Silica, alumina, lime.. . Earthenwarecerueibles.
Silica, alumina, oxide of iron, bricks, tiles, encaustic Silica, alumina, lime, oxide oftiles, and common pottery.
Silica, alumina, potash, . Hard porcelain.
Silica, alumina, soda, . . Soft porcelain.
Silica, alumina, magnesia. . Piedmont porcelain. Silica, alumina, baryta, . Stoneware.
It was at one time supposed that the kaolin porcelain clay of China was peculiar to that country, but clays of highest value for all forms of ceramic work are to be found in India, and the white goblets of Arcot and the -light-coloured pottery of Madras show that clays perfectly free from iron can be obtained.
By far the best clay Sir William O'Shauglinessy met with was procured by Captain Halsted at Singapore. It occurs there close to the beach, and can be brought to Calcutta for six annas the maund. The clay is found in thick strata. The detached masses are of a pink tint ; broken into, they contain nodules of perfectly white earth. They absorb water eagerly, and yield an exceed ingly ductile, and tenacious paste. Uparoini or upper wash may be described as a strong brown tenacious or clayey loam. The best is found at a yillage called Monad, ten cos west of Chinsurah, and at Pauchdowkie, eight cos S.W. of Kulna. The raw earth is sold at four annas the maund, but the prepared uparomi is worth three rupees per maund. Three mouths are required for its proper preparation, and ten seers of uparomi are procured from each maund of the raw earth. There are also two other sorts of varnishing earth prepared from this uparomi, whiCh are called gad or sium, obtained at the bottOm of the washing vessel, and majaree or middle sort. All these prepared specimens belutti, uparomi, gad, and majaree—are obtained by wasting, great care being taken to select the water of a very pure tank, no doubt to avoid saline mixtures, which would act as fluxes. The belutti when prepared is a mixture of the yellow Ochre and alumina in slightly variable pro portions.
The ancient potter's wheel is the instrument with which the Hindu works, and while it revolves, With the aid of his naked hands he fashions vessels of elegant forms, many of which have been admired as being of classical shapes, and some would appear almost as if they were of Etruscan origin ; but there is no reason to believe that the Hindus have ever had anything but their own unerring taste to guide them. This beauty of form is equally conspicuous in the pottery of Sewan near Patna, as in that of Azamgarh or of Ahmadabad, of Mirzapore, or of Moradabad. Some of it is remarkable also for its extreme thinness and light ness, showing the great skill of the artist, and making it difficult to understand how it kept its shape when in a plastic state, as it is not known that the turning-lathe is used to give a finish to any of the articles. The painted pottery of Kotah and the gilt pottery of Amroha have also been admired. The handles and the various ornaments of the Ahmadabad pottery are no doubt attached, as in Europe, by means of a slip. It is a horizontal flywheel, the frame of wood, the rim heavily laden with clay, 2 or 3 feet in diameter, weight ,60 to 80 lbs., and is put in motion by the potter's hand, assisted by a stick. Once set spinning, it revolves for from five to seven minutes with a perfectly steady and nearly true motion. The mass of clay to be moulded is placed on the centre of the wheel, and the potter squats before it on the ground.. This machine has doubtless several defects, but it answers Its purpose per fectly. The native furnace is simply an in the ground of variable depth, in which the ware is placed layer by layer, with dry reeds, straw, etc., and all are burnt together.—Juries' Reports, of Exhibitions in India and Europe since 1851 ; Royle, Arts of India O'Sha?ghnessy, Bengal Dispens.; Imp. Gaz. See Ceramic Manu factures; Earthenware ; Porcelain.