a fine kind of earthen ware, chiefly manufactured in China, and thence called China-ware. All earthen wares which are white and semi-transparent are generally called porcelains: but amongst these, so great differences may be observed, that notwithstanding the similarity of their external appearance, they cannot be considered as matters of the same kind. These differences are so evident, that even persons who are not connoisseurs in this way prefer much the porcelain of some countries to that of others.
The word porcelain is of European derivation; none of the syllables which compose it can even be pronounced or written by the Chinese, whose language comprehends
(a) We have seen it above 30 feet high. Porcelain.
It is probable that we are indebted to the Portuguese for it; the word *porcellano*, however, in their language, signifies properly a cup or dish; and they themselves distinguish all works of porcelain by the general name of *loca*. Porcelain is called in China *tsu-ki*.
The art of making porcelain is one of those in which Europe has been excelled by oriental nations. The first porcelain that was seen in Europe was brought from Japan and China. The whiteness, transparency, fineness, neatness, elegance, and even the magnificence of this pottery, which soon became the ornament of sumptuous tables, did not fail to excite the admiration and industry of Europeans; and their attempts have succeeded so well, that in different parts of Europe earthen wares have been made so like the oriental, that they have acquired the name of porcelain. The first European porcelains were made in Saxony and in France; and afterwards in England, Germany, and Italy; but as all these were different from the Japanese, so each of them had its peculiar character.
The finest and best porcelain of China is made in a village called *King-te-ching*, in the province of Kiang-hi. This celebrated village is a league and a half in length, and we are assured that it contains a million of inhabitants. The workmen of *King-te-ching*, invited by the attracting allurements of the European trade, have established manufactories also in the provinces of Fukien and Canton; but this porcelain is not esteemed.—The emperor Kang-hi was desirous of having some made under his own inspection at Pe-k'ing. For this purpose he collected workmen, together with tools, and all materials necessary; furnaces were also erected; but the attempt miscarried. The village of *King-te-ching* still continues the most celebrated place in the empire for beautiful porcelain, which is transported to all parts of the world, and even to Japan.
We are unable to discover who first found out the art of making porcelain, nor is it known whether the Chinese were indebted to chance for it, or to the repeated efforts of inventive genius; we cannot even determine its antiquity with precision; we know only from the annals of Feou-leang, a city in the district to which *King-te-ching* belongs, that, since the year 442 of our era, the workmen of this village have always furnished the emperors with porcelain; and that one or two mandarins were sent from court to inspect their labours. It is, however, supposed that the invention of porcelain is much older than that epocha.
We are indebted to Father d'Entrecolles, a Roman missionary, for a very accurate account of the manner in which porcelain is made in China; and as he lived in *King-te-ching*, his information must have been the very best possible. We shall therefore give his account of the Chinese manner of making it, as abridged by Grosier in his *General Description of China*. The principal ingredients of the fine porcelain are *pe-tun-tse* and *kao-lin*, two kinds of earth from the mixture of which the paste is produced. The *kao-lin* is intermixed with small shining particles; the other is purely white, and very fine to the touch. These first materials are carried to the manufactories in the shape of bricks. The *pe-tun-tse*, which is so fine, is nothing else but fragments of rock taken from certain quarries, and reduced to powder. Every kind of stone is not fit for this purpose. The colour of that which is good, say the Chinese, ought to incline porcelain a little towards green. A large iron club is used for breaking these pieces of rock; they are afterwards put into mortars; and, by means of levers headed with stone bound round with iron, they are reduced to a very fine powder. These levers are put in action either by the labour of men, or by water, in the same manner as the hammers of our paper-mills. The dust afterwards collected is thrown into a large vessel full of water, which is strongly stirred with an iron shovel. When it has been left to settle for some time, a kind of cream rises on the top, about four inches in thickness, which is skimmed off, and poured into another vessel filled with water; the water in the first vessel is filtered several times; and the cream which arises is still collected, until nothing remains but the coarse dregs, which, by their own weight, precipitate to the bottom; these dregs are carefully collected, and pounded anew.
With regard to what is taken from the first vessel, it is suffered to remain in the second until it is formed into a kind of crust at the bottom. When the water above it seems quite clear, it is poured off by gently inclining the vessel, that the sediment may not be disturbed; and the paste is thrown into large moulds proper for drying it. Before it is entirely hard, it is divided into small square cakes, which are sold by the hundred. The colour of this paste, and its form, have occasioned it to receive the name of *pe-tun-tse*.
The *kao-lin*, which is used in the composition of porcelain, requires less labour than the *pe-tun-tse*. Nature has a greater share in the preparation of it. There are large mines of it in the bottoms of certain mountains, the exterior strata of which consist of a kind of red earth. These mines are very deep, and the *kao-lin* is found in small lumps, that are formed into bricks after having gone through the same process as the *pe-tun-tse*. Father d'Entrecolles thinks, that the earth called *terre de Malte*, or St Paul's earth, has much affinity to the *kao-lin*, although those small shining particles are not observed in it which are interperforated in the latter.
