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'Porcelain.

Grosier's general descript. of China.

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and history of it.

tion.

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1. History of the Manufacture of Porcelain in China.

THE fullest account which has yet been received in Europe of the manufacture of Chinese porcelain, bas been given by Father D'Entrecolles, a Romish mission ary, who lived for some time in the village or town where the principal manufactory is established. The account which is given of this village, and of the manufacture of porcelain, by this author, is the following:

This village or town, which is celebrated as producing the best porcelain of China, is in the province of Kiangsi, and it is said to be a league and a half in length, containing not less than 1,000,000 of inhabitants. Other manufactories, indeed, have been established in different parts of the Chinese empire, and particularly in those places which are convenient for the European trade, as in the provinces of Fo-kien and Canton; but the porcelain produced at these manufactories is said to be held in inferior estimation. A Chinese emperor wishing to have a manfacture of porcelain under his own inspection at Pekin, ordered workmen to be collected for the purpose, with all the necessary materials and implements; but after erecting furnaces and other expensive operations, the attempt failed, so that King-te-tching, in the time of our author, continued to be the most celebrated place in China for beautiful porcelain, and from this it was transported to all parts of the world.

Materials The chief ingredients which enter into the composition employed in of fine porcelain are petuntse and kaolin, two kinds of its composi-earth from the mixture of which the paste is obtained. The petuntse is of a pure white, and, when fully prepared, is in the form of an impalpable powder, so that it is very fine to the touch. The kaolin, he observes, is intermixed with small shining particles. These materials are carried to the manufactory in the shape of bricks. The petuntse is originally the fragments of rock dug out from certain quarries, and reduced to powder, and the colour of the stone which answers the purpose best, according to the Chinese, inclines somewhat to green. The fragments of rock are broken to pieces with a large iron club; they are then put into mortars, and by means of levers headed with hard stone, strongly secured with Prepara- iron, they are reduced to the state of fine powder. The tion of pe- levers, it is scarcely necessary to observe, are moved ei

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tuntse,

ther by the labour of men, or by water. The powder, which is afterwards collected, is thrown into a large vessel of water, which is strongly agitated with an iron shovel. When this mixture has been allowed to settle for some time, a substance resembling cream rises to the top, which is skimmed off, and poured into another vessel also filled with water. The water in the first vessel is again agitated, and the frothy substance which rises to the surface is collected as before, and the same operation is repeated till it appear that nothing remains but a coarse sediment which falls to the bottom by its own weight. This sediment is carefully collected, and again subjected to the process of pulverization.

The fluid in the second vessel is allowed to remain at rest till a sediment is produced, forming a kind of crust at the bottom; and when the water above seems to be quite transparent, it is poured off by gently inclining the vessel, that the sediment may not be disturbed. The paste is then put into large moulds, and allowed to dry slowly; but before it becomes quite hard, it is divided

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The kaolin, the other substance which is employed and of in the fabrication of porcelain, requires fewer opera- kaolin. tions in its preparation than the former, as it is found in nature in a state almost ready for the manufacturer. Of this substance it is said, that there are extensive mines in certain mountains; the external strata of which are composed of a kind of red earth. The kaolin is found in these mines in small lumps, and it is formed into bricks by being subjected to a similar process with the petuntse, &c.

The fine porcelain, it has been observed, derives its Nature of fabric and texture from the kaolin. It is to this that the the finer porcelain qualities which it possesses of resisting the most powerful agents is owing; and it has been remarked as an extraordinary circumstance, that a soft earth should communicate strength and consistency to the petuntse, which is obtained from some of the hardest rocks. The author relates an anecdote which he received from a

rich Chinese merchant, that the English and Dutch having purchased a quantity of petuntse, conveyed it to Europe for the purpose of manufacturing porcelain ; but having procured none of the kaolin, the attempt failed. They wanted, added the Chinese with a smile, to form a body, the flesh of which would support itself without bones.

