Pot′ter-y.
Earthenware glazed and baked. Clay possesses the property of plasticity; that is, when moistened, it yields to pressure in any direction without breaking, and when the pressure is removed retains the form imparted. If dried at a moderate heat and then crumbled by pressure, it may be again kneaded, and resume its plasticity; but if baked at a red heat, it acquires a hardness beyond that acquired by mere drying, and if crumbled after baking, can never again become plastic by incorporation with water. Clay unmixed contracts in drying, exfoliates, and falls to pieces. Sand corrects this, and when introduced within given proportions does not impair the elasticity. Natural clays have almost always more or less lime, magnesia, iron, and salt, which complicate the conditions, as they act as fluxes and confer color upon the ware. Iron alone gives a red color; iron and lime, cream-brown. The presence of magnesia in addition to the others gives a brownish yellow. The presence of carbonates is sometimes indicated by holes in the ware, produced by carbonic acid, which escapes in the form of gas. Another effect of the lime is to combine with the alumina and prevent its contraction. At a more intense heat the ingredients assume a nearly vitreous condition, and the oxide of iron assumes a bluish or greenish color. The salt is also decomposed, and its base assists the lime. The magnesia may combine with sulphuric acid derived from pyrites in the clay or sulphur in the coal, and is seen in efflorescence on the inside of the kiln. The Egyptian modes of working the clay, and turning, baking, and polishing the jars, are shown in the tombs of Beni Hassan and Thebes. The clay was kneaded by the feet; formed into clots of a proper size by hand, and placed on the wheel, which was of very simple construction and turned by hand. The handles, as with us, were separately made and subsequently attached. The required ornament was traced on them while soft; they were then dried or baked by the escaping heat from the ovens. The accompanying cut is from a tomb at Beni Hassan, time of Osirtasen or thereabout, 1706 B. C. The aim of the artist was to depict the successive manipulations. Four of the figures are represented working at separate wheels. One forms the inside and lip of the cup as it revolves with the table, holding his thumb dexterously inside against the modified resisting pressure of the left hand. The next man is forming the outside and cutting the cup off at its base, which is not at the bottom of the lump. This is now done by a wire. The third represents another stage of the process, the cup being removed and held aloft in the hand. The fourth man dabs on a new lump of clay, and this completes the series. Cups in various places indicate the character of the manufacture in progress. In the next place, we see a man forming a circular slab of clay. The next is raking the fire. Then follows a man handing a cup to another, who places it on the grate above the opening in the furnace-top, where it is baked. The next man carries off the baked cups in baskets supported on the yoke, which was universally used for carrying. The date of these paintings entirely upsets the statements of Pliny, who attributes the invention of the potter's wheel to Choraebus the Athenian, or Anacharisis the Scythian. These paintings were made and the tombs closed on the mortal dust of their occupants 200 years before Cecrops. [1778] On the walls of the tombs of ancient Egypt are painted Ptah the Creator and Neph the Divine Spirit sitting at the potter's wheel turning clay to form men. See porcelain.As when, before his wheel
Seated, the potter twirls it with both hands, etc.Homer, Iliad, XIII. 5.
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| Egyptian pottery (from Beni Hassan). |
On the clay tablets which we have found at Nineveh, and which are now to be counted by thousands, there are explanatory treatises on almost every subject under the sun: the art of writing, grammars, and dictionaries, notation, weights, and measures, divisions of time, chronology, astronomy, geography, history, mythology, geology, botany, etc. In fact, we have now at our disposal a perfect cyclopaedia of Assyrian science. Sir Henry Rawlinson, 1853.
The chronicler of the “Deipnosophists” goes on to say:— “And indeed the pottery of Attica is deservedly praised. But Eubulus says: ‘Cnidian pots, Sicilian platters, and Megarian jars.’ ” Perhaps no other art has done so much as the ceramic to preserve to us the appearance and habits of the peoples of the past. What with domestic, decorative, and funereal urns and lachrymatories, there are but few nations, it would seem, but have left traces to help us to some conception of their tastes and their capacities. The Metropolitan Museum of New York has a great collection, made by General Di Cesnola, United States Consul at Cyprus See the following works: Marryat's “History of pottery and porcelain,” London, 1857; Burty's “Chefs-d'oeuvre of the Industrial Arts,” Appleton & Co., 1869; “Life of Josiah Wedgwood,” London, 1865. The earthenware of the Greeks and Romans was unglazed, but they covered their pottery with wax, tallow, bitumen, and perhaps other articles, to render them impervious to water, wine, etc. The Romans used molds for ornamenting clay vessels and for making figures of idols, or of limbs, plants, etc., for votive offerings. The Peruvians use tallow, which is spread on while the ware is hot, and becomes partially carbonized. The Etruscan ware has a similar appearance. In Italy and Spain, ancient and modern, wine-jars are rubbed with wax to render them impervious to liquids. The art of making glazed pottery originated with the Chinese, and passed from thence to India, and from thence successively to Arabia, Spain, Italy, Holland. In the Alhambra of Granada some of the rooms are ornamented with glazed tiles. The tomb of Sultan Mahommed Khoda-Bendeh, at Sultanieh in Persia, was built in the thirteenth century, and has green enameled tiles on the outside and blue within. The painted mosque of Gour, in India, built in 1475, derives