Page:Popular Science Monthly Volume 24.djvu/767

Rh This speed is realized with ease, but a much greater rate could be attained, if it were allowed.

It can hardly be hoped, however, that such a simple system as this could be adopted for running cars in the streets of a city, for other difficulties would be introduced. The fact that the rails in the streets must, of necessity, be close to the surface of the ground, and that they are to be stepped upon by men and horses, shows at once the necessity of having the conductor out of the way, and the danger of having the current traverse the rails. At the Electrical Exposition held at Paris in 1881, Messrs. Siemens & Halske had an electric rail-way in operation, in which a third or auxiliary conductor was used; but this ran along on posts like a telegraph-wire, the current being conveyed from this conductor to the motor by means of a flexible conductor, which was connected at one end with the motor on the car, and at the other with a contact-carriage, or trolly, which was drawn along the conductor by the car as it advanced.

In mines, in tunnels, and in all places where the smoke of burning coal is objectionable, it would seem that the electric railway possesses unrivaled advantages. As the motor gives off no smoke, makes little noise, occupies but a small space, and does not have to carry its own