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It is said that the Chinese have discovered of late Substitute years a new substance which may be employed in the for kaolin. composition of porcelain. This stone is called hoa-chè, the first part of the word signifies glutinous, because it is of a saponaceous quality. Porcelain made with this substance is very rare, and bears a much higher price than any other. The grain is extremely fine, and the painting with which it is ornamented, when compared with that of common porcelain, seems to exceed it as much as vellum surpasses paper. This variety of porcelain, it is added, is also remarkable for its lightness. It is besides much more brittle, and it is found difficult to hit upon the proper degree of heat for tempering it. This substance, we are farther informed, is but rarely employed in the fabrication of the body of the porcelain; the reason of this perhaps is, the scarcity and high price of this precious article, in consequence of which the workman is contented with making it into a fine size, into which the vessel is immersed when it is dry, that it may receive a coat before it is painted and glazed; and by this process he finds that he can communicate to the ware a high degree of beauty. The previous processes in the preparation of this substance are similar to those which are followed in the preparation of kaolin. When hoa-che is dug out from the mine, it is washed in rain or river water, for the purpose of separating a yellowish earth with which it is contaminated. It is then reduced to powder, thrown into a vessel filled with water, and then formed into cakes. The hoa-chè prepared in this manner, without the addition of any other earth, is said to be alone sufficient in the fabrication of porcelain. It is employed, as bas been already noticed, as a substitute for kaolin; but, on account of its scarcity, is much dearer. The price of the former is three times that of the latter, and from this circumstance the value of porcelain made with hoa

Porcelain. chè is much higher than that which is manufactured with kaolin.

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-laterial or glazing orcelain.

The principal ingredients in the fabrication of porcelain are petuntse and kaolin; but to these must be added the glaze or varnish, or, as it is called in the account given of Chinese porcelain, the oil, on which depend its splendour and whiteness. This varnish is of a whitish colour, and is obtained from the same kind of stone which yields the petuntse; but for this purpose the whitest stone is always preferred. The glaze is obtained by a process similar to that which is followed in the preparation of petuntse. This stone is first washed and reduced to powder; it is then thrown into a vessel with water, and after being purified, a frothy matter rises to the surface. To 100 pounds of this matter, one pound of a substance called che-kao, is added. This latter is a saline substance, somewhat like alum, which is put into the fire, and allowed to remain till it become red hot, when it is reduced to powder. By the addition of this substance the glaze acquires a greater degree of consistence, but at the same time a proper degree of fluidity must be preserved. The glaze prepared in this manner is not employed alone. Another glaze is mixed with it, which is obtained from lime and ashes; to 100 pounds weight of which is also added one pound of che-kao, or the aluminous substance mentioned above. When the two substances are mixed, it is necessary to attend that they be nearly of the same consistence, and the workman ascertains this point by dipping into each of them some cakes of petuntse; and by a close examination of their surfaces after they are drawn out, he is able to judge of the consistence of the fluids. The proportions of the two which are usually employed, are 10 parts of the glaze obtained from the stone, to one of that which is prepared from the lime and from ashes.

In the manufacture of the Chinese porcelain, the first process after the separate preparation of the materials, is a second purification of the petuntse and kaolin; and when they are found to be in a state of sufficient purity, the workmen proceed to mix the two inoportion gredients together. The proportions employed for the finer kinds of porcelain are equal parts of kaolin and re of the petuntse; for an inferior kind, four parts of kaolin to gredients. six of petuntse are employed; and in some kinds of por

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id mix

celain, only one part of the former is added to three of the latter. This is the smallest proportion of kaolin which is employed in the Chinese manufactories. When the proportions are fixed, and the mixture finished, the mass is thrown into a large pit, which is well paved and cemented. It is then trodden upon, and kneaded till it become hard. This is the most fatiguing part of the labour, for it must be continued without intermission. From the mass prepared in this manner the workmen detach different pieces, which they spread out upon large slates, where they knead and roll them in all directions, taking care that no vacuum be left, and that there be no mixture of any foreign body. The whole work would be entirely spoiled by the addition of a hair, or a particle of sand. When the paste has been properly prepared, the porcelain, when exposed to heat in the furnace, retains its form without becoming soft, or entering into fusion, and becomes semitransparent, without exhibiting cracks or superficial fissures; but when there is any defect in the mixture or preparation, the VOL. XVII. Part I. +

porcelain cracks, and becomes warped, or melts in the Porcelain. furnace.

