As many of my readers may wish to line their snuff-boxes with tortoise-shell, I think it needful to give some instructions in the best method of doing it. Cut the shell into very thin leaves with a sharp fine saw, then divide these into the size you wish for the inside of the snuff-box, leaving a very little extra for the joint. Take a new rough file, and scrape away a little of the two ends of the narrow strip of shell, so that they can lie one upon another, and fit so closely that the aperture is hardly perceptible. Plunge the tortoise-shell into warm water for a few minutes, and it will become quite soft. Have ready on the lathe a piece of wood a little less in circumference than the inside of the box, and perfectly round and smooth. While the shell is soft, place the joints together, wrap a wet piece of linen tightly over them to hold them fast, and press them firmly together with the finger and thumb. Then heat a pair of tongs to a proper heat, (which is known by trying them on writing paper; if they brown it, they are too hot; if they only turn it yellow, they are right,) and with them compress the joint of the tortoise-shell. The water, the heat, and the pressure united, will make the two parts join firmly. When finished thus far, file away any roughness that may remain, and steep the shell into hot water till quite soft, then slip it upon the piece of wood before mentioned, and see if it fits it perfectly; if not, try with pressure to give it the requisite shape; and if this does not succeed, take the wood out of the lathe, leaving the tortoise-shell upon it, and hold them over a brazier, turning them frequently and quickly between the hands, that the heat may equally penetrate all the parts; then strike the side that bulged out with a mallet, and with a little care it will soon assume the required form. You may finish it on the lathe, observing only to place it so that the tool does not catch the lap of the joint, which might cause it to open; and when you take it off, plunge it in cold water to make it retain its form.
TO FINISH THE SNUFF-BOX.
Make your box and lid of hard, well-seasoned wood; hollow them out, and polish the insides, only omitting to cut the lip upon which the lid fits, and which will be formed by the tortoise-shell. As you hollow out the box and lid, keep fitting in the shell, that you may not make them too large; when it slips in rather tight, take a point tool and cut some circles on the inside of each; (this is done to enable the glue to hold firmly.) Now, take the tortoise-shell and file that part that is to be cemented to the box, so as to make it rough. Take a pair of compasses, in one end of which is a sharp knife, set them to the exact size of the inside of the bottom and lid, then place them on a piece of tortoise-shell, and cut out the two round pieces. Melt some glue till rather liquid, thicken it with vermilion, lay a coat on the inside of the top and bottom of the box, and press in the two circles of tortoise-shell; in the same manner glue in the sides, leaving the lip (upon which the lid is to fit) standing up above the bottom part of the box. Leaving the glue to harden for a day, then replace the work on the lathe, turn the inside quite even, and polish it with pounce powder and oil, then with tripoli powder and water. Should the lid, when finished, become too small for the box, dip it for a minute in boiling water, fit it on to a piece of wood the exact size, and leave it there to harden.
HORN TO IMITATE TORTOISE-SHELL.
Dissolve three ounces of potash in a pint of boiling water. Let it boil for a quarter of an hour, then pour it into a basin capable of holding about as much again, and in which you have put half a pound of quick lime, stir it well, and when the latter is slacked, add three ounces of red lead and one ounce of vermilion.
When the whole is of the consistency of thick soup, dip a thin pointed stick into it, and lay the drops it will take up upon a piece of horn in those parts required to be coloured, leaving those that are to be transparent. When quite dry, clean the whole with a wet sponge, and you will find it will greatly resemble tortoise-shell.
MASTIC USED IN TURNING IVORY VERY THIN.
To turn ivory as thin as writing paper, so as to render it quite transparent, is very difficult to accomplish, but is much admired when done, and shows the skill of the artist. To enable the ivory to bear the action of the tool without splitting, the following mastic has been found very useful, both for strengthening it and for giving a deep colouring, by which means the thinness is more perceptible. Some turners wet the ivory for the latter purpose, but as when wet it is quite transparent, and thickens again when dry, the mastic will be found much preferable.
Take some lamp or ivory black in powder, and strain it through a fine sieve, so as only to retain the finest parts. Steep these in water to free them from any impurities. After lying in it a few minutes, pour off the water, and make some glue very hot, mix it with the lamp black till of the consistency of oil paint. This mastic must be kept warm near the fire, and when you have sufficiently hollowed out the vase, or whatever you wish to turn, very thin, shape the outside a little: then dip a large camel’s-hair brush in the warm varnish and lay a thick coat all over the inside; let this dry, put on another, and repeat the process till sufficient strength is obtained. You may now, without fear or danger, work your ivory as thin as possible, and ornament it with the cutters and drill. Without this mastic it would not, when transparent, bear the force of these tools.
When the work is all finished and carefully polished, take it off the lathe, and put it in a basin filled with warm water. After a few minutes’ immersion, take it out, and plunge it in clean water, shaking it gently. This will make the mastic dissolve and leave the ivory. Renew the warm water frequently, as leaving it in the blackened liquid might injure the colour of the work.