It is from the *kao-lin* that fine porcelain derives all its strength; if we may be allowed the expression, it stands it instead of nerves. It is very extraordinary, that a soft earth should give strength and consistency to the *pe-tun-tse*, which is procured from the hardest rocks. A rich Chinese merchant told F. d'Entrecolles, that the English and Dutch had purchased some of the *pe-tun-tse*, which they transported to Europe with a design of making porcelain; but having carried with them none of the *kao-lin*, their attempt proved abortive, as they have since acknowledged. "They wanted (said this Chinese, laughing) to form a body, the flesh of which should support itself without bones."
The Chinese have discovered, within these few years, a new substance proper to be employed in the composition of porcelain. It is a stone, or rather species of chalk, called *hoa-che*, from which the physicians prepare *Chinese*, a kind of draught that is said to be detergent, aperient, and cooling. The manufacturers of porcelain have thought proper to employ this stone instead of *kao-lin*. It is called *hoa*, because it is glutinous, and has a great resemblance to soap. Porcelain made with *hoa-che* is very rare, and much dearer than any other. It has an exceeding fine grain, and, with regard to the painting, if it be compared with that of the common porcelain, it Porcelain:
it appears to surpass it as much as vellum does paper.
This porcelain is, besides, so light, that it surprises those who are accustomed to handle other kinds; it is also much more brittle; and it is very difficult to hit upon the proper degree of tempering it.
Hoa-chee is seldom used in forming the body of the work; the artist is contented sometimes with making it into a very fine size, in which the vessel is plunged when dry, in order that it may receive a coat before it is painted and varnished: by these means it acquires a superior degree of beauty.
When hoa-chee is taken from the mine, it is washed in rain or river water, to separate it from a kind of yellow earth which adheres to it. It is then pounded, put into a tub filled with water to dissolve it, and afterwards formed into cakes like kao-lin. We are assured that hoa-chee, when prepared in this manner, without the mixture of any other earth, is alone sufficient to make porcelain. It serves instead of kao-lin; but it is much dearer. Kao-lin costs only ten-pence Sterling; the price of hoa-chee is half-a-crown: this difference, therefore, greatly enhances the value of porcelain made with the latter.
To pe-tun-tse and kao-lin, the two principal elements, must be added the oil or varnish from which it derives its splendor and whiteness. This oil is of a whitish color, and is extracted from the same kind of stone which produces the pe-tun-tse, but the white is always chosen, and that which has the greencut spots. The oil is obtained from it by the same process used in making the pe-tun-tse: the stone is first washed and pulverized; it is then thrown into water, and after it has been purified it throws up a kind of cream. To 100 pounds of this cream is added one pound of che-kao, a mineral something like alum, which is put into the fire till it becomes red-hot and then pounded. This mineral is a kind of rummet, and gives a confluence to the oil, which is however carefully preserved in its state of fluidity. The oil thus prepared is never employed alone, another oil must be mixed with it, which is extracted from lime and fern ashes, to 100 pounds of which is also added a pound of che-kao. When these two oils are mixed, they must be equally thick; and in order to ascertain this, the workmen dip into each of them some cakes of the pe-tun-tse, and by inspecting their surfaces closely after they are drawn out, thence judge of the thickness of the liquors. With regard to the quantity necessary to be employed, it is usual to mix 10 measures of lime-oil with one measure of the oil made from lime and fern ashes.
The first labour consists in again purifying the pe-tun-tse and the kao-lin. The workmen then proceed to mix these two substances together. For fine porcelain they put an equal quantity of the kao-lin and the pe-tun-tse; for the middling sort they use four parts of the kao-lin and six of the pe-tun-tse. The least quantity put of the former is one part to three of the pe-tun-tse. When this mixture is finished, the mass is thrown into a large pit, well paved and cemented in every part; it is then trodden upon, and kneaded until it becomes hard. This labour is so much the more fatiguing, as it must be continued without intermission; were it interrupted, all the other labourers would remain unemployed. From this mass, thus prepared, the workmen detach different pieces, which they spread out upon large slates, where they knead and roll them in every direction, carefully observing to leave no vacuum in them, and to keep them free from the mixture of any extraneous body. A hair or a grain of sand would spoil the whole work. When this paste has not been properly prepared, the porcelain cracks, and melts or becomes warped.
