have set themselves the task of working out complete systems of apparatus along the lines laid down by him. The Westinghouse Company, which early secured control in this country of Mr. Tesla's inventions, has developed a system using a two-phase current, while the other considerable American company, the "General Electric" has worked out a system employing a three-phase current, which form of current has also been adopted by the Allgemeine Elektricitäts Gesellschaft of Berlin. All these companies make an exhibit of this class of apparatus at the exposition, arranged to show the system in operation. The exhibits of the two chief American companies are substantially the same, differing mainly in the character of current used. Each shows the generation of multiphase currents, their transmission to the point of distribution, and their utilization in alternating and direct current apparatus.
How completely the problem of the distribution of electrical power over long distances has been solved by this system, and to what extent we may expect to see it pass into commercial use, experience alone can determine. Disregarding its future utility, when we will perforce be driven to the utilization of natural powers, and looking only to the immediate present, it is not difficult to' see that its adoption will be primarily determined by the cost of operating local steam plants. Where fuel is abundant, and hence cheap, there will be little inducement to resort to sources of power at a distance, but in all situations in which this condition does not obtain, and water power is to be had within a reasonable distance, electric power transmission will find a field, and one which will constantly widen with experience. While the utilization of water powers is the most obvious use for electric power transmissions, and certainly its most immediate one, it is quite possible that it will not prove to be the only one. As is well known, a large part of the cost of coal to the consumer is the expense of hauling it from the mines. It has been often pointed out that if the coal could be burned at the pit's mouth and its energy transmitted to the place of use there might result a great saving, but any economical method of doing this has heretofore been wanting. The suggestion has many times been made to convert the coal into gas and distribute this, but the cost of piping has heretofore rendered this method of eliminating the cost of railroad carriage impracticable. It would seem, however, to be quite within the range of practical possibilities to find in electric transmission an efficient and economic method.
[To be concluded.]