“Yes, that’s right.”

“The wires go out from the cave and fence in a circle of level ground a hundred yards in diameter; they make twelve independent fences, ten feet apart — that is to say, twelve circles within circles — and their ends come into the cave again.”

“Right; go on.”

“The fences are fastened to heavy oaken posts only three feet apart, and these posts are sunk five feet in the ground.”

“That is good and strong.”

“Yes.

The wires have no ground-connection outside of the cave. They go out from the positive brush of the dynamo; there is a ground-connection through the negative brush; the other ends of the wire return to the cave, and each is grounded independently.”