The paste being thus prepared, the next operation is 13 Method of to form the vessels for which it is designed. All kinds forming of plain ware are formed with the wheel. When a cup, porcelain for instance, has undergone this operation, the outside ware. of the bottom is quite round. The workman first gives it the requisite height and diameter, and it comes from his hands almost the moment he has received it. Great dexterity and expedition are absolutely necessary, on account of the low price of labour in these manufactories. A workman, it is said, scarcely receives a farthing per board, each board containing no less than 26 pieces. The cup then passes to a second workman, by whom the base is formed; it is then delivered to a third, who applies it to the mould, and gives it the proper form. When it is taken off the mould, it must be turned carefully, and not pressed more to one side than the other; for without this necessary precaution it would become warped or disfigured. The business of the fourth workman is to polish it with the chisel, especially round the edges, and diminish the thickness, to give it the proper degree of transparency. Having at length passed through the different hands from whom it receives its form and various ornaments, it then comes to the last workman, who forms the bottom with a chisel. It is wonderful, it is said, to see with how much dexterity and expedition the workmen convey the vessels from one to another; and it is added, that a single piece of porcelain, before it is completely finished, must pass through the hands of no fewer than 70 different workmen. It is indeed, we may observe, to this minute division of labour that its low price is owing; and on the same circumstance the remarkable dexterity and expedition which have been noticed, depend.

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Of large

In the execution of large works of porcelain, different parts are first formed individually; and when all the pieces works. are finished, and nearly dry, they are put together and cemented with a paste formed of the same substance, and softened with water. Some time after, the seams are polished with a knife on both sides of the vessel, so that when it is covered with a varnish, or glazed, they are so completely concealed, that the least trace of them is not perceptible. It is in this way that spouts, handles, rings, and other parts of a similar nature, are united. In this way particularly are fabricated those pieces which are formed upon moulds, or by the hand, such as embossed works, grotesque images, idols, figures of trees or animals, and busts. All these are formed of four or five pieces joined together, which are afterwards brought to perfection by means of instruments proper for carving, polishing, and finishing the different traces which the mould has left imperfect. Flowers and ornaments which are not in relief, are either engraved, or the impression is made by means of a stamp; but ornaments in relief are prepared separately, and added to the pieces of porcelain to which they are destined.

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The piece of porcelain being prepared according to Paintings the operations now described, is next conveyed to the painter: and in this art it is observed that the Chinese workmen follow no certain rule, and seem to be unacquainted with any of the principles of perspective. Their knowledge is the effect of practice, guided often by a whimsical imagination. The labour of painting porcelain in the Chinese manufactories is also divided

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Veined por-
A peculiar kind of glaze or varnish, we are informed,
celain and is obtained from white flint. This glaze, it is said, has
fret-work. the singular property of making the pieces of porcelain

to which it is applied exhibit the appearance of veins
distributed in all directions. Vessels glazed with this
material seem as if the surface were cracked, without the
fragments being separated or displaced. The colour of
this glaze is whitish gray; and when it is applied to
porcelain having an azure blue ground, it communi-
cates a beautifully variegated appearance. Vases of Chi-
nese porcelain are sometimes fabricated in a different
manner. They are ornamented with a kind of fret
work, which has something of the appearance of fine
lace, in the middle of which is placed a cup proper for
holding any liquid; which constitutes one body with the
surrounding fret-work.

