same
proportion all over the world, chairs, of which the seat is about the
height of the lower process of the human knee-joints, must be of the
same height, or but slightly varied, in every country. From the habit
that so many persons have of throwing their whole weight back and, as
we are told, in some countries, of balancing their persons on the back
legs of their chairs and inclining their legs in the direction of the
chimneypiece, there is often an immense strain on the back joints of
chairs. Whether we lean back or swing on them, the junction of the
seats of chairs with the backs is always subject to severe trials; and
on no article of furniture in common use is such good joinery
required. It is worth while to look at the old wall paintings of the
Egyptians, as they are given in Rossellini and the great French book
of the 'Description de l'Egypte,' to see what capital workmanship
those most ancient carpenters bestowed on their chairs. Those of the
best and oldest periods are without connecting bars to the legs before
or behind, all the strength of the construction being centred in the
excellence of the joints of the seat with the back and legs; and in
modern workshops, the highest skill is applied to ensure strength in
these points of junction. If the wood is thoroughly dry, the mortises
and tenons fitting perfectly, and the glue good, the different parts
are so wedded together that the whole structure becomes one piece, as
if nature had made a vegetable growth in that fashion, all the fibres
of which have continuous and perfect contact with each other. If,
however, there is a deficiency in any of these conditions, these
joints fail. If the wood shrinks, or the tenons do not fit the
mortises all through, or the glue is deficient, these various portions
speedily come to pieces. Sofas, couches, and stuffed chairs are so
much more massive in construction that there need be no risk of such a
kind of disintegration.

The members of which a chair is made up may be either turned in the
lathe, or left massive enough to allow of carving on the legs, backs,
or round the framework of the seat. Turned work can be lightly inlaid
with ivory, as that of ancient Egypt, painted, gilt, or mounted
(lightly also) with metal.

The subjects of the carving may be either figures of men, horses,
lions, or the heads and legs of such animals, acanthus leaves, and
arabesques. Many of these ornaments have been used from ancient times,
and revived at various historical periods. For modern rooms the
lightest construction is most in place, and therefore carving should
be compact in composition and delicate in execution, without
prominences or undercutting that would interfere with comfort or be
liable to breakage.

A certain architectural character is given to chairs by cutting
flutings down the legs, or by borrowing other slight details from
architecture. The upholstery of chairs will always be their most
noticeable decoration, and this applies still more to lounging chairs
and couches of all shapes and sizes, as the framework of them is so
much less observable in proportion to their upholstered surfaces.

Tables, lampstands, &c., being generally, though not always, meant to
be moved about, require as light a construction as is consistent with
strength. The surface of all but small tables is beyond the dimensions
of a single plank of wood. The outer and inner portions of a log or
plank are of different fineness of grain, contain varying proportions
of sap, and shrink in different degrees. Single planks of wood,
therefore, can only be exceptionally used for table tops. Generally,
they are made up of portions of planks selected with great care,
grooved on the edges, with a tongue or slice of wood cut the cross way
of the grain, uniting the planks about the middle of their thickness;
the edges are then firmly glued together. If the surface is to be of
wood which can be procured in large pieces of straight or continuous
grain, such as mahogany, the wood is solid throughout; if of some rare
wood or rare figured graining, such as the roots or wens of oak, this
ornamental surface is laid on in thin slices with glue and heavy
pressure. This is known as _veneering_. The surface is sometimes
inlaid with ivory, metal, mother-of-pearl, slices of agate and other
substances, as in the Boulle or marquetry work already alluded to.

The frame of the table is either a deep rail not far within the edge,
or a thick pillar or leg or several legs collected, mortised into a
broad expanding foot and supporting a spreading framework above, to
which the top itself can be fastened, and stretching far enough all
round in the direction of the edges to give a firm support.

The decoration of the top can only be superficial if the table is for
use, and any decoration by carving, piercing, and so on, must be
confined to the framework and the supports. These parts can be, and
have been at all times decorated as the framework of chairs, and by
very much the same kinds of ornament.

To tables of more modern periods, little galleries of pierced work or
of tiny balustrades are sometimes added. They belong to the age of
porcelain collectors, hoops, broad coat-skirts, and tea-parties, and
are intended to save delicate wares from being swept to the ground.
Side tables, and such as are made to support heavy objects, can be
treated with more massive frame work and supports, and the carving and
decorations will be bolder and larger accordingly.


2. CABINETS, ETC.

I will proceed to the second division of furniture, cabinets,
bookcases, and other standing objects, which are more or less
immovable. But shelves and china trays must be placed in secure parts
of the room, if they are not actually fastened to the wall. The former
must be strong to support the great weights laid upon them, and the
supports or framework, which is all that would be seen, may be carved
or decorated with surface or applied metal ornament. On a large scale,
fittings of this kind belong rather to architectural woodwork. China
holders, whether placed on the ground or fixed against a wall, are
properly treated with shelves quaintly shaped on plain and light,
pierced galleries or gilt decorations corresponding with the apparent
lightness of pieces of porcelain. The wood and lac work cabinets of
the Chinese; and the complicated, but not ungraceful, gilt mirror
frames and flourishing acanthus work of the Italians, French, and
Germans, of the last century, seem specially suited for showing off
this gay and fragile material. The collector proper will probably
place his treasures under glass, and with little regard to the
framework of his cases. Here china and china stands are treated only
as decorations.

As to cabinets, they are the most precious, if not the most useful of
all pieces of furniture. They have generally been intended to hold
family treasures, are not required to be moved, and have therefore
been the richest and most decorated objects in the room. Cabinets are
the legitimate descendants of the chests of former days containing
bridal outfits and trinkets, or plate, jewellery, and other valuables.
They were carried from town to country, from grange to castle. About
the beginning of the sixteenth century, the personal habits of great
men became less nomad, and their chests were no longer liable to be
packed and moved away. These receptacles were mounted on stands at
which height the lids could not be lifted, and doors were substituted.
Drawers took the place of shelves or compartments, and every sort of
ingenuity was applied to make these pieces of furniture quaint and
splendid inside and out.

As to shape, it is contrary to their purpose of convenience and
interior capacity, to make cabinets, cupboards, or other receptacles,
with showy and spreading architectural details, such as cornices,
architraves, columns, pediments, and the like. All these parts, which
are laborious and costly in construction, are so many additions to its
size, and make no more room inside to compensate for this expenditure.
Cabinets should, in propriety, be as big and convenient inside as
their size would lead us to expect.

On the other hand, the many fine examples made in the sixteenth and
seventeenth centuries in this country, Holland, Germany, France or
elsewhere, have been generally intended for rooms larger, higher, and
with fewer pieces of furniture in them than those of our modern
houses, not to speak of the massiveness of fireplaces and fittings
with which they were in character. It is their age, and the
connection, which we cannot help tracing, with old houses and bygone
generations which give architectural cabinets an interest now.

In construction, the skill of the cabinet maker will be shown in the
neat and convenient arrangement of drawers of various depths and
sizes, shelves or repositories, so contrived as to turn the entire
internal space to account. The most curious contrivances are often
found in old German, English, and French cabinets, bureaux,
secrÃ©taires, and other varieties of this kind of furniture. Pediments,
capitals of columns, and other parts of architectural fronts are made
to open, and secret drawers stowed away with an ingenuity almost
humorous. It is upon the fronts and stands that the skill of great
masters of the craft has been bestowed. The large wardrobes, or
"armoires," of Boulle are examples of great inventive and designing
power, as well as the marquetry of Riesener and David, and the
chiselled metal-work of Berain, GouthiÃ¨re, and that of many English
artists.

As in past times, and so in our own, it is on cabinets that the real
triumphs of the cabinet maker's art are displayed.


3. FIXED WOODWORK.

Thirdly, the joiner's and cabinet maker's art plays an important part
in the fixed furniture of the house, and the woodwork, such as
flooring, doors and door-frames, panelling, chimneypieces, with the
complementary decorations of hangings, whether tapestry, silk, or the
more humble material of paper.

