Every mile of it, doubled, weighed two hundred pounds and cost thirty dollars.

On the long lines, where it had to be as thick as a lead pencil, the expense seemed to be ruinously great.

When the first pair of wires was strung between New York and Chicago, for instance, it was found to weigh 870,000 pounds--a full load for a twenty-two-car freight train; and the cost of the bare metal was $130,000.

So enormous has been the use of copper wire since then by the telephone companies, that fully one-fourth of all the capital invested in the telephone has gone to the owners of the copper mines.
For several years the brains of the telephone men were focussed upon this problem--how to reduce the expenditure on copper.

One uncanny device, which would seem to be a mere inventor's fantasy if it had not already saved the telephone companies four million dollars or more, is known as the "phantom circuit." It enables three messages to run at the same time, where only two ran before.