DIAMONDS COMMERCIALLY	39
	portant end of the diamond business is largely in the hands of the Jews in this country, is explained. The diamond has been a great commercial influence, not only by opening new territory and thereby largely increasing the demand for other products to supply the needs of new and incrtasing commodities, but it has become a valuable assistant in the development of im­portant modern staples of commerce. Bort and carbo­nado, the semi-transparent and crypto-crystalline dia­monds, though useless for gem purposes, are used extensively in processes of manufacture where great resistance to wear and tear is requisite. These are used to saw marble, granite, and other hard stones; to drill and bore in mining and similar operations, and from the refuse of gem crystals are made draw-plates for draw­ing the fine metal wires so necessary for electrical supplies. The supreme hardness of the material enables the manufacturer to draw great lengths of wire without the slightest variation of gauge through the enlargement of the holes, as would be the case with a plate of hard metal. It is a curious fact worthy of attention in pass­ing, that, as needs arise in the evolution of man's mechanical skill, Nature presents some new form of supply adequate. Simultaneous with the tremendous development of mining, tunneling, and the application of scientific discoveries to practical purposes during the past fifty years, the diamond fields of Africa and the carbonado fields of Bahia, containing vast quantities of material suitable for the requirements of those condi­tions, were discovered and developed. Similarly, the yield of gem stones has been abundant for the demands of an era of unprecedented prosperity. The abundance