In this last division of furniture the work is that of joinery. There
is no great demand for constructive strength, as the work is fixed to
walls; but as doors and shutters are swung to and fro continually, and
subject to jars and strains, their stiles and rails, upright and
cross-framing members, as well as the panelling that fills them,
require well-seasoned timber and the most accurate workmanship:
without these conditions the joints open, the panels shrink from the
grooves in which the edges are held, and split, while the frame
itself, if of unseasoned material, 'buckles' or twists, so that the
door or shutter will no longer shut flat in its frame.

Panelling and fireplaces are, however, opportunities for the display
of carving, inlaying, and gilding. The reader has seen carved room
panelling, probably, in many old houses. In some of the municipal
'palaces' in Flanders, e.g. in Bruges, and in the old rooms of the
Louvre in Paris, carved panelling of the utmost grace and perfection,
some of it in groups of life-sized portrait figures, may be studied by
the tourist.

Of work so rich and costly as this wood sculpture, it is perhaps
hopeless to speak with reference to our modern houses, and in
connection with the manufacture of furniture in this country, at least
on any large or general scale of application. Still as such work,
confined to the composition of fireplaces or sideboard backs, is still
sculptured by Italian and French carvers, and has been sent to
Universal Exhibitions of recent years, it must be considered a
possible effort for our great employers of skilled labour.

The panelling of wall surfaces will be divided into larger or smaller
reticulations or framework, with some reference to the size of the
room, that is to say, that very large and lofty rooms will not bear
the smaller subdivision of space and delicate moulding lines which are
so general in panelling of mediÃ¦val or very early Tudor houses, and
which are in keeping on walls of moderate size. Any inlaying or
variety of woods should be used on walls with great discretion.

So far, then, on the general consideration of the work, which it is
the business of the furniture maker to produce. In theory, it is his
object to satisfy daily wants and necessities in the most convenient,
useful, and agreeable way.

The difference between rudeness and refinement in daily habits
consists in putting first order and propriety, then comeliness and
cheerfulness into our homes and habits. There is so much to be borne
and to be done merely that we may live, so many contradictions to
natural inclination meet us on all sides, that we look for repose, and
some moderate satisfaction to the natural desire of the eye, in that
which meets it, and must meet it, so constantly. This satisfaction is
beauty, or some measure of it, or what we have grown to take for
beauty. As the eye is more exercised, the mind more informed, and
becomes a better monitor or corrective to the eye, so we get less
satisfied with much that passes for beauty, and so, on the other hand,
we find it out in objects in which it is commonly or often passed
over.


MANUFACTURE.

A return prepared by the Commissioners for the Paris Exhibition, in
1867, gave the following as the number of manufacturers engaged in
London in "the several branches of the fancy furniture trade."

  Cabinet makers                             812
  Upholsterers                               486
  Carvers and gilders                        342
  French polishers                           142
  Cabinet carvers, inlayers, and liners      108
  Bedstead-makers                             43
  Chair, sofa, and stool-makers              252

Wood and cabinet wares were exported (in 1865) to the value of
289,887_l._, and imported to the value of 128,925_l._[5]

        [5] Cat. Brit. Section Exhibition, 1867, Introduction, p. 61.

The highest efforts of the trade are concentrated in a few large
establishments in London and the great cities, which have their own
cabinet makers, carvers, upholsterers, &c., on their premises. In some
instances, one piece of furniture may pass through the hands of
several branches of the manufacture. I may choose a few names of
makers who presented their works in Paris in 1867 in alphabetical
order, e.g. Messrs. Collinson and Locke, Crace, Dyer and Watts,
Gillow, Herring, Holland, Howard, Hunter, Ingledew, Jackson and
Graham, Morant, Trollope, Wertheimer, Wright and Mansfield. The larger
of these establishments are supplied with steam machinery, and all the
work that can possibly be executed by mechanical agency is prepared by
these engines, leaving only the most costly operations to be executed
by hand.

It is the province of the carpenter to put together simple woodwork;
that which is an actual part of architecture, such as boxes, chests,
benches, seats, shelves, and so forth as require only good material
and neatness of hand in execution. The joiner and cabinet maker
include this amount of skill as a foundation for their
accomplishments, as a sculptor can block out a statue and a painter
grind his colours, work, however, which in ordinary practice is handed
over to assistants or apprentices.

Before discussing the materials and the methods of execution now in
use, it would be well to notice a great change which has taken place
both in the status of the workman, the division of labour, and the
mechanical appliances now at his command.

Down to recent times, joinery and cabinet making were in the hands of
a number of masters in the trade, far greater in comparison to the
pressure of the demand on the part of buyers than is the case at
present. We have a larger society of buyers, a greater demand for the
execution of large orders at a rapid rate, than was the case in former
generations. On the other hand, the trade is gathered up into fewer
master hands. The masters then employed a less amount of labour. They
took in apprentices, many of whom remained for years with them as
assistants, and the establishment was more of a family. It followed,
that all members of this smaller society worked together and took part
in the particular sets of chairs, the tables, cabinets, and so forth,
turned out from their own house. They were, moreover, animated in a
closer and truer degree by the spirit, and adopted the ideas, of a
master who worked with or overlooked and advised them constantly, than
could be the case in our great modern establishments. Again, though,
as I have already said, the old operations by which boards, bars, and
other members of wood construction are joined together, have not
substantially varied since the days of Egyptians and Romans, the
methods of execution have undergone a great change, owing to the
introduction of machinery. The skill and training of the hand of the
workman must necessarily undergo a change as well, whether for the
better or the worse. The workman is relieved from the necessity of
attaining an absolute accuracy in much of the ordinary but essential
work of joints, mortises and other operations which can be produced
with an uniform exactness by mechanical means.

The fact, also, that different engines or lathes can produce at a
prodigious rate certain separate parts of many pieces of furniture,
has made skilled mechanics less universal "all round" men than they
were. If this combination of qualities is to be met with in provincial
towns or villages, there, without doubt, the standard of excellence is
a lower one.

_Materials and Execution._--The woods used for making furniture
besides pines and deals, are birch and beech (used for stuffed
chair-frames, couches, &c.) walnut, letter wood, Spanish and Honduras
mahogany, sycamore, lime, pear, cherry of several kinds, and maple;
ash, English, American, and Hungarian; oak, English, foreign, and
pollard, with pieces cut from wens and sweet cedar. Turners use also
plane, laburnum, yew, holly, and box. More precious woods are also
used in furniture: rose-wood, satin-wood, ebony, and sandal-wood.
Other rare woods are used in inlaying and marquetry.

Some of these materials, mahogany and walnut, which are much in use,
are imported in vast logs, the former sometimes three feet square;
when of very fine grain suited to veneers, worth 1000_l._ or more, per
log.

The woods are stacked in yards, or, in London, where the space cannot
otherwise be had, on platforms resting on the walls of the workshops,
and fully exposed to the weather. Woods are dried after a year, or two
years, according to the size of the log and nature of the wood. Oak is
sometimes kept for eight or more years. When sawn into the scantlings
required, it is further dried by placing the logs and planks in rooms
heated by the waste steam from the engine. An American patented method
of drying is to place a coil of pipes, through which exceedingly cold
water is passed in the drying room, which condenses and carries off
the vapours from the wood exposed to this heat. Some firms have tried
this method, but, I believe, without much success.

Logs are cut up by the engine with three or more perpendicular saws at
once, the teeth being set to the right and left alternately, to open a
passage for the blades. More valuable woods, e.g. mahogany, are cut
into thin plank by an horizontal saw. In this case the teeth are not
bent, but a labourer opens the passage for the blade by lifting the
plank with a wedge. As little waste of the material as possible is
thus secured.

