Stone-ware is very seldom glazed by a “dip.” The usual method is to combine the firing and glazing. When the ware has been exposed to the maximum heat for the necessary time, salt is thrown into the kiln. The heat vaporizes the salt, and of its constituent parts one, the chlorine, escapes; while the other, the soda, is, on coming in contact with the silex in the red-hot ware, formed into a silicate of soda, a perfectly transparent and intensely hard glaze. In regard to the colors, the only ones now known which will bear the first firing--_couleurs de grand feu_--and are therefore put on before glazing, are blue from cobalt, browns from iron, manganese, and chromate of iron, green from chrome, and yellows from titanium and uranium. Between these and the more delicate _couleurs de moufle_, or enamel colors, are violets, reds, and browns from manganese, copper, and iron, which are designated as _couleurs au demi grand feu_. Beyond these, the colors used in decorating hard or natural porcelain are laid on the glaze, to which they adhere without incorporating themselves. The great difficulties attending the manufacture of porcelain may now be estimated. The piece must pass through the kiln as many times as there are colors requiring different temperatures. Too much heat will blot out the delicate colors, too little will leave them dull. Those on artificial or soft porcelain sink into the glaze, and thus present a softness and creamy delicacy never seen on any other kind of ware. The results are generally a sufficient reward for the difficulty of the process. This is altogether exceptional in the case of _pate tendre_. As its alkaline ingredients volatilize at a certain heat, the fire must be stopped before that temperature is reached. The glaze, also alkaline, is then applied in the form of dust, and not, as with hard porcelain, in the form of a dip. The second firing melts the glaze. If the heat be too strong, the alkalies will fly off; if too weak, the surface will be uneven. For a third time the same danger is incurred, when the firing for fixing the colors takes place. BOOK II.--THE ORIENT. CHAPTER I. EGYPT. The East the Cradle of Art.--The Antiquity of Egypt: Its Claim to Notice in every Branch of Inquiry.--The Fountains of Oriental and Greek Art.--The Nile Clay.--Egypt’s Early Maturity.--Limitation of Material.--Effect of Religion upon Art.--Two Periods in Art History.--Ancient Religion.--Various Symbols.--UNGLAZED POTTERY--_Sun-dried_: Bricks.--Moulds, Stamps, etc.--Vessels.--_Baked Ware_: Its Early Date.--Color of Vessels and Bricks.--Coffins.--Cones.--Figures.--Sepulchral Vases.--Amphoræ and other Vessels.--Decoration.--Græco-Egyptian Pottery.--GLAZED WARE, miscalled Porcelain: Its Nature, and how Colored.--Wall Tiles.--Inlaying of Mummy Cases.--Personal Ornaments.--Images.--Beads, etc.--Vases.--Bowls.--Glazed Schist.--Stanniferous Enamel.