A double track of wires is made to carry three talk-trains running abreast, a feat made possible by the whimsical disposition of electricity, and which is utterly inconceivable in railroading.

This invention, which is the nearest approach as yet to multiple telephony, was conceived by Jacobs in England and Carty in the United States.
But the most copper money has been saved--literally tens of millions of dollars--by persuading thin wires to work as efficiently as thick ones.
This has been done by making better transmitters, by insulating the smaller wires with enamel instead of silk, and by placing coils of a certain nature at intervals upon the wires.

The invention of this last device startled the telephone men like a flash of lightning out of a blue sky.

It came from outside--from the quiet laboratory of a Columbia professor who had arrived in the United States as a young Hungarian immigrant not many years earlier.

From this professor, Michael J.
Pupin, came the idea of "loading" a telephone line, in such a way as to reinforce the electric current.