Further cutting up of the material is done by means of circular saws.
Part of the saw rises through a metal table. A moveable bar is firmly
screwed at one, two, or more inches from the blade, and the wood is
pushed by the workman against the saw, keeping one surface against the
fixed bar, so as to secure a straight cut of the thickness required.
Most modern _planing_ is done by a revolving cutter, brought to
bear upon the wood, which is drawn under it on an iron table, with
more or less pressure, according to the quantity to be taken off the
surface. Messrs. Howard have contrived a tube with a blast down it,
which carries the shavings at once to the furnace, otherwise the dust
made by the flying particles of wood would be unendurable.

_Mouldings_ for panelling, cornices, skirtings, &c., are cut by
revolving cutters or chisels, filed to any desired shape and
case-hardened. They are set in a perpendicular axle and cut
horizontally, the wood being firmly pressed against the tool. The
workman can gear the cutter or reverse the action, so as to make a
neat finish to his work.

Formerly all such work was done with a plane, cut to the required
figure, and the finishings of lines of moulding had to be carved with
the hand.

_Mortising_ is done by a revolving boring tool, against which the
wood to be mortised is moved by a gradual action, from side to side,
and backwards and forwards, till the exact depth and width are bored
out; tenons fitting these cavities are cut in another lathe, also by
mechanical action.

_Turning lathes._--The legs of chairs and tables are made in lathes,
the general outline being obtained by turning in the simple form.
Portions of the legs are sometimes squared, and the square faces must
be evenly graduated. These parts are cut as follows: the lathe and the
leg in it are kept at rest, and a revolving tool--in fact, a small
lathe with a perpendicular cutter in it, connected by a leather band
with a spindle overhead--set in motion by the steam-engine. The
workman passes this cutter carefully down the four surfaces of the
portions to be squared, cutting to a given depth all down, but never
losing the angle outlines originally found by the first turning. When
flutings have to be cut down the legs, whether they are round or
square, this is done by using a revolving cutter set with horizontal
action, which passes carefully along at one level, and is geared by
the joiner so as to graduate the width of each fluting, as it
descends, if the diminishing size of the support or leg requires it.

Bars of chairs, edges of shelves, the stretchers (or connecting bars)
under some kinds of tables, are cut into carved or other shapes by an
endless band saw revolving on two rollers. The workman passes his wood
along an iron table against the saw, gearing the former according to
the pattern drawn on the surface.

_Fretwork_ is done with a still finer hair or watch-spring saw, of
which one end can be detached from the holder and passed through a
small hole in the piece of wood where the piercing is to be cut out by
the saw. This could not be done by an endless saw, which can only be
used to shape out edges. The best saws of this description are made by
Perin, in Paris.

Watch-spring saws strained in frames have long been in use. In the
steam-engine it is the wood only that is moved, and as it rests on a
steady table, it gives the workman a great advantage, and should
enable him to shape out his design with a delicacy only attainable
with greater difficulty by the old method.

The process of _mitreing_ pieces of moulding, where they meet at
an angle at a corner, is done by machinery in some houses. In the
works of Messrs. Jackson and Graham, this is done by setting the
pieces in a metal T square. They are carefully cut by hand, and
as each piece is set in a frame geared to the angle required, and
under the hand of an experienced workman, no inaccuracies are likely
to occur. In cabinet-making and joinery of all kinds, the number of
angles round which mouldings have to pass is very great, as anyone
will see who is at the pains to notice the construction of furniture
of the most ordinary kind. Any staring or opening of an oblique joint
is destructive of the effect of such workmanship, as it is of the
strength of the joint which is glued together, and requires absolute
contact of the parts to be joined.

Much work, such as chair rails, table legs, balusters for little
galleries or on a large scale, is turned and cut in the steam lathe by
hand, using steam power only to turn it.

_Joinery._--The pieces of wood thus prepared are made up in many
different combinations. This is the work of the joiner. In the
joiners' shop of Messrs. Jackson and Graham, for instance, several
benches were shown to me occupied by lengths of wall-panelling in
ebony, some of the work being intended to cover the wall of a
staircase; it was therefore framed in sloping lines. Each panel was a
rhomboid, and none of the sides or mouldings were at right angles to
each other. The mouldings had several fine strings, ovaloes, &c., all
specially designed by the architect of the house--as the fittings of
well-furnished houses should be. For these, special cutters had been
made and fitted to the steam-moulding machine. To show the back of the
panelling, the workmen turned it over. Instead of each panel being
held in a groove provided in the stiles and rails, a rebate only has
been cut in the frame, and the panel fits into it from the back (as
the stretcher of a picture fits into a picture-frame), while iron
buttons screwed into the frame pieces hold the panels firmly in their
places. The object of this is to allow for the contraction of the wood
with the alterations of temperature. With some woods, however well
seasoned, this provision is requisite, and it is the more necessary,
when more than one material is employed. In using ebony over large
surfaces, it is found that the lengths required for the continuous
rails cannot be procured free from knots or faults; and particular
kinds of wood (pear and other material) are stained and prepared, to
supplement the ebony in these instances.

The joiners put together panelling, chairs, couches, frames of tables,
shelves, cupboards, and other complex pieces of furniture.

_Upholstery._--Chairs and sofas required to be stuffed are then
handed over to the upholsterer, and the seats and backs are stuffed
with curled horsehair, carefully arranged so as not to wear into
holes. A _French edge_ is given to some stuffed seats by bringing
the edges of several ridges of horsehair together, so inclined towards
the upper edge, that each roll receives support from the others, which
react on the pressure thus brought upon them, like springs. One would
suppose that these edges were maintained by whalebone, like the stocks
in which a past stiff-necked generation suffered so much. Where ribbon
scrolls, tiny bunches of flowers, &c., are carved on the frames and
top rails of chairs and sofa-frames, if these are to be polished only,
the polishing is done before the upholstery. If _parts_ are to be
gilt, or the _whole_ gilt, these operations are postponed till
the upholstery is completed. So also when panelling, sideboards,
bookcases, &c., are to be made up, the moulded lines which can only be
conveniently hand-polished while in lengths, are treated thus before
making up; and there remain only flat panels and surfaces, that can be
evenly rubbed for the final polishing. In upholstered furniture, the
coverings would be greased and stained, if polishing were done over or
in connection with them; but in the case of gilt work, it must be left
in most cases to the last, for fear of dimming or rubbing the gold
during the processes of sewing, nailing, stuffing, &c.

I may remark here, that though arm-chairs, fauteuils, &c., are made in
great London establishments, the manufacture of light chairs on a
large scale is a special branch of the trade, and mostly carried on at
High Wycombe, in the neighbourhood of which town there are extensive
woods of beech, and where land and water carriage is at hand to convey
these productions to London and elsewhere.

_Cabinet-making._--It is by no means easy to lay down the exact
technical boundary between what I have been describing as _joinery_,
and what I am now about to call _cabinet-making_. They are
considered, however, as distinct branches or rather, perhaps,
different operations of the trade; and in such establishments as we
are discussing, the cabinet makers and joiners have their own separate
workshops and benches, and corresponding separate repositories for
storing and drying their woods. Every kind of work is required in
making costly cabinets, bookcases, sideboards, commodes, or by
whatever name we choose to call the beautiful chests, cupboards, and
other artistic receptacles, tables, consoles, brackets, &c., that go
to complete the requirements of our modern reception rooms.

They are seldom made with the quaint or elaborate interior fittings,
such as have been alluded to in older work, but every resource is
brought to bear on the external decoration. Here we come to the arts
brought to bear on the ornamentation of furniture.