All plain works are fashioned with the wheel. When and of fa., a cup has undergone this operation, the outside of its 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. He is under the necessity of using expedition, as he is paid not quite a farthing per board, and each board contains 26 pieces. This cup passes then to a second workman, who forms its base. A little after it is delivered to a third, who applies it to his mould, and gives it a proper form; when he takes it off the mould, he must turn it very softly, and be careful not to press it more on one side than on another; without this precaution it would become warped or disfigured. A fourth workman polishes it with a chisel, especially around the edges, and diminishes its thickness, in order to give it a certain degree of transparency. At length, after having passed through all the hands necessary for giving it all its ornaments, it is received, when dry, by the last workman, who fashions its bottom with a chisel. It is astonishing to see with what dexterity and expedition the workmen convey these vases from one to another. We are assured, that a piece of porcelain, before it is finished, must pass through the hands of 70 persons.
Large works are executed in parts which are fashioned separately. When all the pieces are finished, and all works executed and cemented with paste and made of the same substance, and softened with water. Some time after, the seams are polished with a knife, both without and within; and when the vessel is covered with varnish, it entirely conceals them, so that the least trace of them is not to be seen. It is in this manner that spouts, handles, rings, and other parts of the same nature, are added. This is the case, particularly in those pieces which are fashioned upon moulds or modelled with the hands, such as embossed works, grotesque images, idols, figures of trees or animals, and busts, which the Europeans order. All these are formed of four or five pieces joined together, which are afterwards brought to perfection with instruments proper for carving, polishing, and finishing, the different traces which the mould has left imperfect. With regard to those flowers and ornaments which are not in relief, they are either engraved or imprinted with a stamp. Ornaments in relief, prepared separately, are also added to pieces of porcelain, almost in the same manner as lace is put upon a coat.
After a piece of porcelain has been properly fashioned, it then passes into the hands of the painters. These men, or painters in porcelain, are equally diligent as the other workmen; they follow no certain plan in their art, nor are they acquainted with any of the rules of drawing; all their knowledge is the effect of practice, assisted by a whimsical imagination. Some of them, however, show no inconsiderable share of taste in painting flowers, animals, and landscapes, on porcelain, as well as upon the paper of fans, and the silk used for filling up the squares of lanterns. The labour of painting, in the manufactories of which we have spoken, is divided among a great number of hands. The business of one is entirely confined to tracing out the first coloured circle, which ornaments the brims of the vessel; another designs the flowers, and a third paints them; one delineates waters and mountains, and another birds and other animals: human figures are generally the worst executed.
The t'ou-you, which is a kind of oil procured from white flint, has the peculiar property of making those pieces of porcelain upon which it is laid appear to be covered with an infinitude of veins in every direction; at a distance one would take them for cracked vases, the fragments of which have not been displaced. The colour communicated by this oil is a white, somewhat inclining to that of ashes. If it be laid upon porcelain, entirely of an azure blue, it will appear in the same manner to be variegated with beautiful veins. This kind of porcelain is called f'ou-i-ki.
The Chinese make vases also ornamented with a kind of fret-work, perforated in such a manner as to resemble very fine lace. In the middle is placed a cup proper for holding any liquid; and this cup makes only one body with the former, which appears like lace wrapped round it. The Chinese workmen had formerly the secret of making a still more singular kind of porcelain: they painted upon the sides of the vessel fishes, insects, and other animals, which could not be perceived until it was filled with water. This secret is in a great measure lost: the following part of the process is, however, preserved. The porcelain, which the workman intends to paint in this manner, must be extremely thin and delicate. When it is dry, the colour is laid on pretty thick, not on the outside, as is generally done, but on the inside. The figures painted upon it, for the most part, are fishes, as being more analogous to the water with which the vessel is filled. When the colour is thoroughly dry, it is coated over with a kind of size made from porcelain-earth; so that the azure is entirely inclosed between two laminae of earth. When the size becomes dry, the workman pours some oil into the vessel, and afterwards puts it upon a mould and applies it to the lath. As this piece of porcelain has received its confluence and body within, it is made as thin on the outside as possible, without penetrating to the colour; its exterior surface is then dipped in oil, and when dry it is baked in a common furnace. The art of making these vases requires the most delicate care, and a dexterity which the Chinese perhaps do not at present possess. They have, however, from time to time made several attempts to revive the secret of this magic painting, but their success has been very imperfect. This kind of porcelain is known by the name of kia-tsing, "pressed azure."
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 situated sometimes at the other end of King-te-telling. In a kind of portico, which is erected before it, may be seen heaps of boxes and cases made of earth, for the purpose of inclosing the porcelain. Each piece, however considerable it may be, has its case; and the Chinese workman, by this procedure, imitates nature, which, in order to bring the fruits of the earth to proper 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.
In the bottom of these boxes is put a layer of fine sand, which is covered over with powder of the kao-lin, 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, 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 with piles of cases, which defend the pieces they contain from the too direct action of the fire.
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 sprinkled over with the dust of the kao-lin. When the 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, half a foot in thickness; those which occupy the middle space 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 placed at the top of each pile is also suffered to be empty. The piles which contain the finest porcelain are placed in the middle part of the furnace; the coarsest are put at its farther extremity; and those pieces which have the most body and the strongest colouring are near its mouth.
