Page:Ballantyne--The Battery and the Boiler.djvu/29

 the metals, are called conductors; those of the second class, embracing, among other things, all resinous substances, are styled non-conductors. Now, water is a good conductor. So that although the Spark will stick to his wires when insulated on telegraph-posts on land, he will bolt from them at once and take to flight the moment he gets under water. This difficulty was overcome by coating the wires with gutta-percha, which, being a non-conductor, imprisoned the Spark, and kept him, as it were, on the line.

A copper wire covered in this manner was successfully laid between England and France in 1860. When tested, this cable did not work well. Minute imperfections, in the form of air-holes in the gutta-percha, afforded our Spark an opportunity to bolt; and he did bolt, as a matter of course—for electricity has no sense of honour, and cannot be trusted near the smallest loop-hole. The imperfections were remedied; the door was effectually locked, after which the first submarine cable of importance was actually laid down, and worked well. French and English believers turned up hands and eyes in delighted amazement, as they held converse across the sea, while unbelievers were silenced and confounded.

This happy state of things, however, lasted for only a few hours. Suddenly the intercourse ceased.