[Illustration: BOXWOOD POWDER FLASK. OLD GERMAN.]
CARVING CURVED SURFACES: COCOA-NUTS, BOWLS, HORNS, CASKS, TANKARDS, ETC.
Carving concave or convex surfaces, such as the exterior of a horn or the interior of a bowl, is often very difficult work, and though an ingenious artist will readily find out for himself some way to get over such difficulties, it is well to know at once how the work may be done.
HORNS. The first difficulty is to fix the object so as to cut it. A beginner who undertakes to carve such a very hard, slippery, and unmanageable object as a horn, will, if he hold it with one hand while he carves with the other, inevitably damage his pattern or wound himself. It is very dangerous to hold the work in one hand or between the knees. One way to secure such an object is to take a board, nail cross-pieces on it over the ends of the horn so that a portion may be exposed on which to work, and in this manner one can cut with safety. Again, holdfasts and clamps may be employed, but the utmost care should be taken lest these slip away whenever too great pressure is brought to bear on them. A very good means to keep the horn firm is to have a piece of wood fast to the table in which there is a hole, into which the lesser end of the horn fits, while the butt rests, and is fixed, on the table. Having secured it, outline the pattern with a V tool or very small graining-gouge, and then cut away the ground with quarter-flat, and finally with flat gouges. The bent file may be freely used for a horn, and it will be necessary in many places. When bosted, finish with careful touching or fine files and glass-paper.
If you wish to colour the horn, select one which is chiefly white. Take a solution of nitrate of silver, which any chemist will prepare for you. Be very careful indeed how you handle it, for it will burn clothes, carpets, or flesh, and at least stain your fingers for a long time. With a _glass brush_, if you can get one, if not, with a glass point, or pen, or agate point, or wax, apply the acid carefully to the pattern. If you use wood for this purpose it will answer, but it is very speedily consumed by the acid. This will make a yellow, or brown, or sometimes a black stain, according to the strength of the solution, the number of times it is applied, and the hardness of the horn. When the horn is covered with diaper-work, or a great many small figures, or a close pattern, then always put the acid into the hollows, and leave the design in white. A black dye for horn, as well as for metal, is made by combining ammonia with sulphur. It is very malodorous, but is effective. Any chemist will make it, and will also prepare for you the dyes used for ivory and horn. It is better and cheaper for the amateur to buy these than to attempt to make them for himself. In most cases black and brown are the best colours to use.