Tortoiseshell is supplied almost entirely by the carapace or shell of the " hawksbill" tortoise, which frequents the warm waters of the East and West Indies. The shell always consists of thirteen plates, and these are generally torn apart and tied together for convenience of carriage. Tortoise-shell sells at from 20s. to 21s. a pound, and very often a single large plate will be more than 1 lb. in weight. Much time and money have been expended in endeavours to find a, means of melting tortoiseshell, but without success, and so it is joined by a kind of welding process. The edges to be united are shaved and scraped to a feather edge, and laid together with a piece of fresh shell upon them; the whole is then subjected to a moist heat (as of hot water), which softens it, and it is theu put under great pressure until the parts are united, after which the surplus thickness is removed as waste. Another method of welding tortoiseshell is to first file It clean, and lap one edge over the other, taking care that no grease remains, wet;the joint with water, and hold it in a hot pair of pincers, so constructed as to cover 4 in. or 5 in. of the joint. Kemove the pincers and apply more water, and the joint will be found secure. The pincers must not be so hot as to burn the shell.

In some cases it is possible to form a good joint by cementing, and then one of the following cements is used. (1) Dissolve in 125 parts of 90 per cent, alcohol:W parts of shellac and 10 parts of mastic, and add 2 parts of turpentine. (2) Dissolve in 58 parts of 90 per cent, spirit of wine 5 parts of mastic and 15 parts of shellac, and add 1 part of turpentine. In making tortoiseshell combs, two are cut out of one strip, and while soft a deep zigzag cut is made down the centre of the strip to form the teeth of the two combs, which thus fit closely to each other. As quickly as possible the two parts thus divided are torn asunder, as in a few seconds they would reunite. This is a difficult operation, and liable to prove costly if much waste results. To form the knobs and other raised parts seen on fancy tortoiseshell combs, the shell is heated, and while in a pliable state is gradually worked and pressed up into a mould of the required form, and subsequently smoothed and polished. Material which has been thus treated cannot be reshaped if broken, for on re-heating it takes its original form, from which it cannot be altered. Combs are usually made of more than one thickness of shell, and as many as six thicknesses are sometimes welded together.

When patterns are to be carved into the work, extra thicknesses are welded on. Shell from the claws is used when a streak of unusually light colouring is required, and the under or " belly " shell, which is almost transparent, is used for the amber shell-work. In finishing tortoiseshell, it is first scraped, and then polished with pulverised charcoal and water on a woollen cloth perfectly free from grease. This is followed by water and washed chalk or whiting, the article being moistened with vinegar. Finally it is hand-rubbed with dry whiting or rottenstone. By another method of polishing, the horn is scraped smooth and level and is rubbed with very fine glasspaper or Dutch rushes, and afterwards with felt dipped in finely powdered charcoal and water. After rubbing with rottenstone or putty powder, it is finished with a soft washleather damped with sweet oil, or is rubbed with nitrate of bismuth applied by the palm of the hand.