Let us begin with carving. Sculpture is the highest or most beautiful
kind of decoration that can be applied to furniture. It can only be
executed by a trained artist. To go no farther back here than the
Italian and French Renaissance furniture, generally made of
walnut-wood, it is the spirited and graceful sculpture that makes its
_first_ great attraction. The Italian carving of this kind is the
most graceful; while that of France by Bachelier and others, and much
that was executed in England and Germany, being, if less graceful,
always spirited and thoroughly decorative. As a general rule,
sculpture so applied is _conventional_ in design and treatment,
that is, we rarely see it, (except, perhaps, occasionally in little
ivory statuettes, and in bas-reliefs,) strictly imitative of nature,
like perfect Greek sculpture. But neither should we find strict
studies from nature on Greek furniture, if we had it, except with the
same limitations. The furniture made by Greco-Roman artists, and
discovered at Pompeii,[6] bears witness to this assertion, such as a
head, a bust, the claws of animals, sculptured on furniture generally
ending in scrolls or leafwork. If a human figure is complete, it bears
no real proportion to objects round it, and so on.

        [6] See also Q. de Quincy, Le Jupiter Olympien.

Excellent wood sculpture used to be executed in England, from the days
of Grinling Gibbon to those of Adam and the Chippendales, suited to
the furniture then in fashion. I wish I could say that our furniture
makers of to-day could easily, or did generally, command such talents.
Ingeniously carved representations of animals and game on sideboards
we sometimes see, but game 'dead' in every sense. If, indeed, Messrs.
Crace, Howard, Jackson and Graham, and other firms could persuade the
Royal Academicians to model for them, those artists would have to give
some material amount of time to the study of how they could so
effectually modify their skill as to suit the requirements and
opportunities of a piece of furniture, these being quite peculiar. The
French are easily our masters in this respect, but even they sacrifice
good qualities proper to this kind of sculpture, in a morbid search
after the softness of nature.

A curious piece of mechanism has been invented, and is in use in most
large London furniture workshops, for _carving by steam_. Besides
boring out and cutting away superfluous material, there is an engine
for making mechanical sculpture in bas-relief, or the round. The wood
is fixed on a metal table, which is moved to and fro and up and down,
so as to come in contact with a revolving cutter held above it. The
wood is then shaped and cut, according as it is elevated or moved.
There are three or four cutters, and one piece of wood may be placed
under each. Under the middle cutter, replaced by a dummy tool that
does not really cut, the workman places his cast or model, and makes
the dummy cutter pass over every undulation of its surface. The two or
three cutters on either side cut the corresponding blocks exactly to
the same depths and undulations as are followed by the blunt tool. It
is a _copying machine_. That such copies, though they may pass
muster, will ever have the charm of original carving, the reader shall
not be asked to believe.

Certain elaborate methods of decorating and finishing woodwork must
now be described, viz. those known as _inlaying_ and _marquetry_.
These two processes are distinct, but marquetry furniture has often
portions decorated with inlaying, as also carved ornaments and
decorations of beaten, cast, or chiselled metal-work. This last
addition is not generally of the same importance in our modern English
woodwork that it was a century ago, and I will describe the former
methods first.

_Inlaying_ means the insertion of pieces of more costly wood, stone,
small discs, or carved pieces of ivory, into a less valuable material.
The process is as old as any manufacture in wood working of which we
possess records. Beautiful plates or blocks of ivory can be seen in
the Assyrian gallery of the British museum, found at Nineveh by Mr.
Layard. They are deeply cut with lotus and other leaf decorations,
figures and hieroglyphics, and most of them have an Egyptian
character. The ivory figures, too, have been inlaid and filled up
with vitrified material. Remains of these decorations are still
discernible, and the thickness of many of these pieces of ivory shows
that they have been sunk bodily into woodwork of a solid character.

No such work as this can be pointed out in our London workshops, but
patterns and arabesques, both of wood and ivory, are occasionally let
into solid beds of wood so deeply, as to be actually mortised into the
main body of the structure. This is done both by our own makers and by
the French cabinet maker, Henri Fourdinois, a prize piece of whose
make was bought for the South Kensington museum. It is not uncommon to
insert pieces of lapis lazuli, bloodstone, and precious marbles into
centres of carved woodwork, and I may call attention to the use of
plates, medallions and cameos of Wedgwood, or SÃ¨vres ware, which were
frequently inlaid by Chippendale, and by the great French furniture
makers, or _Ã©bÃ©nistes_, of the last century. These are used in the
modern satin-wood furniture of Messrs. Wright and Mansfield, and I
have lately seen a coarser material used, viz. bas-reliefs in
_stoneware_, imitations of the _gris de Flandres_, by Messrs. Doulton.
These last, however, may be said to be rather panels set in frames,
than pieces let into cavities in wood.

_Veneering and Marquetry._--An effective method of ornamenting
woodwork by the application to the _surface_ of other woods is what is
known as _veneering_ and _marquetry_. The surface is in both cases
covered with a thin layer of other woods, fastened on with glue and by
strong pressure. Some of the panelling, table tops, and other joiner's
work already described, is clothed with a thin slice of more valuable
wood. This is called _veneering_. Woods such as ebony, tuya,
satin-wood, palm, hare-wood, and a number more, are only to be had in
small scantlings, logs a few feet long, and six or seven inches wide.
Other woods, of which the grain is most beautifully marked, are cut
from roots, wens, and other excrescences of the trees, to which they
belong, and are only found occasionally, and in lumps of no great
size. The contortions of the grain, which make them so valuable and
beautiful, are owing to peculiar conditions of growth. In all these
cases an inch plank of wood has to be cut into very thin slices,
twelve being cut with a saw, or from eighteen to twenty-two if it is
cut with a knife, as in that case no material is wasted by the opening
made by a saw. These slices are laid on the surface of well-seasoned
wood, and in the workshops of our great manufacturers will be seen a
metal table or bed, prepared expressly for the process of veneering.

Supposing the object to be veneered to be a large surface--a number of
panels, or the top of a table of ebony, for instance--the substance of
the table may be Honduras mahogany. The wood has been carefully
seasoned, and the top grooved, tongued, and firmly glued up to the
required form. The ebony surface is also carefully fitted together and
glued on paper, the surface being left rough, so that the glue may
have a firm hold on the fibre of the grain. A corresponding roughness
is produced on the upper surface of the mahogany, which is then laid
on the metal bed. Glue, perfectly fluid and hot, is now rapidly
brushed over the entire surface, and the thin veneer top is laid upon
it, and firmly pressed down by several workmen, who then carefully go
over the whole with hammers having broad, flat heads; the object of
this being to flatten any apparent thicknesses of glue or bubbles of
air which would interfere with the perfect contact of the two surfaces
of wood. The whole is then placed under a caul or frame that touches
it all over, and a number of strong bars are screwed down till the
greater part of the glue has been pressed out. The complete union of
the surfaces of the woods is effected not so much by the quantity of
glue as by the absolute exclusion of the air, and this can only be
done by pressure. The whole metal bed or frame in which the veneering
is performed is heated by steam, or by gas-burners, where steam cannot
be applied. The wood is left for twenty-four or thirty hours, till the
glue has been completely set and hardened. The caul or frame is then
removed, the paper used to keep the thin veneer together before gluing
is scraped off, and the work of finishing and French polishing takes
place. French polish, or careful wax polish, has the effect of keeping
out air and damp, which latter might soften the glue and disintegrate
the surface veneer. It is to be observed, that such wood as the finest
French or Italian walnut is often veneered on mahogany, for it lasts
better in this condition than if it was solid; large surfaces and
thicknesses of walnut being difficult to procure without faults.
Walnut veneers are applied in greater thicknesses than ebony; and if
the surfaces to which they are applied are curved, cauls, or shaped
pieces of wood made to fit them, are screwed down and held by numerous
wooden vices, as in the method already described.