These different piles are placed very closely in the furnace; they support each other mutually 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 infuse itself everywhere around them.
Before each of these furnaces for baking porcelain there is a long porch, which conveys air, and supplies in certain respects the place of a bellows. It serves for the same purposes as the arch of a glasshouse. "These furnaces (says Father d'Entrecolles), which were formerly only six feet in height and the same in length, are constructed now upon a much larger plan: at present they are two fathoms in height, and almost four in breadth; and the sides and roof are so thick, that one may lay the hand upon them without being incommoded by the heat. The dome or roof is shaped like a funnel, and has a large aperture at the top, through which clouds of flame and smoke incessantly issue. Besides this principal aperture, there are five others smaller, which are covered with broken pots, but in such a manner that the workman can increase or diminish the heat according as it may be found most convenient: through these also he is enabled to discover when the porcelain is sufficiently baked. Having uncovered that hole which is nearest the principal aperture, he takes a pair of pincers, and opens one of the cases: if he observes a bright fire in the furnace, if all the cases be red... red-hot, and if the colours of the porcelain appear with full lustre, he judges that it is in a proper state; he then discontinues the fire, and entirely closes 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 this 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 night; after which two men keep continually throwing wood into it, and relieve each other by turns: 180 loads are generally 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."
The Chinese divide their porcelain into several classes, according to its different degrees of fineness and beauty. The whole of the first is reserved for the emperor. None of these works ever come into the hands of the public, unless they have blemishes or imperfections which render them unworthy of being presented to the sovereign. It is much to be doubted whether any of the largest and finest porcelain of China has ever been brought to Europe; the manufacturers at least assure us that none of that kind is sold at Canton. The Chinese set some value upon the Dresden porcelain, and still more upon that which comes from the manufactories of France.
The illustrious Reaumur first attended to the manufacture of porcelain as a science, and communicated his researches in two memoirs before the Academy of Sciences in 1727 and 1729. He did not satisfy himself with considering the external appearance, the painting and gilding, which are only ornaments not essential to the porcelain, but he endeavoured to examine it internally; and having broken pieces of the Japanese, Saxony, and French porcelains, he examined the difference of their grains (which name is given to their internal structure). The grain of the Japanese porcelain appeared to him to be fine, close, compact, moderately smooth, and somewhat shining. The grain of the Saxony porcelain was found to be still more compact, not granulous, smooth, shining like enamel. Lastly, the porcelain of St Cloud had a grain much less close and fine than that of Japan; not, or but little, shining; and resembling the grain of sugar.
From these first observations Mr Reaumur perceived that porcelains differed considerably. That he might examine them further, he exposed them to a violent heat. More essential differences than those of the grain appeared upon this trial; for the Japanese porcelain was unalterable by the fire, and all the European were melted.
This essential difference betwixt the Japanese and European porcelains suggested to Mr Reaumur a very ingenious thought, and in many respects true, concerning the nature of porcelain in general. As all porcelains somewhat resemble glass in consistence and transparency, though they are less compact and much less transparent, Mr Reaumur considered them as semivitrifications. But every substance may appear, and may actually be, in a semivitrified state in two ways: for, first, it may be entirely composed of vitrifiable or fusible Porcelain matters; and in this case, by exposing it to the action of fire, it will be actually melted or vitrified, if the heat be sufficiently strong and long continued. But as this change is not made instantly, especially when the heat is not very violent; and as it passes through different stages or degrees, which may be more easily observed as the heat is better managed: hence, by stopping in proper time the application of heat to porcelain made in this manner, we may obtain it in an intermediate state betwixt those of crude earths and of completely vitrified substances, and also possessed of the semitransparency and of the other sensible qualities of porcelain. We know also, that if such porcelain be exposed to a stronger degree of heat, it will then be completely fused and entirely vitrified. But the European porcelains tried by Mr Reaumur had this fusibility; from which he concluded, that their composition is founded upon the above-mentioned principle.
In the second place, a paste of porcelain may be composed of fusible and vitrifiable matter, mixed with a certain proportion of another matter which is absolutely unfusible in the fires of our furnaces. We may easily perceive, that if such a mixture be exposed to a heat sufficient to melt entirely the vitrifiable ingredient, that this matter will actually melt: but as it is intermixed with another matter which does not melt, and which consequently preserves its consistence and opacity, the whole must form a compound partly opaque and partly transparent, or rather a semitransparent mass; that is, a semivitrified substance or porcelain, but of a kind very different from the former; for as the fusible part of this latter has produced all its effect, and as it has been as much fused as it can be during the baking of the porcelain, the compound may be exposed a second time to a more violent fire, without approaching nearer to a complete vitrification, or without departing from its state of porcelain. But as oriental porcelain has precisely these appearances and properties, Mr Reaumur concludes with reason, that it is composed upon this principle; and he afterwards confirmed his opinion by undeniable facts.
