Dyeing of HORN.—Black is performed by steeping brats in aqua fortis till it be returned green: with this the horn is to be washed once or twice, and then put into a warmed decoction of logwood and water. Green is begun by boiling it, &c. in alum-water; then with verdigris, ammoniac, and white-wine vinegar; keeping it hot therein till sufficiently green. Red is begun by boiling it in alum-water; and finished by decoction in a liquor compounded of quick-lime steeped in rain water, strained, and to every point an ounce of Brazil-wood added. In this decoction the bone, &c. is to be boiled till sufficiently red.
Dr Lewis informs us that horns receive a deep black stain from solution of silver. It ought to be diluted to such a degree as not sensibly to corrode the subject; and applied two or three times, if necessary, at considerable intervals, the matter being exposed as much as possible to the sun, to hasten the appearance and deepening of the colour.