_Marquetry_ is the application of veneer made of different woods,
ivory, &c., composed like a mosaic or painting executed in coloured
woods. This kind of decoration is of ancient use, was much in vogue
during the Renaissance of the fifteenth and sixteenth centuries, and
was carried to a great pitch of perfection in France during the
seventeenth and eighteenth. It is still practised, and the process may
be seen in full activity in the workshops of our modern furniture
makers. In cutting out the forms required for marquetry decoration,
one, two, or more thicknesses of thin wood are gummed or pasted
together, according to the pattern required. In many fine pieces of
marquetry there are, as in the case of a cabinet or table, portions of
the surface entirely occupied by quiet reticulated patterns. As in
these cases the same pattern often recurs, several thicknesses of wood
can be laid together, and are then firmly fixed in a vice, having
pasted over them a piece of paper on which the pattern is drawn. A
small hole is bored where it will not interfere with the design, and
the end of a thin watch-spring saw is passed through, and then
re-attached to the frame that strains it out in working order. With
this in his hand, the workman carefully traces the outlines of his
drawing, which the tenuity of the saw-blade allows the tool to follow
into every curve and angle. The thicknesses are then separated with
the blade of a knife, and the slices become alternately pattern and
ground, so that a set of patterns and a set of matrices of each wood
are ready for use, and can be applied either on different parts of the
same, or on two separate pieces of furniture. If a flower or other
ornament is required which will not be repeated, two thicknesses only
will be cut together. It is necessary that the same action of the saw
should cut out the pattern and the ground in the two woods required,
so that they may fit exactly.

When all the portions of the design are cut out, they are pasted on
paper, and can be fitted together like mosaic. A little sawdust from
the woods used, and a very small quantity of glue, join the edges and
fill up the fine openings made by the saw; and in this way the whole
surface of the marquetry is laid down on paper. In the case of
flowers, heads, architectural or other designs, some slight additions,
either of lines to indicate stalks, leaf-fibre, or the features of the
face, are made with a graver, and stained; or gradations of a brown
colour are given, in the case of white or light-tinted wood, by
partial burning. It was formerly the custom to burn with a hot iron,
but a more delicate tint is given by using hot sand, and this is the
best method of tinting beech, lime, holly, box, maple, or other woods
which are nearly white. There remains nothing but to rough the surface
of the furniture, and to lay down the marquetry on it, precisely as in
the case of plain veneering. When the glue is dry and hard, the
pressure is taken off, the paper which is on the outer surface is
scraped away, and the whole rubbed down to a fine surface and French
polished. The most beautiful work of this description was made in
France by Riesener and David, during the reigns of Louis XV. and Louis
XVI. Besides graceful and delicate _design_, which these artists
(for such they were) thoroughly understood, the beauty of their work
owes much to their charming feeling for colour. Both used light woods,
such as maple, holly, box, lime, &c., and laid brown woods, such as
laburnum and walnut, on this light ground. Sometimes architectural
compositions in the manner of Pannini, a favourite Roman painter of
the day, were designed over the doors or flaps of secrÃ©taires and
cabinets, or busts, medallions, baskets of roses, &c. The charm of the
work is the grace and repose with which these simple decorations are
laid on. Compare some of the work of Riesener and David, on the
cabinet doors in the collection of Sir Richard Wallace, with the
glaring contrasts, the gaudy, often discordant colouring, and the
crowded compositions of modern marquetry, at least of most of it.
There is a tenderness of treatment, a grace and harmony of colour and
arrangement throughout the former, which is wholly wanting, and which
no lapse of time will add to the latter. Though these criticisms are
not meant to be applied to the products of the leading houses now
under review, the reader who has taken an observant stroll amongst the
furniture of Sir Richard Wallace, at Bethnal Green, will find abundant
contrasts as he walks along the streets of London.

In order to illustrate my remarks on the processes of colouring woods
by burning or etching, I may point to a large writing bureau, or
secrÃ©taire, belonging to Sir Richard Wallace, made by Riesener, in
1769 (and signed), for Stanislaus, king of Poland. It is decorated
partly with reticulated pattern work, partly with the royal cipher in
medallions, and with other medallions containing emblematic figures,
such as a carrier pigeon, a cock, the emblem of vigilance, or the head
of a girl placing her finger on her lips, an emblem of silence. All
these medallion figures are broadly drawn, the very slightest and most
delicate tint only being added to represent shading, while the drawing
is a single line lightly pencilled.

The materials used in the best marquetry are lime, holly, box, maple,
beech, poplar, for white; pear, laburnum, palm (cut across the grain),
lignum vitÃ¦, walnut, teak, partridge-wood, for brown; wood called in
the trade fustic, satin-wood, for yellow; tulip, purple-wood, amboyna,
mahogany, thuya, log-wood, cam-wood, and varieties of these woods, for
red; ebony for black, or stained wood. Greens and blues are also
stained with metallic dyes. The finest of the old work may be called
studies in brown and white, and the red woods are used sparingly; the
dyed woods still more so, nor can they be said ever to be really
effective.

As an example of great mechanical skill in a modern piece of very
difficult execution, I might call attention to Messrs. Jackson and
Graham's elaborate cabinet of marquetry, in patterns of Oriental
character, after designs by the late Mr. Owen Jones (sent to the
Vienna Exhibition by Messrs. Jackson and Graham). It had an
architectural front, with detached columns and groups of architectural
mouldings, some of them put together with the lines of moulding in
woods of contrasted hue, an element of ornamentation that took from
the unity and completeness of cap or corona mouldings. The little
columns of an inch and a half diameter were entirely covered with
reticulated pattern in different woods. As the shafts were tapering,
so the reticulated patterns had to be graduated in size from top to
bottom. This was a feat of most difficult execution, nor was it the
only difficulty in this portion of the design. The marquetry in the
instance of these columns had to be wrapped round each circular shaft;
and each edge, therefore, of every portion of pattern and groundwork
had to be sawn out with bevelled edges, so that when rolled, the inner
edges might meet and the outer edges remain in contact, which would
not be so, were they not bevelled: the contrary would happen in that
case, and the outer edges would start in sunder. These columns were
two feet and some inches high, and the little reticulations of pattern
recurred many dozens of times. The conditions of which I speak had to
be carefully observed in the case of each. The pattern, too, was
graduated, as above stated, so that they had to be sawn out by
separate cuttings--a most laborious and costly operation.

We miss in the great English houses one of the most costly and
beautiful elements in the adornment of furniture, and that is, the
fine moulded and chiselled bronze work, always gilt, which enters so
largely into the decoration of fine old French marquetry. The English
furniture makers of a century ago were not so behindhand, and old
carriages had door-handles, and furniture had mounts of gilt bronze.
Probably the French were always superior to us in this kind of skill.
They still produce good work of this class, cast and afterwards
cleaned and tooled with the chisel, but it is not equal to the work of
the same description by GouthiÃ¨re, and the famous _ciseleurs_ of
Paris in the last century.

I must not pass over in silence a beautiful kind of furniture which
was in fashion a century since, and has been revived by Messrs. Wright
and Mansfield, and other firms, viz. satin-wood furniture. In the time
of Chippendale, Sheraton, Lock, and other great cabinet makers,
contemporaries of the French artists Riesener, GouthiÃ¨re, and David,
satin-wood was imported from India. It was made up by veneering, and
was decorated with medallions, some of marquetry, some of Wedgwood
ware, after the model of the French inlaying of SÃ¨vres porcelain
plaques, and in some instances painted with miniature scenes like the
Vernis Martin, called after a French decorator of the name of Martin.
Old examples of satin-wood furniture, such as tables, bookcases,
chests of drawers, &c., are not uncommon, decorated in one or more of
these methods. Cipriani and Angelica Kauffmann were employed amongst
many others in painting cameo medallions, busts, Cupids and so forth
for satin-wood furniture. Messrs. Wright and Mansfield have executed
much of this work, and sent a cabinet of large size to the Paris
Exhibition of 1867, decorated with medallions, swags, ribbons, &c.,
partly in marquetry of coloured woods, partly in plates of Wedgwood
ware. The piece is further set off by carved and gilt portions, not,
however, sufficiently attractive to add greatly to the effect of the
whole cabinet, which is gay, cheerful, of beautiful hue, and excellent
workmanship. It is in the South Kensington Museum.