Mr Reaumur examined the pe-tun-tse and kao-lin of the Chinese, and having exposed them separately to a violent fire, he discovered that the pe-tun-tse had fused without addition, and that the kao-lin had given no sign of fusibility. He afterwards mixed these matters, and formed cakes of them, which by baking were converted into porcelain similar to that of China. Mr Reaumur easily found, that the pe-tun-tse of the Chinese was a hard stone of the kind called vitrifiable, but much more fusible than any of those which were known in Europe; and that the kao-lin was a talky matter, reduced to a very fine powder. From that time he hoped to make a porcelain of the same kind as the Chinese with materials found in France. Whether he could not find any materials equal to those of China, particularly that material analogous to the pe-tun-tse of the Chinese, or because other occupations prevented the continuance of his researches, we do not know; but we find, from his second memoir upon porcelain, that he afterwards attempted to make an artificial pe-tun-tse, by mixing our vitrifiable stones with salts capable of rendering them fusible, or even by substituting for it glass ready formed, and by adding to these such sub- stances as he thought might be substituted for kao-lin. But he probably found he could not execute these intentions; for he did not resume this subject from the year 1729 to 1739, when he gave a process for converting common glaas into a singular kind of porcelain, which he had given his name, and of which an account is given under Chemistry, n° 591—594. See also the article Glass-Porcelain.
Although Mr Reaumur has surmounted many difficulties, and has given just notions concerning this subject, yet he has been mistaken, or rather misled, in two important points. His first error concerns the Saxon porcelain, which he confounds with the other fusible porcelains made in Europe. Formerly, indeed, a porcelain might be made in Saxony, composed entirely of fusible or vitrifiable materials, the vitrification of which was flopped in proper time, and which Mr Reaumur had examined. But now we are certainly informed, that all of that country is capable of resisting the most violent fires without fusion, as well at least as those of China and Japan. Mr Reaumur might have been misled by the appearance of the internal texture of this porcelain. For when a piece of it is broken, its internal surface does not appear granulous, but compact, uniform, smooth, shining, and much resembling white enamel. But this appearance, so far from showing that Saxon porcelain is a fused or vitrified substance, proves that it is not entirely composed of fusible matters. All who have considered attentively this subject know, that the internal surface of the most fusible porcelains is also the least dense and least compact; the reason of which is, that no vitreous matter can be smooth and dense internally, unless it has been completely fused. But if the density and shining appearance of the internal surface of the Saxon porcelain were only the effects of the fusion of a vitreous matter, how could we conceive that vessels formed of that matter should have sustained the necessary fusion for giving this density and shining appearance, without having entirely lost their shape? The impossibility of this is evident to any persons who have been conversant in these matters and in the fusion of glaas.
This quality of the Saxon porcelain must therefore proceed from another cause. It does indeed contain, as every porcelain does, particularly those of China and Japan, a fusible substance, which has been even completely fused during the baking. Its density also, and its internal lustre, proceed chiefly from this fused matter: but we are also certain, that it contains a large quantity of a substance absolutely unfusible, from which it receives its admirable whiteness, its firmness and solidity, during the baking; in a word, which supplies the place of the oriental kao-lin, and which has the property of contracting its dimensions considerably while it incorporates with the fusible substance. If it be subjected to the most decisive trial, namely, the action of a violent fire, capable of melting every porcelain composed of fusible matters alone, "I affirm (says Mr Macquer), after many experiments, that it cannot be fused, unless by a fire capable also of melting the best Japanese porcelain." The Saxon porcelain is therefore not to be confounded with those which are vitreous and fusible; but is in its kind as excellent as that of Japan, and perhaps superior, as we shall see when we enumerate the qualities which constitute the excellence of porcelain.
The subject of Mr Reaumur's second error, or at least that which he has not sufficiently explained, is the kao-lin of China. According to him, this matter is a fine talky powder, from the mixture of which with pe-tun-tse the oriental porcelain is formed. Possibly a very finely ground talky substance mixed with pe-tun-tse might form a porcelain similar to the oriental; but persons acquainted with the manufacture of any porcelain must perceive the impossibility of forming vessels, unless the paste of which they are made be so ductile and tenacious that it may be worked upon a potter's lathe, or at least that it may be moulded. But talks, or any kinds of stones, however finely ground, cannot acquire the requisite tenacity, which clays only, of all known earthly substances, possess. The Chinese porcelain vessels evidently appear to be turned upon the lathe, since they retain the marks of it: hence they must have been formed of a very tenacious paste, and consequently the kao-lin is not a purely talky matter, but is mixed with clay; or else the pe-tun-tse and kao-lin are not, as Mr Reaumur supposes, the only ingredients of which Chinese porcelain is formed, but a sufficient quantity of some binding matter, unknown to Father d'Entrecolles and Mr Reaumur, must be also added.