Porcelain. among a great number of hands. The business of one some measure as a substitute for bellows. This porch Porcelais. man, for instance, is solely limited to tracing out the answers the same purpose as the arch of a glass-house; first coloured circle with which the brim of the vessel is but the furnaces which, as the author from whom the adorned; another designs the flowers, and a third paints account is taken observes, were formerly only six feet in them. One delineates waters and mountains, while it height, and the same in length, are now constructed is the province of another to draw and paint birds and upon a much more extensive plan. They are 12 feet other animals. Of the painting on Chinese porcelain, high, and nearly four broad; and the roof and sides are it has been observed, that the human figure is often most so thick, that the powerful heat which is applied interindifferently executed. nally does not penetrate to the outside, at least so much as to be inconvenient to bear it on the application of the hand. The dome or roof is in the form of an inverted funnel, having a large aperture at the top by which the smoke escapes. Beside the principal aperture, there are five others of smaller dimensions, which are covered with broken pots in such a manner that the workman can increase or diminish the heat as he finds it necessary. Through these apertures also be is able to see the progress of the baking of the porcelain, and can judge when it is completed. By uncovering the hole which is nearest the principal opening, he opens with a pair of pincers one of the cases containing the pieces of porcelain, and if he perceives a bright fire in the furnace, and all the pieces brought to a red heat, as well as the colours of the porcelain appearing with a full lustre, he concludes that the process is finished. He then diminishes the fire, and entirely shuts up the mouth of the furnace for some time. In the bottom of the furnace there is a deep hearth about two feet in breadth, over which a plank is laid, in order that the workman may enter to arrange the porcelain. When the fire is kindled on the hearth, the mouth of the furnace is immediately closed up, and an aperture is left only sufficient for the admission of faggots, about a foot in length, but very narrow. The furnace is first heated for a day and a night, after which two men keep continually throwing wood into it, and relieve each other by turns. One hundred and eighty loads are consumed for one baking. As the porcelain is burning hot, the workman employs for the purpose of taking it out, long scarfs or pieces of cloth, which are suspended from his neck.

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Singular kind of porcelain.

18 Chinese furnaces.

We are informed that the Chinese workmen formerly possessed the secret of fabricating a kind of porcelain of a more singular nature. On the sides of the vessel thus formed were painted the figures of fishes, insects, and other animals, which could not be seen unless the vessel was filled with water. It is said that this secret is in a great measure lost; but the following is given as part of the process of preparing this kind of porcelain. The vessel which is to be painted, for the purpose of producing this peculiar effect, must be extremely thin and delicate. When it is dry, the colour is laid on, not on the outside, however, as is usually the case, but on the inside of the vessel, and it is laid on pretty thick. The figures which are painted upon it are usually fishes, as being more characteristic of the element in which they live. When the colour is perfectly dry, it is coated over with a kind of glaze, composed of porcelain earth, so that the azure is thus inclosed between two layers of earthy matter; and when the glaze becomes dry, the workman pours some oil into the vessel, and putting it upon a mould, applies it to the lathe. Porcelain fabricated in this manner, having received its consistence and body within, it is the object of the workmen to make it as thin as possible on the outside, without penetrating to the colour. The external surface is then dipped into a mixture for glazing, and when it is dry it is baked in a common furnace. This kind of porcelain is known by the name of kia-tsing, signifying pressed azure. supposed that the Chinese do no at present possess the art of making porcelain of this description, which requires a great deal of dexterity and delicate management; and it is added, that they have imperfectly succet ded in the attempts which have been occasionally made to discover the secret of this curious process.

It is

The next process in the manufacture of porcelain is baking; but before we describe the method of arranging and managing the furnaces employed for this purpose, we shall give a short account of their construction. The Chinese furnaces for baking porcelain are furnished with a long porch, for the purpose of conveying air, and in

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baking per

celain.

