Being an economical Vermonter, Barrett went to work in a little wooden shed in the backyard of a Brooklyn foundry.

In this foundry he had seen a unique machine that could be made to mould hot lead around a rope of twisted wires.

This was a notable discovery.
It meant TIGHT COVERINGS.

It meant a victory over that most troublesome of enemies--moisture.

Also, it meant that cables could henceforth be made longer, with fewer sleeves and splices, and without the oil, which had always been an unmitigated nuisance.
Next, having made the cable tight, Barrett set out to produce it more cheaply and by accident stumbled upon a way to make it immensely more efficient.