Although, since Mr Reaumur, no scientific person has written concerning porcelain, many have attempted to make it. Manufactories have been established in almost all the states of Europe. Besides that of Saxony, which has been long established, porcelain is also made at Vienna, at Frankenthal, and lately in the neighbourhood of Berlin. All these German porcelains are similar to the Saxon; and are made of materials of the same kind, although they differ somewhat from each other. England and Italy also have their porcelains, the chief of which are those of Chelsea and of Naples. M. de la Condamine, in his last journey into Italy, visited a manufacture of porcelain established at Florence by the marquis de la Ginori, then governor of Leghorn. M. de la Condamine observed particularly the large size of some pieces of this porcelain. He says he saw statues and groups half as large as nature, modelled from some of the finest antiques. The furnaces in which the porcelain was baked were constructed with much art, and lined with bricks made of the porcelain materials. The paste of this porcelain is very beautiful; and from the grain of broken pieces, it appears to have all the qualities of the best Chinese porcelain. A whiter glazing would be desirable, which they might probably attain, if the Marquis Ginori was not determined to use those materials only which were found in that country.
But in no state of Europe have such attempts been made to discover porcelain, or so many manufactories of it been established, as in France. Before even Mr Reaumur had published on this subject, porcelain was made at St Cloud, and in the suburb of St Antoine at Paris, which was of the vitreous and fusible kind, but considerably beautiful. Since that time, considerable manufactories of it have been established at Chantilly, at Villeroy, and at Orleans; the porcelains of which have a distinguished merit. But the porcelain produced in the king's manufacture at Sevres holds at present the first rank from its shining white, its beautiful glazing, and coloured grounds, in which no porcelain Porcelain has ever equalled it. The magnificence of the gilding, the regularity and elegance of its forms, surpass every thing of the kind.
Mr Guettard has published an account of his discoveries on this subject, in the Memoirs of the Academy of Sciences for the year 1765. The kaolin which he employed was a white argillaceous earth, filled with mica, which he found in the neighbourhood of Alençon; and his petunite is a hard, quartzose, grit stone, found abundantly in the same country, with which the streets of Alençon are paved. We also know that Mr Guettard had begun to make his experiments on porcelain with these materials in the year 1751, together with the then Duke of Orleans, to whom he was attached. The Count de Lauraguais, of the Academy of Sciences, engaged in the pursuit of porcelain for several years with uncommon ardour and constancy. He spared no trouble nor expense to attain his purpose, which was to make porcelain equal in all respects to that of China and Japan. He showed some pieces made by him in the year 1766 to the members of the Academy of Sciences. The persons appointed by them to examine it gave their opinion, "that of all the porcelains made in the country, that of the Count de Lauraguais most resembles the porcelain of China and Japan in solidity, grain, and unfusibility." It were to be wished that it possessed equally the other qualities essential to the excellence of porcelain, namely, the whiteness and lustre observable in the ancient Japanese porcelain.
We shall now show what those qualities are which constitute the perfection of porcelain. We must first carefully distinguish the qualities which only contribute to the beauty and external appearance, from the intrinsic and essential properties in which the good and solid quality of porcelain consist. All persons who have made experiments in this way have soon discovered the possibility of making compounds very white, beautifully semi-transparent, and covered with a shining glazing; but which cannot be worked for want of tenacity, are not sufficiently compact, are essentially fusible, are subject to break by sudden application of heat and cold; and, lastly, the glazing of which cracks, becomes rough, and consequently loses its lustre by use, because it is too soft.
On the other side, we shall also find it not difficult to compose very tenacious pastes which shall be capable of being easily worked and well baked; which in the baking shall acquire the desirable hardness and density; which are unfusible, and capable of sustaining very well the sudden change of heat and cold; and, in a word, which shall have all the qualities of the most excellent porcelain excepting whiteness and beauty. We shall soon see that the materials fit for the composition of such porcelains may be found abundantly in every country. The only difficulty, then, in this inquiry concerning porcelain, is to unite beauty and good qualities in one composition; and indeed nature seems to be very sparing of materials fit for this purpose, and therefore perfect porcelain will always be a dear and valuable commodity.
Those potteries which we call stone-ware are not of modern invention, and have all the essential qualities of the best Japanese. For if we except whiteness, on which alone the semi-transparency depends, and compare all the properties of Japanese porcelain with those of our stone-ware, no difference can be found betwixt them. Porcelain. The same grain appears internally in both; the same found is produced by striking them when properly suspended; the same density, the same hardness by which they strike fire with steel, the same faculty of sustaining the heat of boiling liquors without breaking, and the same unfusibility in fire, are observable. Lastly, if the earths of which stone-ware is made were free from heterogeneous colouring matters, which prevent their whites and semi-transparency; if vessels were carefully formed; if all the proper attentions were given; and if these vessels were covered over with a fine glazing—they would be as perfect porcelain as that of Japan. The most perfect porcelain, therefore, is nothing else than a fine white stone-ware.