Having thus given a concise account of the con Method of struction of the Chinese furnaces, we proceed now to lay before our raaders the method of baking porcelain which is followed in that country. After the porcelain has received its proper form, its colours, and all the intended ornaments, it is transported from the manufactory to the furnace, which is sometimes situated at the other end of the village already mentioned. In a kind of portico, which is erected before it, may be seen vast numbers of boxes and cases made of earth, for the purpose of inclosing the porcelain. Each piece, however inconsiderable it may be, has its own case; and the Chinese workman, by means of this procedure, imitates nature, which, in order to bring the fruits of the earth to maturity, clothes them in a covering, to defend them from the excessive heat of the sun during the day, and from the severity of the cold during the night.

A layer of fine sand is put into the bottom of these boxes, which is covered over with the powder of kaolin, to prevent the sand from adhering too closely to the bottom of the vessel. The piece of porcelain is then placed upon this bed of sand, and pressed gently down, in order that the sand may take the form of the bottom of the vessel, which does not touch the sides of its case: the case has no cover. A second, prepared in the same manner,

Torcelain. manner, and containing its vessel, is fitted into the first, so that it entirely shuts it, without touching the porcelain which is below; and thus the furnace is filled up with piles of cases, which defend the pieces they contain from the direct action of the fire.

20 ifferent

With regard to small pieces of porcelain, such as tea-cups, they are inclosed in common cases about four inches in height. Each piece is placed upon a saucer of earth about twice as thick as a crown-piece, and equal in breadth to its bottom. These small cases are also When the sprinkled over with the dust of the kaolin. cases are large, the porcelain is not placed in the middle, because it would be too far removed from the sides, and consequently from the action of the fire.

These piles of cases are put into the furnace, and placed upon a bed of coarse sand six inches thick; those by which the middle space is occupied are at least seven feet high. The two boxes which are at the bottom of each pile remain empty, because the fire acts too feebly upon them, and because they are partly covered by the sand. For the same reason, the case which is placed at the top of each pile is also allowed to remain empty. The piles containing the finest porcelain are placed in the middle part of the furnace; the coarsest are put at its farthest extremity; and those pieces which have the most body and strongest colouring are near its mouth.

These different piles are placed very closely in the furnace; they materially support each other by pieces of earth, which bind them at the top, bottom, and middle, but in such a manner, that a free passage is left for the flame to insinuate itself everywhere around them.

The Chinese divide their porcelain into several kinds 'nds of or classes, distinguishing each according to the different reelain. degrees of beauty and fineness. The whole of the first or most perfect kind is reserved for the emperor; none of it, we are assured, ever comes into the hands of the public, unless, on account of blemishes or imperfections, it is unworthy of being presented to the sovereign. Many have doubted whether at any time the largest and finest porcelain of China has ever been brought to Europe. None of that kind, at least, is offered to sale at Canton. The Chinese, who are apt to undervalue the productions of other countries, entertain a favourable opinion of the Dresden porcelain, and hold in still higher estimation the porcelain which is produced in the French manufactories.

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China

The following is a short account of the Chinese porr George Caunton's celain manufactures by Sir George Staunton. "From count of the river," says he, "were seen several excavations made e manu in extracting from the sides of the adjoining hills, the cture of petuntse useful in the manufacture of porcelain. This Freelain material is a species of fine granite, or compound of quartz, feldspar, and mica, in which the quartz seems to bear the largest proportion. It appears from several experiments, that it is the same as the growan stone of the Cornish miners. The micaceous part, in some of this granite from both countries, often contains some particles of iron, in which case it will not answer the potter's purpose. This material can be calcined and ground much finer by the improved mille of England, than by the very imperfect machinery of the Chinese, and at a cheaper rate than the prepared petuntse of their own country, notwithstanding the cheapness of labour there.