its name from the number of glazed tiles with which it is ornamented. The Caravanserai of Mayar, near Ispahan, built by the mother of Shah Abbas, about 1550, has a covering of green glazed tiles on the front of the principal gateway. See tile. The material of which the Peruvian pottery was made was a colored earth and blackish clay, well tempered evidently, but apparently without glaze. Singular designs were embodied in their religious and sepulchral vases, which were destined to receive the chicha on sacrifice days. The long throat formed the handle, and a second opening admitted or demitted the air when emptying or filling. They were made double, treble, or quadruple; were engraved, painted, and ornamented in relief. Of all the Polynesians, the Feejees alone had the art of making pottery. They did not have the wheel, but the women artificers made graceful and beautiful forms. Their tools were a small flat stone to form the inside, and a spatula for the outer surface. With these tools they made articles almost as perfect as lathe-formed ware. Dr. Livingstone admired the skill in making pottery evinced by the tribes encountered in his “Expedition to the Zambesi.” The town of Delft, in Holland, became celebrated for the manufacture of earthenware, which is held to have been equal in quality to its Italian progenitor, but inferior in its ornamentation, apparently vying with China in its peculiar and almost grotesque modes of representing natural objects. See Porce-lain. The potteries of Lambeth, London, were started by men from Holland, about 1640. The potteries of Staffordshire soon took the preeminence. John Wedgwood was born at Burslem, England, in 1730, and after a variety of experiences such as would sadden and kill an average man, started a pottery on his own account, where he improved the productions of his art. In his second manufactory he established the white stone-ware, and in the third the creamcolored ware which gave him so much celebrity. He also originated a terra-cotta which could be made to resemble porphyry, granite, Egyptian pebble, and other stones of the siliceous or crystalline kind; a black porcelainous biscuit called basaltes; a white and cane-colored porcelain biscuit, smooth and waxlike: and another white porcelainous biscuit, which receives color from metallic oxides like glass on enamel, in fusion. This property renders it applicable to the production of cameos, and all subjects required to be shown in bas-relief, as the ground can be made of any color, while the raised figures are those of the purest white. He likewise invented a porcelain biscuit nearly as hard as agate, which will resist the action of almost all corrosive substances, and is consequently well adapted for mortars in the chemist's laboratory. While honoring the names of those who have distinguished themselves in making pottery an art, we must remember Charles Avisseau (born, 1796) the potter of Tours, the city celebrated for the great victory gained by Charles Martel over the Saracens, October 10. 732.--a victory which, under God, determined the language, religion, and the form of civilization of Europe. Palissy had died three centuries before, the secret of his process dying with him, and Avisseau set about rediscovering the lost art. He succeeded in firing the wares without their undergoing any change and without the use of white glaze. He also composed a series of colors, all fusible at the same temperature, and also a gold enamel. He refused offers to devote his talents to the national establishment of Sevres, preferring to maintain his independence and devote himself to a life of experiments and labor at his humble home in Tours. The materials chiefly used in the North Staffordshire potteries are a light brown clay from Poole in Dorsetshire, and white clay from Cornwall, to which pulverized flint or granite is frequently added. The clays are derived from decomposed granite, and are prepared by mixing them in a plunger containing a large wheel, by which they are, with the addition of water, converted into a mass of the consistency of cream. This is run off into small reservoirs. termed arks, whence it is pumped up and passed through a series of sieves, by which it is reduced to slip. This is forced, under a pressure of 80 pounds to the square inch, into chambers, shallow pans over which are placed linen covers, in which the slip is received, permitting the escape of the expelled moisture and leaving it of a doughy consistency. It is then passed through a pug, a chamber having a spiral revolving blade, where it is hardened and compressed, and after being formed into large square cakes is placed in a dark cellar, where it undergoes the process of fermentation. From these blocks are formed stilts and spurs, used for supporting pieces of pottery and porcelain in the drying-stoves. The blocks are placed in a rectangular chamber having a piston by which the clay is forced out through apertures of square, round, triangular, or other form adapted to the machine employed in the succeeding process. The flat pieces are called backs: the others, shapes. These are cut by a guillotine-like instrument into proper lengths, and then stamped by means of [1779] leaden dies in a press, by which a large number are formed at each impression. The stilts or spurs are generally of triangular form, and have sharp projecting points. They are now placed in oval saggars, made of marl, which are inserted in a furnace and exposed to an intense heat for forty hours. Common door-knobs, furniture casters, telegraph insulators, and similar articles are turned in the usual manner, while lock furniture of colored porcelain is stamped in dies from the dry clay-dust; these are then baked and dipped in glaze, which is afterward melted in ovens.Offspring of clay and furnace bright,
The choicest pottery clear and light,
Boasts, as its birthplace, of the towers
Which Neptune's and Minerva's powers
From ills and dangers shield;
Which beat back war's barbaric wave
When Mede and Persian found a grave
On Marathon's undying field.Critias; quoted by Atheneus, A. D. 220.