Allusion has been made to the furniture of Boulle. It began to be made
somewhere about 1660, and was perhaps the earliest start taken in the
more modern manufacture of sumptuous furniture. I have already called
it a great advance and improvement, rather than an absolutely new
invention, for pieces are found of a date too early to have been the
actual work of Boulle. When the tortoiseshell is dark and rich in hue,
the brass of a good golden yellow, and the designs carefully drawn,
Boulle work seems to equal in splendour, though not in preciousness,
the gold and silver furniture of the ancients, and the inlaid work of
agates, crystals, amethysts, &c., with mounts of ivory and silver made
in Florence in the sixteenth century.

Boulle work is made occasionally by French and other foreign houses,
and by Wertheimer of Bond street, but it is costly, and the rich
relieved portions, such as the hinge and lock mounts, the salient
medallions, masks, &c., set in central points of the composition, are
either copies or imitations of old work. They lack the freshness,
vigour, and spirit of the old French metallurgy.

A spurious kind of Boulle is made with a composition in place of the
tortoiseshell.

_Parquet floors_ are made by Messrs. Howard as follows: Slices of
oak, varied sometimes with mahogany, walnut, and imitation ebony, are
laid out and put together on a board. If rings, circles or other
figures are introduced, these portions, patterns, and cavities as well
as angular pieces are cut in the machine. The thickness of these
pieces is a quarter of an inch. They are then laid on three
thicknesses of pine, the grain of each thickness being laid crosswise
to the one below, so as to keep the wood above from warping and
opening. These are glued together, and kept for twenty-four hours
under an hydraulic press. It is, in fact, coarse marquetry, and the
whole is laid down over a rough deal floor. Messrs. Howard also glue
up their quarter inch hardwoods without a pine backing, and lay them
down with glue and fine brads on old deal floors, a less expensive
method, and which can be adopted without raising the level of an old
floor.

It is remarkable that English cabinet makers should so rarely make
these floors, or architects lay them down in rooms of modern houses.
The French, Germans of all states, Swiss, Belgians, in short most
continental nations have these floors, and Swiss and Belgian flooring
is imported into England. That of the Belgian joiners is in large
pieces four feet or so square, of seasoned wood, moderate in price,
and easily laid down.

In this country, our costly modern houses are barely provided with a
border of a foot or so round the edges of the reception rooms. Even
that is but an exceptional practice. Yet oak flooring is not a costly
addition to important rooms, while the habit of keeping floors always
covered with Brussels carpet tacked down is not the cleanest
imaginable.

Another application of veneered wood practised by Messrs. Howard is
called by them "_wood tapestry_." Very thin slices are arranged
geometrically in large patterns, and fastened with glue on staircase
and passage walls, or made into dado panelling to the room, in this
case capped by mouldings.

An ingenious method of inlaying thin veneers on flat surfaces of wood
by machinery has been patented by the same firm. Veneers or slices of
wood about the thickness of coarse brown paper are glued on a board,
e.g. a table top. A design punched out in zinc, of a thickness
somewhat greater than that of the veneer, is laid over it, and the
board is then placed under a heavy roller. The zinc is forced into the
surface of the board by the roller to about the thickness of the
veneer. A plane cleans off the rest of the veneer, leaving the portion
only that answers to the zinc pattern, thus forced into the surface of
the board. If soaked, the grain of the wood would push up the thin
veneer, no doubt, but this is no greater risk than that to which all
marquetry is exposed.

Neither of these inventions have as yet been carried beyond the
simplest disposition of arrangement. What can be done in either method
remains to be shown.

All the woodwork passed under review thus far in joinery and
cabinet-work, is of _hard_ woods. Much, however, of our modern
furniture is of a less valuable description, and is made of pine,
American birch, Hungarian and other ash. Pitch-pine, an exceedingly
hard wood, difficult to dry, and with a disagreeable propensity to
crack if not very well seasoned, is also used, and a beautiful
material it is. Some small quantity of bedroom furniture in beech,
oak, and ash is made in the workshops that I have been describing. As
a general rule, however, this manufacture of soft woods is a separate
branch of the trade. To see soft wood, such as pine, made up into
admirable bedroom furniture, and French polished till the grain of it
shows much of the delicacy and agreeableness of satin-wood, we should
pay a visit to the works of Messrs. Dyer and Watts, in Islington, and
to other houses that occupy their time exclusively in work of this
kind. It is clean, cheerful, and, by comparison, cheap; is ornamented
(in the works of Messrs. Dyer and Watts) with neat lines of red, grey,
and black, some of the lines imitative of inlaid wood. It is popular,
and if we proceed from the workshops of Messrs. Graham, Holland, and
others, to their showrooms and warehouses, we shall find this deal
furniture for sale, though they do not profess to make any of it. Less
costly pine-wood furniture is painted green, or white, or in imitation
of other woods.

The surface of woodwork, if the woods are valuable, is finished by
_French polishing_. A solution of shell-lac is put on a rolled
woollen rubber, which is then covered with a linen rag, on which the
polisher puts a drop of linseed oil. He rubs this solution evenly over
the entire surface of the wood as it passes through the fibre of the
linen, smooth action being secured by the oil. It is laid on in
successive fine coats till a glossy surface is obtained which is air
and water-proof. For fine work the surface should not be so glossy as
to look like japan work. French polishing preserves woods liable to
split, such as oak, from the too rapid action of the air.

_Graining_ is an imitation of oak or other woods. A light colour,
chrome yellow, and white, is first laid on, and glazed over with
brown. While still wet, the brown is combed with elastic square
teethed combs to give the appearance of graining. Larger veins are
wiped out by the thumb and a piece of rag. All sorts of woods are thus
imitated, and the work when dry is varnished over. Independently of
any skill or deceptiveness, this broken painted surface looks
effective and lasts long.

Of the propriety of such a decoration there are many doubts, for the
discussion of which there is not space here. Marble graining has long
been represented in Italy, e.g. in the loggia of Raphael in the
Vatican. But in that particular instance, the painting is a
_representation_, not an _imitation_. Wood graining is performed in
all countries, and such imitations seem to have been practised by the
ancients.

Mr. Norman Shaw is now exhibiting in Exhibition road examples of woods
with fine grain stained green, red, and other colours, and French
polished, the grain showing as if the woods were naturally of those
hues.

For inexhaustible resource in tinting, polishing, and decorating wood
surfaces, we shall have to learn from the Japanese, from whom probably
the famous Vernis Martin was first borrowed in the last century. Much
imitation lac-japanning was executed in this country during the latter
years of the century. This work is still made in Birmingham. Pieces of
mother-o'-pearl are glued on wood and the intervening surface, covered
with lac varnish which is rubbed smooth, coat after coat, with pumice
and water, till the surface of the inlaid pearl shell is reached, and
the whole ground to a glassy polish.


LONDON FACTORIES.

The number of hands employed in large cabinet-making and furnishing
establishments is very considerable. Not only are the workshops well
provided with joiners, cabinet makers, and turners, but also with
upholsterers, cutters-out and workwomen, stuffing, tacking on or
sewing on the covers of chairs, sofas, &c. Indeed, it is no uncommon
occurrence for the entire furniture of royal palaces and yachts to be
ordered from one of these firms by the courts of foreign potentates in
every corner of the world. Chairs, tables, sideboards, &c., were made
lately at Messrs. Holland's for a steam yacht of the Emperor of
Austria; while Messrs. Jackson and Graham have been furnishing the
palace of the Khedive at Grand Cairo.

To execute, with certainty and promptitude, orders such as these, both
premises, plant (such as wood and machinery), and the command of
first-rate hands, must be abundant. Painters, gilders, carpenters,
paperers, and a miscellaneous assistant staff are required to pioneer
the way for the more costly work, or to make all good behind it. The
firm of Jackson and Graham, for instance, employs from 600 to 1000
hands, according to the time of the year or the pressure of orders;
and pays out close upon 2000_l._ per week as wages, when all these
hands are in full work; and to highly skilled craftsmen (independently
of designers), occupied on the production of the most costly kind of
furniture, 60_l._ to 230_l._ per week. The Howards employ from 150 to
200 hands on cabinet making and joinery alone. It is the variety and
comprehensiveness of these operations, that is so profitable as a
speculation. Such a business requires, it need hardly be said, a large
capital, and must be liable to fluctuations.


