Page:Encyclopædia Britannica, Ninth Edition, v. 13.djvu/548

524 IVORY is quite ancient ; thus Martial contemptuously speaks of a lady of his own time " emptis ossibus indicoque cornu " as having but a poor chance of passing them off as her own teeth. For the use of the dentist elephant ivory was less suitable than that of the hippopotamus or the walrus ; of these two the former was generally preferred. The enamel was chipped off with a chisel, or made to fly off by a judicious application of a blowpipe flame, and the tusk was so cut that the plate might consist as far as possible of the hardest part of the dentine which had formed the front of the tooth. This, carved up to fit the mouth accurately, formed a supporting plate which commonly carried in the front actual human teeth secured by pins, though sometimes the teeth were formed of ivory carved in imitation of teeth, and at the back blocks of hippopotamus or walrus ivory were added for the purposes of mastication. They were called " bone pieces," though there was really no bone used in their construction ; their durability was in no case great, though it varied in the mouths of different persons, and a plate had to be ultimately discarded on account of the ivory getting discoloured, softened, and offensive. For dental purposes walrus ivory was more durable than hippo potamus, but its colour was not so suitable, nor was it so hard. Some specimens of native Indian dental work in ivory exist, but these have probably been copied from plates worn by Europeans. The principal demand for ivory, beyond the purposes already alluded to, arises in connexion with the cutlery trade, very large quantities being used for the handles of pocket and table knives. It is also extensively employed for the handles of walking sticks and umbrellas, for combs, paper knives, and ladies fans, and for measuring rules and mathematical scales. Further, it is in considerable demand for the manufacture of chess and draughts men, for statuettes, rilievo plaques, caskets, and many minor objects of furniture, decoration, and ornament, and for the purposes of inlaying. Dieppe is now a principal centre of the European ivory manufacture. But it is in the East, and especially in China, that ivory is now most highly prized and most elaborately worked into decorative forms. No amount of patience and care appears to be considered excessive among the Chinese for the decorative working of ivory, as is obvious in the extremely minute and delicate workmanship in their lace- like carved open-work trays, while their carved nests of concentric ivory balls are still reckoned among the puzzles of industry. By the Japanese ivory is equally held in esteem, and is decoratively treated in their peculiar mann er in the form of spill cases, medicine boxes, and the elabor ately carved and ornamented nitsuke or large buttons. In India ivory is extensively used in the inlaid work of Bombay, &c., and for furniture decoration generally ; and it is also cut into long slender filaments for making the tails of state chowries or fly-flappers, which, both handle and tail, are in many instances made of ivory. All ivory dust, chips, and pieces unsuited for working are utilized by being converted into gelatin, which they may be made to yield by prolonged boiling, or by being calcined into ivory black. Confectioners are said to make use of ivory dust as a basis for soups, and it forms an excellent colourless size, employed for delicate purposes. When ivory is calcined in a close chamber, in which there is not enough oxygen to burn the carbon into carbonic acid, the organic matrix is burnt into carbon with which remain in the most intimate admixture the lime and mag nesium salts which had previously hardened it. Strange to say, the calcined ivory retains its form and texture not withstanding the destruction of the organic matrix, and specimens sometimes show the engine-turning markings on the cut surface with the utmost distinctness. It is an animal charcoal of great purity, and owes its delicacy and particular properties to the extremely fine division of the carbon particles. When ground up and mixed with appro priate media, it affords both to the oil and the water- colour painter a most valuable black pigment ; it is also used as an ingredient in the fine printing ink used for engravings and etchings. Attempts have been made to manufacture an artificial ivory, but with no very satisfactory result. Billiard balls and other small objects have been manufactured of celluloid, a combination of gun cotton and camphor with ivory dust, which becomes plastic at a temperature of about 280, and when cold is again quite hard and somewhat translu cent. Plaster copies or reproductions of artistic ivories are prepared, under the name of fictile ivories, by casting in very fine plaster of Paris tinted with yellow ochre, and subsequently treating the surface with a mixture of wax and spermaceti or stearine. But it may fairly be said that for the purposes to which ivory is ordinarily applied no substitute approaches it either in beauty or in those other qualities which render it so agreeable and so satisfactory a material for the workman, whether carver, turner, or minia ture painter. See Dr Breyne, Phil. Trans., 1737; Owen, "On the Ivory and Teeth of Commerce," in Journ. Soc. of Arts, 1856 ; Lycll, Principles of Geology ; Boyd Dawkins, CassclVs Natural History, vol. ii. ; C. S. Tomes, Dental Anatomy ; Catalogue of Huntcrion Museum, Royal College of Surgeons ; Holzapft el, Turning and Mechanical Manipulation ; South Kensington Handbooks, Ivories" ; Colonel Yule s Marco Polo ; Du Chaillu, Equatorial Africa; Bur ton, First Footsteps in Eastern Africa ; Tcnnent, Island of Ceylon ; Bowring, Kingdom of Siam ; Westendarp, Mitthcil. dcr geograph. Gcsellschafl, Hamburg, 1878-9 ; Layard s Nineveh and its Remains; Schliemann s flios. (C. S. T. ) IVORY, VEGETABLE. The plant yielding the vegetable ivory of commerce is known to botanists as Phytelephas macrocarpa, Ruiz and Pavon. It is a native of South America, occurring chiefly on the banks of the river Magdalena, Colombia, always found in damp localities, not only, however, on the lower coast region as in Darien, but also at a considerable elevation above (he sea. It is mostly found in separate groves, not mixed with other trees or shrubs, and where travellers tell us even herbs are rarely met with, " the ground appearing as if it had been swept." The plant is severally known as the " Tagua " by the Indians on the banks of the Magdalena, as the " Anta " on the coast of Darien, and as the " Pullipunta " and " Homero " in Peru. It is a stemless or caulescent palm- like plant, the top of which is crowned with from twelve to twenty very long pinnatifid leaves. The plants are dioecious, the males forming higher, more erect, and robust trunks than the females. The male inflorescence is in the form of a simple fleshy cylindrical sparlix covered with flowers ; the female flowers are also in a single spadix, which, however, is shorter than in the male. The fruit consists of a conglomerated head composed of six or seven drupes, each containing from six to nine seeds, and the whole being enclosed in a walled woody covering forming altogether a globular head as large as that of a man. A single plant sometimes bears at the same time from six to eight of these large heads of fruit, each weighing from 20 to 25 ft. In its very young state the seed contains a clear insipid fluid, which travellers take advantage of to allay thirst. As it gets older this fluid becomes milky and of a sweet taste, and it gradually continues to change both in taste and consistence until it becomes so hard as to make it valuable as a substitute for animal ivory. In their young and fresh state the fruits are eaten with avidity by bears, hogs, and other animals. The seeds, or nuts as they are usually called when fully ripe and hard, are used by the American Indians for making small ornamental articles and toys. They are imported into Britain in