Varnish

IMG:p599_4.png:Chinese characters c?i'i, is the sap of ffhiis vernicifera, a tree whose principal habitat is in Kueichou and Ssuch'uan. It grows in other provinces, such as Chekiang, but in no great abundance. Its altitudinal range is from 3,000 to 7,500 feet, the optimum being 4,000 to 5,000 feet. The port of Ningpo was one of the first ports opened to foreign trade, and probably foreigners first came into contact with the varnish there, and called it "Ningpo" varnish, a name which it still bears in the trade. It is largely used in lacquer v.-ork and nearly all the foreign export goes to Japan. Hankow is the chief market for the supply, followed by Ichang and Yochow; other ports supply very little. The annual inter port exportation averages 26,000 pitjuls, of which half goes abroad. HosiE states IMG:p599_5.png:Chinese characters on Ssuch'uan, p. 29) that the sap is obtained from incisions in the bark of the tree, which are made first when the tree is seven years old, and not again for seven years. The sap, which on i uing from the tree is of a greyish white colour, must not be exposed to the air, which hastens its inherent tendency to become black. A layer of paper is placed over the ve els containing it to ensure this. Adulteration is detected by the smell, and by the fact that pure varnish if held up and made to drop, will remain in an unbroken string, but the string will break if the varnish has been mixed with oil. If adulterated with oil, varnish placed on paper will "run," the paper absorbing the oil. A peculiarity of "Ningpo varnish" is that it hardens only in a moist atmosphere and remains in a tacky condition if exposed to sunlight and heat, the e entials in hardening copal varnish. It should therefore only be applied during cloudy weather when the atmosphere is surcharged with moisture. For indoor work its drying is facilitated by hanging about the room cloths saturated in water. The only change which takes place in the composition of the lacquer in drying at ordinary temperatures is the slow absorption of oxygen, which is attributed to an obscure chemical reaction depending on the presence of a compound of manganese with a proteid-like substance. Red varnish is obtained by the admixture in certain proportions of wood oil and cinnabar; yellow, by the admixture of wood oil and powdered orpiment. The export in 1916 was pels. 15,619, value- Tls. 788,658.