It was the best-talking cable that had ever been harnessed to a telephone.
What Barrett had done was soon made clear.

By wrapping the wire with loose paper, he had in reality cushioned it with AIR, which is the best possible insulator.

Not the paper, but the air in the paper, had improved the cable.

More air was added by the omission of the oil.

And presently Barrett perceived that he had merely reproduced in a cable, as far as possible, the conditions of the overhead wires, which are separated by nothing but air.
By 1896 there were two hundred thousand miles of wire snugly wrapped in paper and lying in leaden caskets beneath the streets of the cities, and to-day there are six million miles of it owned by the affiliated Bell companies.