His first successful invention in this field was a dynamo to furnish light for railroad trains. From this he was led to the invention of a dynamo capable of doing effective work at much lower speed than that usually employed, and this has proved to be his most valuable achievement. Some improvements in winding the armatures have also been accepted as valuable and adopted by other manufacturers. In connection with storage batteries Mr. Eickemeyer has also done a good deal of interesting work. But he is chiefly known to the electrical world as the inventor of a most useful dynamo for power purposes. For the last forty years he has been one of the men who have most aided in the growth of Yonkers, taking great interest in all questions pertaining to its government and school system. He was married in 1856 to Mary T. Tarbell, of Dover, Me., and his eldest son, Rudolf Eickemeyer, Jr., is associated with him in business. GEORGE WESTINGHOUSE, JR., AND THE AIR-BRAKE. [Illustration: George Westinghouse, Jr.] George Westinghouse, Jr., to whom is due the railroad air-brake, and who was also largely instrumental in revolutionizing Pittsburgh by the introduction of natural gas, was born at Central Bridge, in Schoharie County, N.Y., in 1846. His father was a builder and, later, superintendent of the Schenectady Agricultural Works, and it was in the shops of these works that the boy found his vocation. Before he was fifteen he had modelled and built a steam engine. The war took him away from work in 1864, but when that was over he returned to Schenectady and, although yet in his teens, he began to attempt improvements upon every device that presented itself. Sometimes he was successful. Among one of his first valuable achievements was a steel railroad frog that resulted in a good deal of money and some reputation. This was in 1868. While in Pittsburgh making his frogs, which sold well, he one day came across a newspaper account of the successful use of compressed air in piercing the Mont Cenis tunnel. His success in the field of railroad appliances had led him to study the question of better brakes, and the suggestion of compressed air came to him as a revelation. To stop a train by the old methods was a matter of much time and a tremendous expenditure of muscular energy by the brakeman, whose exertions were not always effective enough to prevent disaster. Westinghouse consulted one or two friends, who were inclined to ridicule the idea that a rubber tube strung along under the cars could do better work than the men at the brakes. Fortunately, he was able to make the experiment, and the air-brake was speedily recognized as one of the important inventions of the century.