CAOUTCHOUC

n. Ka3-ut'chuk. Said to be from the South American words\cate, a tree, and chu, juice. Lat., resina elastic a (seu cayennensis), gummi, elasticum. Fr., c. [Fr. Cod.], gomme elastique. Ger., Kautschuk. elastisches Gummi, Ledergummi, Federharz. It., cautchuc. Sp., goma elastic a. India-rubber, rubber, gum elastic, gum; a substance obtained by drying the milky juice of various plants, particularly, according to the Fr. Cod., of the Castilloa elastic a and other artocarpaceous trees, the Hevea fiuayanensis (Siphon i a elastic a), Hevea lutea, Hevea (Siphon i a) bras i liens is, and Hevea, spruce an a, and of several species of Apocynaceo3, especially of the genera Hancornia and Vahea. Other trees furnishing c. are the Ficus elastic a ( Urostigma elasticum), Ficus indica, Ficus retigiosa, Urostigma Vogelii, Landolphia gummifera, Landolphia florida. Urceola elastic a, Urceola esculent a, Willoughbeia edulis, and various plants of the Apocynacece, Asclepiadacece, Urticaceoz, and Euphorbiact.-ce. It forms variously shaped, tough, highly elastic, amorphous, somewhat porous ma es, black or dark-brown externally and white or brownish within, of a sp. gr. varying from 0'92 to 0'96; insoluble in water, softened by treatment with hot alcohol; partially soluble in ether, in chloroform, in benzene, in oil of turpentine, and in carbon disulphide, the undi olved portion forming a soft, jelly-like ma , while that in solution is highly adhesive and ductile. The best solvents are chloroform, carbon disulphide, and caoutchouc in. C. melts at 125 C., and is readily inflammable, burning with a smoky flame. Chemically, it is a hydrocarbon, or a mixture of hydrocarbons, of the empirical formula C2oH3.,. It is used in surgery and in the arts wherever elasticity or protection from air or liquids is desired, as in elastic stockings, elastic bandages, protective coverings, etc. Combined with sulphur and other ingredients, it is used for making tubing and innumerable other articles. [A, 301; B, 2, 81, 95, 113.] See Vulcanized c. and Hard RUBBER. Bornean c., Borneo c. C. obtained from Borneo, from different species of Urceola. [B, 81, 275.] C. des Papayan a is (Fr.). A variety derived from the Lobelia (Siphocampylus) caoutchouk. [B, 93.] C. dur (Fr.), C. durci (Fr.). See Hard RUBBER. C. mineral (Fr.). See ELATERITE. C. soufre (Fr.), C. volcanise (Fr.), C. vulcanise (Fr.). See Vulcanized c. and Hard RUBBER. Ceara c. C. obtained from the Manihot Glaziovii. [B, 81.] Chittagong c. C. derived from the WiUoiif/hbeia edulis and allied apocynaceous plants. [B, 81.] East Indian c. C. derived from the Ficus elastic a. [B, 275.] Empyreumatic oil of c. See CAOUTCHOUC IN. Hardened c. See Hard RUBBER. Indian c.-tree. The Ficus indica. [B, 172.1 Madras c. C. derived from the Euphorbia catimandoo. [B, 275.] Mangabeira c. C. derived from the Hancornia speciosa. [B, 81.] Mexican c. See Mexican CHICLE. Mineral c. See ELATERITE. Oil of c. See CAOUTCHOUC IN. Panama c. C. derived from the Castilloa elastic a and the Castilloa mark ham i an a. [B, 275.] Para c. One of the best varieties, derived from the Siphon i a elastic a (Hevea guianensis), a tree indigenous to Guiana and northern Brazil. [B, 81.] Penang c. See Borneo c. Sulphured c., Vulcanized c. Fr., c. vulcanise (ou soufre). Ger., vulkanisirtes Kautschuk. Vulcanized rubber; c. mixed intimately with sulphur and heated. It is not affected by the ordinary solvents of c., and does not, like the latter, lose its elasticity at low temperatures. When of good quality, it preserves its properties for a long time, but the poorer qualities soon become worthle . It is injured by contact with oil, but it is said that the injury may be repaired by washing with ammonia-water. It is largely used in the manufacture of most articles for which c. is suitable. By long-continued vulcanization at a high temperature, it is converted into hard rubber (q. v.). [B, 2, 81.] [s. 65]