THE PAST AND THE FUTURE.

A few words must be given to a retrospect of the state of this branch
of the national industry, and to its prospects. If we look back
twenty-five years to the furniture exhibited in London in 1851, the
improvement of the present time seems incredible.

We may take that Exhibition, the first of these modern displays of all
sorts of products of labour, as a point of departure for our review.

In 1851, the Commissioners directed that a complete report should be
drawn up on the subject of the decorative treatment of manufactures of
all kinds, including the particular class of objects under discussion.
The author of this report calls attention to what should be the first
consideration, in the construction of objects for daily and personal
use. From the continual presence of these things, "defects overlooked
at first, or disregarded for some showy excellence, grow into great
grievances, when, having become an offence, the annoyance daily
increases. Here at least utility should be the first object, and as
simplicity rarely offends, that ornament which is the most simple in
style will be the most likely to give lasting satisfaction."[7] Yet on
examining the furniture on the English side, the reporter could not
but notice, how rarely this very obvious consideration had been
attended to. "The ornament of such works on the English side consists
largely of _imitative_ carving." Ornaments consisting of flowers,
garlands of massive size and absolute relief, were applied
indiscriminately to bedsteads, sideboards, bookcases, pier-glasses,
&c., without any principle of selection or accommodation. "The laws of
ornament were as completely set aside as those of use and convenience.
Many of these works, instead of being useful, would require _a rail
to keep off the household_."

        [7] Supplementary Report, chap. xxx.

These strictures were far from being applicable to the entire British
Exhibition of this class of work. One or two notable exceptions may be
quoted, such as a bookcase carved in oak, exhibited by Mr. Crace,
bought by the Commissioners and added to the Kensington collections.
This and a few other works "are particularly to be commended for their
sound constructive treatment, and for the very judicious manner in
which ornament is made subservient to it. The metal-work is also
excellent, and the brass fittings of the panels of the bookcase
deserve to be studied, both for the manner in which they have been put
together and for their graceful lines."

Four years later, in 1855, in the Paris Exhibition, our furniture and
woodwork had made a stride forward, which was still more marked in the
London Exhibition of 1862. By that time, our leading houses had
appreciated the necessity of obtaining talented designers and foremen,
and in many instances they had employed the first architects of the
day to give them drawings. The result was a great progress. While the
French, indeed, continued to produce very fine pieces, some on the
best models, or rather after the principles of the best periods of the
Renaissance, our own cabinet makers had run far on in the same
direction and in many others, for the mediÃ¦val feeling had still a
strong hold on the taste of English architects and their patrons.

The greatest change, however, was that which the Paris exhibition of
1867 brought to light. Fifteen full years had passed, since public
attention had been called to any careful comparison between the state
of our furniture and the decorations of the interiors of our houses,
with those of other countries, and the advance was incalculably
greater on the part of this country than on that of the other
competing nations.

It is worth remarking, that in three great comparative Exhibitions,
and particularly in that of 1867, national tastes and peculiarities
seemed to have been so completely pared away, that it became difficult
to keep the productions of the North and West of Europe from those of
the South or the East, distinct in one's mind. Each nation followed
the fashion of the works that had obtained the best prizes at former
Exhibitions.

For the present, French Renaissance designs in woodwork, and the
produce of the looms of Lyons in hangings, serve to give the key to
the school of domestic and industrial art in this country. If we look
at the richest and most costly productions that have been exhibited,
and carried off prizes at the International Exhibitions of late years
(and we have no other standard of easy comparison), it will be found
that French cabinets, tables, and chairs have served as models to the
successful competitors. Indeed, the most successful of such pieces of
furniture are actually designed by French artists in some of our
leading firms. There is a decided English type in the satin-wood
furniture of Messrs. Wright and Mansfield, and there is some
invention, though not always happy, about our designers of mediÃ¦val
furniture. These productions are, however, too apt to be heavy and
ecclesiastical, to follow rather the types of stone constructions, and
the teachings of the admirable plates of Viollet-le-duc, than the
lighter work, inaugurated, not without power and success, by Pugin.
There is a company of artists, Morris and Co., who have combined
painting and woodwork, and produced excellent results; but they have
had few followers, or rather few successful followers. I cannot but
mention with honourable commendation the Royal School of Art
needlework, as a subsidiary branch of furniture art.

So far as to the past. With regard to the future some few remarks may
not be out of place: on the excellence of workmanship, the propriety
of design, and the beauty of decoration.

The altered conditions of a trade such as that of the cabinet maker,
which combines the useful with the agreeable, comely, and beautiful,
in its productions, have been alluded to already. This change must
seriously affect the accomplishments of the workman. Instead of
working under and with his master, he is become one of a regiment of
officials. He cannot identify himself with the entire work of which he
only executes members interchangeable with other members, all
mechanically alike. Again, mortises, tenons, dovetails, and joinery of
all sorts, no longer demand from hand-work the accuracy, neatness, and
perfection of former days. These operations are done for him.
Occasionally he supplements the work of the engine. Like a player who
only plays music occasionally, we cannot expect him to retain all the
fineness of his hand in perfection.

Is the modern workman, then, the equal of those of sixty years since,
whose productions stand so well to this day, because of this
perfection of manual dexterity? It will be difficult to maintain that
he is, but it would be most unjust to deny either that the best
workmanship can be turned out, or that it is turned out, of our great
establishments. This is the work of the most choice and accomplished
hands. In smaller London houses, and in the furniture which we find in
the trade generally, the workmanship is inferior, relatively, to that
of the former period.

The introduction of machinery, however, is a fact, and its effects on
manual skill must be accepted as a necessity. Nor must we pass over
the further fact, that if the modern joiner is not the equal of the
journeymen of Chippendale, he can _do more_. He has powers at command,
and can carry into execution quantities, beyond the reach of
half-a-dozen, perhaps a score of his predecessors. The consumer ought
to reap advantages from this latter fact which he has failed hitherto
to get, as shall be explained presently.

This brings me to the consideration of the proprieties of design, and
the beauty of decoration of our present furniture. If workmanship is
affected by altered conditions of the manufacture, so also is design,
that union of effective and suitable decoration with the required
convenience of each piece of furniture, which may be called _style_.

The artist, as regards his productions or style, is fashioned partly
by what he thinks and loves, partly by his materials and his tools.
With some materials he can do little, for want of tools and
appliances. As regards material, wood remains what it always has been,
but the steam-engine supplies an absolutely new set of tools. What has
been done with them? The impressed marquetry has been mentioned, but
as yet nothing really new has been done by the use of machinery. Thin
veneers which might be cut out with scissors, as if one were cutting
paper in inexhaustible fulness and variety, are restricted, in this
impressed marquetry, to such as can be copied in the coarse material,
zinc, which has to be punched or sawn out for the manufacture. Then
again we have the carving or copying machine. At present nothing more
is done with it than to copy, and to copy somewhat clumsily, in
duplicate or in large numbers, that which has first been carved or
modelled by hand. It would be premature to decide, that with so
powerful a tool in his hand, an accomplished artist trained to use it,
could not produce real and rapid sculpture. But no such artist has yet
stepped on the stage, and it can only be an artist who can put the
matter to a proof.

