Hard vulcanized rubber, termed vulcanite, and sometimes ebonite, is made into a great many small articles, such as combs, chains, bracelets, boxes, penholders, paper-knives, knife-handles, buttons, etc., as a substitute for materials like horn, bone, ivory and jet. Like these substances themselves, it is formed into various objects by molding, cutting, carving, polishing and other processes. Vast numbers of these articles are now sold. The black color of vulcanite ornaments has still a tendency to turn gray, but the brittleness which was a fault of combs made of it a few years ago has been overcome.
Manufactures from india rubber turned out from the factories of the United States in 1914 amounted to a value of $300,994,000. Of this total a value of $53,822,000 was in the form of boots and shoes. So great is the demand for India rubber, for use in manufacturing, that not only has the importation grown from 2,000,000 pounds in 1862 to over 200,000,000 pounds an nually at the present period, but in addition to this the forests of the East Indies are called upon for several million pounds annually of a substitute for gutta-percha, known as °gutta joolatong,* while at the same time the high ways and byways of Europe and other coun tries are ransacked for cast-off rubber manu factures from which the rubber is °reclaimed* and re-used in conjunction with the new rubber from the forests of Brazil, Africa and the East Indies.
The industry of importing and india rubber for re-use in manufacturing is a comparatively new one, and while it utilizes large quantities of worn-out rubber boots and shoes and other articles of this character from the scrap heaps of the United States, it has only taken in other parts of the world in recent years.
Importation.— The effect of the Great War in Europe on the rubber importations of the United States has been remarkable. In 1913, the last year in which the figures can be con sidered as normal, the quantity of rubber im ported was 113,384,359 pounds, valued at $90, 170,316. In the fiscal year ended 30 June 1916, the importation was 267,775,557 pounds, valued at $155,044,790. Of the great total, 125,532,067 pounds came direct from the East Indies; 72, 459,408 pounds from England — part of this be ing East Indian and Part South American pro duction; 54,968,227 pounds from Brazil and 6,265,387 pounds from Peru and other South American countries; and 4,599,042 pounds from Mexico and Central America. In addition, the United States imported in the fiscal year 1914– 15, 3,188,449 pounds of gutta-percha (1,204,406 pounds in 1913), nearly all from Straits Settle ments; in 27,858,335 pounds of gutta-joolatong (45,345,338 pounds in 1913), of which 90 per cent came from Straits Settlements; 2,816,068 pounds of guayule rubber from Mexico (10, 218,191 pounds in 1913) ; and 16,371,573 pounds of scrap or refuse for remanufacture (43,385, 456 pounds in 1913), principally from Canada and England.
See also CAOUTCHOUC; RUBBER MANUFAC TUREs, AMERICAN; RUBBER TREES.
Consult Brown, H., Its Source, Cultivation and Preparation' (London 1914) ; Pearson, H. C., (Rubber Machinery' (New York 1915); Potts, H. E., The Chemistry of the Rubber Industry' (London 1912) ; Schidro witz, P., (Rubber' (London 1911) ; Seeligman, T. (and others), India Rubber and Gutta (London 1910) ; (Reports of the Fourth Rubber Congress> (London 1914).