191. DIRECTIONS FOR USING TORTOISE-SHELL JAPAN
Having thus prepared the varnish or japan, clean well the substance which is to be japanned; then lay vermillion, tempered with shell-lac varnish, or with drying oil, very thinly diluted with oil of turpentine, on the places intended to imitate the more transparent parts of the tortoise-shell; when the vermillion is dry, brush the whole over with black varnish, tempered to a due consistence with the oil of turpentine. When set and firm, put the work into a stove, where it may undergo a very strong heat, which must be continued a considerable time; if even three weeks or a month it will be the better. This tortoise-shell ground it not less valuable for its great hardness, and enduring to be made hotter than boiling water without damage, than for the superior beauty and brilliancy of its appearance.
192. TO MAKE CLOTH, SILK &c., WATER-PROOF
Mix equal quantities of alum and acetate of lead, and dissolve the mixture in 1-1/2 gallons of boiling water. When the solution has cooled, remove the supernatent liquid from the sediment, which consists of sulphate of lead, and is ready for use. Any article of dress, when well saturated in this liquid, and allowed to dry slowly, bears the action of boiling water, and does not permit it to pass through, although steam and air penetrate if freely.