Earths of this kind are probably more rare in Europe than in Japan and China. And probably also the want of these earths was the cause that the first makers of porcelain in this country confined themselves to an external imitation, by employing nothing but vitrifiable matters with fusible frits and a small quantity of white earth, from which fusible and vitreous porcelains were composed, which might be called false porcelains. But genuine things are much changed since their first attempts. Besides the discoveries of the Count de Lauraguais and of Mr Guettard, genuine white porcelains have been made at Frankendal.
These porcelains are not inferior in any respect to the oriental; they are even much superior in beauty and whiteness to the modern oriental porcelain, which has much degenerated in these respects; they seem even to excel the oriental in the most valuable quality of porcelain, namely, the property of sustaining the sudden change of heat and cold. We cannot judge of the quality of porcelain by a slight trial; for so many circumstances concur to make a piece of porcelain capable or incapable of sustaining the sudden application of heat and of cold, that if at the same time boiling water be poured into two vessels, one of which is good porcelain and the other bad, the former may possibly break and the latter remain entire. The only true method of discovering good porcelain in this respect is, to examine several pieces of it which are daily used; for instance, a set of coffee-cups. But it has been observed, that in many such pieces of oriental porcelain, which have been long and daily used, cracks in the direction of their height may be always perceived, which are never seen in the good European porcelains.
Every one talks of porcelain, and yet few are connoisseurs of it. None can be considered as such but those of the ancients who have long made it an object of their inquiries. That the ancient Japanese porcelain is the most perfect is a general opinion. This porcelain is indeed very beautiful, and we must also acknowledge that its quality is excellent. It has been our model, and has long been the object of our admiration and emulation; but which we have been never able to equal, and which many persons believe never can be equalled. Some persons even decry the Saxon porcelain for a quality which really gives it a superiority to the Japanese, namely, the greater smoothness, lustre, and less granulous appearance of its internal surface than the oriental. The resemblance of this surface to that of glass has evidently suggested this notion; and it would be well founded if the density... Porcelain density and lustre of this porcelain proceeded only from a fusible and vitreous quality; but as they do not, and as this porcelain is as fixed and as unfusible as the Japanese, its density, so far from being a fault, is a valuable quality: for we must allow, that of porcelains equal in other respects, those are best which are most firm and compact. Hence the interior substance of the Japanese porcelain is esteemed for its greater density, compactness, and lustre, than our vitreous sand or frit porcelain; because these qualities indicate greater cohesion, and more intimate incorporation of its parts. For the same reason also the superior density of the Saxon porcelain ought to give it the preference to the Japanese. Besides, nothing would be easier than to give the Saxon porcelain the granulous texture of the Japanese, by mixing with the paste a certain quantity of sand. But the persons who perfected that manufacture were certainly sensible that such a conformity to the Japanese porcelain would lessen the merit of theirs: for we know, that in general porcelains are better in proportion as they contain a larger proportion of clay or earth, and less of sand, flints, or other matters of that kind.
What we have said concerning porcelain in general, and the principal kinds of it, seems sufficient to give just notions of it, if not to persons who without considering the subject are determined to prefer the most ancient, to those, at least, who have made experiments on this subject, or who, having a sufficient knowledge of chemistry, are capable of studying and examining it thoroughly. We shall finish this article by giving a short description of the method of manufacturing porcelain as practised in Europe.
The basis of the porcelains which we have called fusible, vitreous, or false porcelains, is called by artists a frit; which is nothing else than a mixture of sand or powdered flints, with salts capable of disposing them to fusion, and of giving them a great whiteness by means of a sufficient heat. This frit is to be then mixed with as much, and no more, of a white tenacious earth of an argillaceous or marly nature, than is sufficient to make it capable of being worked upon the wheel. The whole mixture is to be well ground together in a mill, and made into a paste, which is to be formed, either upon the wheel or in moulds, into pieces of such forms as are required.
Each of these pieces, when dry, is to be put into a case made of earthen ware (a); which cases are to be ranged in piles one upon another, in a furnace or kiln, which is to be filled with these to the roof. The furnaces are chambers or cavities of various forms and sizes; and are so disposed, that their fire-place is placed on the outside opposite to one or more openings, which communicate within the furnace. The flame of the fuel is drawn within the furnace, the air of which rarefying, determines a current of air from without inwards, as in all furnaces. At first a very little fire is made, that the furnace may be heated gradually, and is to be increased more and more till the porcelain is baked, that is, till Porcelain, it has acquired its proper hardness and transparency; which is known by taking out of the furnace from time to time, and examining, small pieces of porcelain, placed for that purpose in cases which have lateral openings. When these pieces show that the porcelain is sufficiently baked, the first is no longer to be supplied with fuel, the furnace is to be cooled, and the porcelain taken out, which in this state resembles white marble not having a shining surface, which is afterwards to be given by covering them with a vitreous composition called the glazing.
