y along one class of substances, he cannot,
or will not, run along others. Substances of the first class,
comprising 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 1850. 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. The telegraphists at both ends
energised with their handles and needles, but without any result. The
cable was dumb. Our Spark had evidently escaped!

There is no effect without a cause. The cause of that interruption was
soon discovered.

Early that morning a French fisherman had sauntered down to the port of
Boulogne and embarked in his boat. A British seaman, having nothing to
do but smoke and meditate, was seated on a coil of rope at the time,
enjoying himself and the smells with which that port is not unfamiliar.
He chanced to be a friend of that French fisherman.

"You're early afloat, Mounseer," he said.

"Oui, monsieur. Vill you com'? I go for feesh."

"Well, _wee_; I go for fun."

They went accordingly and bore away to the northward along the coast
before a light breeze,--past the ruined towers which France had built to
guard her port in days gone by; past the steep cliffs beyond Boulogne;
past the lovely beach of Wimereux, with its cottages nestled among the
sand-hills, and its sil