In following the style and ornamentation of former periods, our new
machinery is in no sense a help to us. The man who cuts out his
material for a Sheraton chair _felt_ what he was going to carve upon,
chose his pieces, arranged the grain, and the spare material just as
he would require it, with careful reference to the use of his carving
tools from first to last. _The pace_, too, required in executing
orders was then more deliberate; costly and elaborate plant and
machinery not being required, provincial workmen of admirable skill
were to be found in many towns. There is no royal process by which we
can put a log of wood into one end of an engine, and find a chair, a
table, or a cabinet at the other. What steam machinery does for us is
to perform with certainty, and with immense rapidity, the simple
operations of sawing, planing, boring, and turning. It is by turnery
that ornamentation is done in the engine. Any length of moulded edges
can be soon turned out, any amount of the parts of panelling, of
turned rails, and of ornaments turned on flat surfaces pressed on the
cutting tool, together with the piercing of fretwork and curved and
shaped edges to boards. The saw being a fixture in this instance, is
an advantage, but machine turnery is not rich in resources. The tool
itself is filed laboriously to the mould required, and the wood merely
pressed against it. When the wood revolves (as in the old lathe), the
turner, with the simple edge of his chisel or his gouge, was the
master of an endless variety of ornament limited only by his fancy or
skill of hand.

It is nevertheless in the turnery and the fret-cutting machinery, that
a furniture artist must find the elements of a style. The man of
genius, the poet and maker, who can throw himself into these elements,
will do wonders with them. The lathe is as old as history. During the
sixteenth, seventeenth, and eighteenth centuries, turned wood
furniture was made in considerable quantities in this country, in
Italy, and in the Indian possessions of the Portuguese. All the
furniture of Arabs, Moors, and Turks springs from the lathe and the
moulding plane; the tables and stools, the ingenious reticulation of
Cairene geometrical panelling, the screens of woodwork so effective in
the queen of Arab cities and in Damascus are derived from these humble
sources.

To surface ornament of marquetry, occasional carved insertions can be
added. But light, neat, and elegant woodwork, panelling, bookcases,
cabinets, dressers, chairs, and tables, can be turned out without
these additions, and the variety might be endless.

Carved acanthus foliage, bulging legs and surfaces, artistic carving
and marquetry, and chiselled metal-mountings must be the work of
trained sculptors. The engine gives them no real help. To design, that
is invent (not to copy), carving and marquetry that will bear
comparison with the products of Riesener, and of the school of
Gibbons, is not to be done by command of appliances or skilful
workmanship _only_. The artist who is thoroughly at home in designs of
this kind, is the pupil or descendant of masters whose traditions are
well established:

    "Fortes creantur fortibus."

But neat furniture, unornamented by hand-work, ought to be turned out
of the engine-room, the perfection of lightness, convenience, and
strength. And here the buyer will look for the advantage of
_cheapness_. We do not find that our large makers supply well-made
machine furniture _cheap_. As a broad rule, prices seem to be
calculated on _what a man would do_, and work done in the machine is
priced, as if a man had made it by hand. In point of fact, five or six
men's work is done in the same time, and the cost of wages charged on
articles so made, will leave a disproportioned profit, notwithstanding
the expense of setting up and maintaining the steam plant.

Decorative furniture can never be had at a cheap rate.

A word, in conclusion, as to the arts which are necessarily pressed
into the service of furniture, and their prospects of the future.

These "sumptuary" arts have been spoken of in these pages as a revival
in furniture and _style_, as dead. The disorders that culminated
in the French revolution cut off our present European thoughts, or at
least our manners and customs, from the past.

We are now trying to revivify past traditions. The furniture makers
have made extraordinary exertions in this direction. How will it be in
the coming years?

Some critics are of opinion that "art manufacture" is a delusion, and
that, if our academicians were equal to the ancient Greeks, we should
not find that rich buyers would care about the shapes of their chairs
(if comfortable), the colours of their walls, and so forth--a singular
delusion. If Phidias, Michael Angelo, and Raphael exhibited at
Burlington House, their pupils and followers would overflow with good
work in various degrees of elaboration. We should find it in our
churches, houses, seats, carriages, and the rest. This is what
_did_ happen when the great artists were flourishing. Ugliness
and vulgarity were not endurable anywhere. Mentor expressed himself in
drinking cups, Cellini in brooches, Holbein in daggers, Michael Angelo
in a candlestick, Raphael culminated in a church banner. The art that
finds its utterances on knobs, or handles, or drawer fronts, is
restricted certainly, because the object is of awkward shape or
surface, is to be handled and used, and is only a part of something
larger. Nevertheless the street of tripods in Athens, the front of the
_biga_ in the Vatican, were "occasions" on which good sculptors
did the best that those occasions allowed of. Four fine silver images,
representing four great provincial capitals, in the Blacas Collection
(now to be seen in the British Museum), were perhaps the ends of the
poles of a Sedan chair.

Objects of this kind, though fragmentary, or slightly worked out, or
combined in some grotesque but graceful fashion, with a piece of leaf
or stalk, are the easy results of long years of mental and manual
training.

The workman artist, therefore, though his productions may not be
thought suitable for the Academy walls, is a child of the same school,
as that which brings forth such portents as Phidias, Praxiteles,
Michael Angelo, and Leonardo, not to speak of our Royal Academicians.

Artists who are "specialists," like Giovanni da Udine, will continue
to do special things only, but those admirably. Where the arts
flourish, there will be a large school that includes half a nation,
artists of all ranges of education, refinement, and knowledge. Some
will sculpture figures for the temple, others will be of the rank of
workmen. Vasari has given full details of the sumptuous furniture
which was executed by the sixteenth century Academicians of Florence.

How are we to procure such teachings? This was the question which
Colbert put to himself in the reign of Louis XIV. He resolved it, by
getting masters and teachers of every kind of sumptuary art from
Italy. The result has been to give the French nation a lead in this
kind of industry, that holds good even amidst the ruin of old
traditions, at this day.

The Kensington schools, and those on the same pattern throughout the
country, are efforts made by the Government to meet the wants of our
manufacturers. They are inelastic, and it is too soon to judge of the
work they are likely to do hereafter. The only great error in such
education would be to train scholars to be "ornamentalists," i.e.
_to teach them conventional art_.

Art is conventional in connection with architecture and furniture,
because in most instances this is all that would be proper or look
well. A good modeller, draughtsman, or carver, would become
conventional just as occasion required, but with no abstract desire
for ugliness or the grotesque. That artists should be generally well
educated and good scholars, and that the profession should possess
knowledge and refinement, is of more importance than most people
suppose. This kind of refinement lay at the root of the universality
of accomplishments of the sixteenth century artists.

Lastly, it is not enough that the profession only should be educated,
so as to supply the manufacturer with designs. It is the rich that
must be taught as well. We are neither Italians nor Frenchmen, and,
indeed, speaking generally, we have not so much sense of beauty and
propriety in art as those races have, even with such degeneracy as
prevails but too widely over the Channel.

It is enough to look at modern London, to listen to the disputes of
committees of management or selection for a public monument, a street,
or a gallery, and to take a glance at their choice, to see what we are
in these respects. But Englishmen are not wanting in genius, and in
the matter of which these pages treat, they have played their part
well in the past.

When buyers know what is ugly, they will not tolerate it about their
houses; the eagerness to possess something new or original will give
place to a just judgment of what is good, whether new or old. Most
periods of good sumptuary art owe their designs to a few old types
constantly reproduced under new and agreeable varieties, that are not
radical changes. To know good from bad in these matters, is the result
not of a natural instinct altogether, but of such a sense instructed
by study, experience, and reflection. Nor, on the other hand, does
such an instinct accompany great intellectual acquirements naturally,
and as a matter of right. A man may possess a vast amount of learning,
statesmanship, or professional knowledge, and be no judge of painting,
sculpture, marquetry furniture, or blue porcelain. Nor, though he
knows something of the history of these objects, will he necessarily
admire and like the best or most beautiful examples. It is this sense
of what is becoming, that has to be learned, though it is occasionally
a natural gift. When whole nations have become used to good domestic
art, public opinion will be sound, and will perpetuate itself as
regards this subject matter, till some great national convulsion
reduces sumptuous living, and refined social manners and habits, to
ruin.


LONDON: PRINTED BY EDWARD STANFORD, 55, CHARING CROSS, S.W.