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"The kaolin, or principal matter mixed with the pe- Porcelain. tuntse, is the growan clay also of the Cornish miners. The wha-she of the Chinese is the English soap-rock; and the she-kan is asserted to be gypsum. It was related by a Chinese manufacturer in that article, that the asbestos, or incombustible fossil stone, entered also into the composition of porcelain. A village, or unwalled town, called Kin-te-chin, was not very far distant from this part of the present traveller's route, in which 3000 furnaces for baking porcelain were said to be lighted at a time, and gave to the place at night the appearance of a town on fire. The genius or spirit of that element is indeed, with some propriety, the principal deity worshipped there. The manufacture of porcelain is said to be precarious, from the want of some precise method of ascertaining and regulating the heat within the furnaces, in consequence of which their whole contents are baked sometimes into one solid and useless mass. Mr Wedgwood's thermometer, founded on the quality observed by him, of clay contracting in proportion to the degree of fire to which it is exposed, might certainly be of use to a Chinese potter*.".

2. Inquiries of Reaumur into the Nature of Porcelain.

* Embassy to China, ill. 299:

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Composition of por

The first scientific investigation which was made into the nature of porcelain, was undertaken by the celebrated Reaumur; and the result of his researches was communicated to the French Academy of Sciences in the years 1727 and 1729. It was not the external form or appearance, nor was it the decorations of painting and gilding, which are by no means essential to porcelain, celain exthat constituted the object of his inquiries. His exami- amiued. nation was particularly directed to the peculiar texture and fabric of this substance, with the view of ascertaining the nature and proportions of its constituent parts. For this purpose, he broke to pieces some of the Japanese, the Saxon, and the French porcelains, and carefully noted the peculiarities and differences in their texture. The grain or texture of the Japanese porcelain appeared to possess a considerable degree of closeness and compactness, with a smooth and somewhat shining as pect.

In his

He found that the Saxon porcelain was still more compact, and that it was smooth, and shining like enamel, but had nothing of the granular texture. examination of the French porcelain, he observed that it had much of the shining appearance, and that its grain was not so close and fine as that of the oriental porcelain, having some resemblance to the grain or texture of sugar. Such were the observations which occurred to the French philosopher at the commencement of his inquiries into the nature of porcelains, and hence be justly concluded, that they were characterised by very marked differences.

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Proceeding in his investigation, the same philosopher Effects of subjected different porcelains to the action of heat; and heat on the result of his experiments with this powerful agent porcelain. proved, that they might be distinguished by still more decisive characters; for it appeared that the porcelain of the east suffered no change from the action of the greatest heat, whereas that of European manufacture underwent fusion at no very high temperature. remarkable difference between the Chinese and European porcelains, suggested to Reaumur an ingenious thought, which at last led him to the discovery of the A a 2

This

true

different nature, quite refractory, and totally infusible. Porcelain. After this discovery Reaumur, it would seem, entertained hopes that he might find materials in France, capable of making porcelain, possessing the same valuable qualities as that of China; but whether his researches in the discovery of proper materials in his own country, particularly that which corresponds to the petuntse of the Chinese, or whether he was prevented by other avocations from prosecuting his inquiries, it does not appear. But in his second memoir upon porcelain, we find, that he afterwards attempted to compose an artificial petuntse, by mixing vitrifiable stones with such saline bodies as were capable of rendering them fusible, or even by substituting for this artificial preparation glass ready formed, with the addition of such matters as he supposed might be successfully employed in the place of kaolin; but it would appear that he did not at the time prosecute his inquiries, for the subject was not resumed till the year 1739, when he announced the discovery of a process for converting common glass to a peculiar kind of porcelain, which has been since known by the name of Reaumur's porcelain.

Porcelain, true nature of the composition of porcelain. Having observed that all porcelains have some resemblance to glass in some of their general properties, although they are less compact, he considered them as in the state of a semivitrified substance. An earthy substance, he observed, may be in a semivitrified state in two ways. It may, in the first place, be entirely composed of vitrifiable or fusible matters; and this being the case, when it is exposed to the action of fire, provided the heat be sufficiently strong and long continued, it will be melted or vitrified. But as this change is not effected instantly, particularly where a violent degree of heat is not applied; and as it passes through different degrees, the progress of which may be more easily observed, according as the heat is managed and regulated; it followed, that by stopping in proper time the application of the heat to porcelain prepared in this way, the ware may be obtained in an intermediate state between those of crude earths and completely vitrified substances, while, at the same time, it possesses the semitransparency and other distinguishing properties of porcelain. Porcelain of this nature, it is well known, being exposed to a stronger degree of heat, undergoes perfect fusion and complete vitrification. All the European porcelains which were subjected to experiment by Reaumur, were found to be of this fusible nature.

