Page:Works of Jules Verne - Parke - Vol 6.djvu/233

 be sufficient to produce all the phenomena of the electric telegraph. Such was the ingenious and very simple apparatus constructed by Cyrus Harding, an apparatus which would allow them to establish a telegraphic communication between Granite House and the corral.

On the 6th of February was commenced the planting along the road to the corral, of posts, furnished with glass insulators, and intended to support the wire. A few days after, the wire was extended, ready to produce the electric current at a rate of twenty thousand miles a second.

Two batteries had been manufactured, one for Granite House, the other for the corral; for if it was necessary the corral should be able to communicate with Granite House, it might also be useful that Granite House should be able to communicate with the corral.

As to the receiver and manipulator, they were very simple. At the two stations the wire was wound round a magnet, that is to say, round a piece of soft iron surrounded with a wire. The communication was thus established between the two poles; the current, starting from the positive pole, traversed the wire, passed through the magnet which was temporarily magnetized, and returned through the earth to the negative pole. If the current was interrupted the magnet immediately became unmagnetized. It was sufficient to place a plate of soft iron before the magnet, which, attracted during the passage of the current, would fall back when the current was interrupted. This movement of the plate thus obtained, Harding could easily fasten to it a needle arranged on a dial, bearing the letters of the alphabet, and in this way communicate from one station to the other.

All was completely arranged by the 12th of February. On this day, Harding, having sent the current through the wire, asked if all was going on well at the corral, and received in a few moments a reply from Ayrton. Pencroft was wild with joy, and every morning and evening he sent a telegram to the corral, which always received an answer.

This mode of communication presented two very real advantages; firstly, because it enabled them to ascertain that Ayrton was at the corral; and secondly, that he was thus not left completely isolated. Besides, Cyrus Harding never allowed a week to pass without going to see him, and