The porcelain when baked and not glazed is called Porcelain biscuit, which is more or less beautiful according to the nature of the porcelain. The manufacture of Sévres excels all others in this respect, and it is therefore the only one which can produce very fine pieces of sculpture; that is, in which all the fineness of the workmanship is preserved, and which are preferable in smoothness and whiteness to the finest marble of Italy.
As no piece of sculpture of this kind can preserve all the delicacy of its workmanship when covered with a glazing, and as sculptors avoid polishing their marble figures, because the lustre of the polish is disadvantageous; therefore, in the manufactures of Sévres, all figures or little statues, and even some ornamental vases, are left in the state of biscuit. The other pieces of porcelain are to be glazed in the following manner.
A glaze is first to be composed suited to the nature of the porcelain to which it is to be applied; for every glaze is not fit for this purpose. We frequently find that a glaze which makes a fine glazing for one porcelain shall make a very bad glazing for another porcelain; shall crack in many places, shall have no lustre, or shall contain bubbles. The glazing, then, must be appropriated to each porcelain, that is, to the hardness and density of the ware, and to the ingredients of its composition, &c.
These glazings are prepared by previously fusing together all the substances of which they consist, so as to form vitreous masses. These masses are to be ground very finely in a mill. This vitreous powder is to be mixed with a sufficient quantity of water, or other proper liquor, so that the mixture shall have the consistence of cream of milk. The pieces of porcelain are to be covered with a thin stratum of this matter; and when very dry, they are to be again put into the furnace in the same manner as before for the forming of the biscuit, and to be continued there till the glazing be well fused. The necessary degree of fire for fusing the glazing is much less than that for baking the paste.
The pieces of porcelain which are intended to remain white are now finished; but those which are to be painted and gilded must undergo further operations. The colours to be applied are the same as those used for enamel painting. They all consist of metallic calcines bruised and incorporated with a very fusible glaze. Crocus
(a) The cases are called by English potters joggars. They are generally formed of coarser clays, but which must be also capable of sustaining the heat required without fusion. By means of these cases the contained porcelain is preserved from the smoke of the burning fuel. The whiteness of the porcelain depends much on their compactness of texture, by which the smoke is excluded, and on the purity of the clay of which they are made. Porcelain, cut of iron furnishes a red colour; gold * precipitated by tin makes the purple and violet; copper calcined by acids and precipitated by an alkali gives a fine green; zaffre makes the blue; earths slightly ferruginous produce a yellow; and, lastly, brown and black colours are produced by calcined iron, together with a deep blue of zaffre. These colours being ground with gum-water, or with oil of spike, are to be employed for the painting of the porcelain with designs of flowers and other figures. For gilding, a powder or calx of gold is to be applied in the same manner as the coloured enamels. The painted and gilded porcelains are to be then exposed to a fire capable of fusing the glaze, with which the metallic colours are mixed. Thus the colours are made to adhere, and at the same time acquire a gloss equal to that of the glazing. The gold alone has not then a shining appearance, which must be afterwards given to it by burnishing with a blood-stone.
The operations for the unfusible porcelains, and also for such as are of the nature of stone-ware, are somewhat more simple. The sands and stones which enter into their composition are to be ground in a mill; the earths or clays are to be washed; the materials are to be well mixed, and formed into a paste; the pieces are first rudely formed upon a potter's wheel; and when dry, or half dry, they are turned again upon the wheel, and their form is made more perfect; they are then placed in the furnace; not to bake them, but only to apply a sufficient heat to give them such solidity that they may be handled without breaking, and may receive the glazing. As the pieces of porcelain after this slight heat are very dry, they imbibe water readily. This disposition affords the application of the glazing. The vitrifiable or vitrified matter of this glazing, which has been previously ground in a mill, is to be mixed with such a quantity of water, that the liquor shall have the consistence of milk. The pieces of porcelain are hastily dipped in this liquor, the water of which they imbibe, and thus on their surface is left an uniform covering of the glazing materials. This covering, which ought to be very thin, will soon become so dry, that it cannot stick to the fingers when the pieces are handled.
The pieces of this porcelain are then put into the furnace to be perfectly baked. The heat is to be raised to such a height, that all within the furnace shall be white, and the cases shall be undistinguishable from the flame. When, by taking out small pieces, the porcelain is known to be sufficiently baked, the fire is discontinued, and the furnace cooled. If the baking has been well performed, the pieces of porcelain will be found by this single operation to be rendered compact, sonorous, close-grained, moderately glossy, and covered externally with a fine glazing. The painting and gilding of this porcelain are to be executed in a manner similar to that already described.
Porcelain-shell, a species of Cypraea.