"As bearing upon this question it is interesting to note that among the pumps in use around Johannesburg, South Africa, at the beginning of the Anglo-Boer War, there were twelve of a well-known American make, each of which was operated by a 50-horse-power induction motor of American construction with three 15-kilowatt transformers. When the mines were shut down, upon the breaking out of the war, the water rose so rapidly that it was impossible to remove the pumps, motors, transformers, etc., and consequently they remained under 500 to 1,000 feet of water. Two and a half years later, when peace was declared in South Africa, the water in the shaft was pumped out and the electrical apparatus was removed to the surface. Three of the motors were stripped and completely rewound, but to the general surprise of the experts the condition of the insulation indicated that the rewinding might not be absolutely necessary. Accordingly the other nine motors were thoroughly dried in an oven and then soaked in oil. After this treatment they were rigidly tested, proved to be all right, and were at once restored to regular service in the mine. The transformers were treated in the same manner as the motors, with equally gratifying results. "An interesting illustration of the flexibility and adaptability of electric motors for pumping purposes is furnished by the Gneisenau mine, near Dortmund, Germany, where a very large electric mining plant was installed in 1903. In this instance the pump is located more than 1,200 feet below the surface, and the difficulties of installing the apparatus were so great, on account of the small cross section of the shaft, that it was necessary to build up the motor in the pumping chamber, the material being transported through the wet shaft and the winding of the coils being performed _in situ_. "An interesting use of the electric pump associated with the telephone in connection with mining is noted by Mr. W. B. Clarke. In one coal mine, where an electric pump is located in a worked-out portion of the mine, the circuits are so arranged that the pump is started from the power house, some distance away. Near the pump is placed a telephone transmitter connected to a receiver in the power house. To start the motors, or to ascertain whether the pumps are working properly, the engineer merely listens at the telephone receiver, without leaving his post." ELECTRICITY IN COAL MINING