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Porcelain

infusible matter.

But on the other hand, porcelain may be composed composed of of fusible or vitrifiable matter, mixed in certain proporfusible and tions with another matter, which is absolutely infusible in the strongest heat to which it can be exposed in the furnace; and hence, if a mixture of this kind be subjected to a heat suflicient to melt entirely the vitrifiable part of its composition, this will enter into fusion; but being mixed with another matter which is infusible, and which consequently retains its consistency and opacity, the whole will form a compound, partly opaque, and partly transparent, or, in other words, a semitransparent mass; that is, a semivitrified substance, or porcelain, but possessing qualities totally distinct from those of the former. For as the fusible part of the latter has been brought to its utmost degree of fusibility during the process of baking, although the compound may be exposed a second time to a still stronger degree of heat, it will not approach nearer to complete vitrification, that is, it will retain all the qualities of perfect porcelain. Reaumur found that the porcelain of the east was distinguished by the properties now described; and hence he con cluded, that its component parts were arranged on the principle above alluded to. This opinion was afterwards confirmed by the most incontrovertible facts, deduced from a train of the most satisfactory and well directed experiments.

25 The kaolin infusible,

the pe

tuntse a

matter.

The ingredients which enter into the composition of the Chinese porcelain, namely, the petuntse and kaclin, were the next object of Reaumur's inquiries. Having obtained quantities of each, he subjected them separatevitrifiable ly to a strong heat, and he found that the petuntse entered into fusion, without addition; but it appeared that the kaolin was absolutely infusible. He then mixed the two ingredients, formed them into cakes, and exposed them in a furnace to the proper degree of heat; so that by baking they were converted into porcelain exactly similar to that of the Chinese. From these experiments it appeared, that the petuntse of the Chinese was a vitrifiable substance, and that the kaolin was of a

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Although it must appear, from the detail now given, Mistaker of that Reaumur was directed in his researches by the true Reaum spirit of philosophical inquiry, he seems to have been misled in certain points. One of his errors was relative to the Saxon porcelain, which he confounded with the other fusible porcelains of European manufacture, unless it be supposed that the porcelain of Saxony was formerly composed of entirely fusible or vitrifiable matters, and that it was porcelain of this description which he exmined; for it is now certain, that all the porcelain of that country is capable of resisting the most powerful heat, and is therefore equally infusible with that of China or Japan. The appearance of the internal texture of the Saxon porcelain may have led the philosopher to this erroneous conclusion; for when it is broken, the internal surface does not exhibit a granular texture, but is uniform, smooth, shining, and compact, having much resemblance to white enamel. This appearance, however, so far from proving that the porcelain of Saxony is a fused or vitrified substance, shews, that it is not entirely composed of fusible matters. The internal surface of the most fusible porcelains, it is well known to those who are acquainted with the subject, is also the least dense, and the least compact; for no vitreous matter can be internally smooth and dense, without having been in a state of complete fusion. But if relative to the density and shining appearance of the porcelain of Saxony depended only on the effects of the fusion of a vitreous matter, how is it to be supposed, that vessels formed of that fusible matter should have sustained the necessary degree of heat for producing the density and shining appearance, without having entirely lost their shape?

This peculiar quality of the Saxon porcelain, it is inferred, must then depend on another cause. Like every other porcelain, especially that of China and Japan, it contains a fusible substance, which has been in a state of complete fusion during the process of baking. The density and the internal lustre depend chiefly on this fused matter; but it is also certain, that the Saxon porcelain contains a large proportion of a substance which is absolutely infusible, and from which it derives its beautiful white appearance, its firmness and solidity,

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the Saxon

porcelain,

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