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Page:Popular Science Monthly Volume 24.djvu/766

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746
THE POPULAR SCIENCE MONTHLY.

current going to the locomotive by one rail and returning by the other; while, in other systems, a third or auxiliary conductor is used. To collect the current and pass it through the motor, two strips of copper or brass in the circuit of the motor extend from the locomotive and press upon the conductors; so that, as the car advances, these keep up a scraping contact. Two wheels in circuit with the motor are also sometimes used as collectors.

The distinction of being the first to conceive and suggest the idea of an electric railway seems to belong to Dr. Werner Siemens, of the celebrated firm of Siemens & Halske, which has been more identified with the practical development of electrical science than any other firm in the world. In pursuance of his idea, Dr. Siemens constructed the first electrical railway at Berlin in 1879.

In this railway, whose length was about three hundred and fifty yards, and whose gauge was about three feet and three inches, a third or auxiliary conductor was used to convey the current from the dynamo to the motor. This conductor lay between and parallel to the other two rails, and the current was taken from it by a metal brush connected with the motor, which extended from the car and pressed upon the conductor. After going through the motor, the current went to both rails and by them back to the dynamo, the rails acting as the "return." The motor was placed upon a car, attached to which were three other cars, the first thus acting as the locomotive. Such was the interest excited by this novel system of transportation, and such its success, that it continued in operation for several months, and carried thousands of people, the money received for fares being contributed, it is said, to charitable institutions in the city.

The success of this experimental railway led the Messrs. Siemens to plan another upon a more extended scale; and they applied to the authorities for permission to build an elevated road in Berlin, six miles long, on which single cars, each fitted with an electro-motor, were to be run by means of electricity. Permission to do this was refused, on account of the inconvenience to the inhabitants which would result from the structure; but, ultimately, leave was given the same firm to build a surface electric railway from Lichterfelde, one of the suburbs, to the military academy. This railway is still running, and its operation has throughout, for more than two years, been of the most satisfactory character. No auxiliary conductor is used, the current going from the dynamo along one rail, through one of the wheels, through the motor, through a wheel on the opposite side of the car, and thence to the other rail, which acts as the "return." No trains are made up, but each car is fitted with an electro-motor, which lies beneath the flooring. As the authorities declare these cars to fall under the same heading as tram-cars, the speed at which they may be run is limited by law to twelve miles per hour.