=Nickel in Veins.=--Nickel occurs with other metals, precious or semi-precious, in some vein deposits and is recovered as a by-product in the treatment of ores from them. It is notably present in the deposits at Cobalt, Ontario, and has been found in vein deposits in the United States, France, Germany, Austria, Mexico and South America. Several hundred tons are recovered annually in the refining of copper produced in the United States. Related to the vein deposit type of nickel-bearing ore are the galena deposits disseminated through dolomite in southeastern Missouri. Iron, copper, nickel, and cobalt sulphides occur with the galena. Years ago nickel was recovered electrolytically from matte from these ores. DEVELOPMENTS AND CHANGES IN KNOWN GEOGRAPHICAL DISTRIBUTION In 1900 New Caledonia supplied 65 per cent. of the world’s production and Ontario 35 per cent. Since then the world’s production has increased six-fold, and Ontario, by the end of 1916, was producing 80 per cent. of the whole. This shows the trend of the industry. Recent discoveries of ore in the Sudbury district and construction of new smelters and refineries in Ontario to treat the ores indicate an increasing dominance of the industry by that district. New Caledonia has not the large ore bodies and is too far away to compete favorably with Ontario, though work will continue there. [Illustration: FIG. 7.--Refined nickel produced from the ores of New Caledonia and Ontario, for five-year periods; the amounts are for the calendar year indicated.] Statistics of production and ore reserves in Ontario and New Caledonia are shown graphically in figures 7 and 8. Isolated nickel ore bodies of the sulphide type--that is, segregations from basic igneous rocks, as at Sudbury--have been found in a number of widely separated places. There is a distinct probability that others exist and may be discovered. Such undiscovered deposits might even contain more accessible ore, in the aggregate, than the total of the mined and unmined ores of the Sudbury district, but in the light of present knowledge this seems a remote possibility. Other deposits of the New Caledonian and Cuban types will probably be discovered, but it is doubtful if as large deposits of those types remain to be found. In these the nickel has remained in the material left as residuum from the partial or complete weathering by solution of the original nickeliferous rock. This material lies at the surface and covers relatively broad areas. Bodies of it are therefore not usually difficult of discovery. They seem to be found most abundantly in warm latitudes, where solution weathering has most easily gone on under conditions favorable for preservation of the residuum. [Illustration: FIG. 8.--Nickel production, and nickel content of reserves, in Ontario, New Caledonia, and Norway.]