Dr. Staines got from the carpenter some sheets of zinc and spare copper,
and some flannel: these he cut into three-inch squares, and soaked the
flannel in acidulated water. He then procured a quantity of bell-wire,
the greater part of which he insulated by wrapping it round with hot
gutta percha. So eager was he, that he did not turn in all night.

In the morning he prepared what he called an electric fuse--he filled
a soda-water bottle with gunpowder, attaching some cork to make it
buoyant, put in the fuse and bung, made it water-tight, connected and
insulated his main wires--enveloped the bottle in pork--tied a line to
it, and let the bottle overboard.

The captain and officers shook their heads mysteriously. The tars peeped
and grinned from every rope to see a doctor try and catch a shark with
a soda-water bottle and no hook; but somehow the doctor seemed to
know what he was about, so they hovered round, and awaited the result,
mystified, but curious, and showing their teeth from ear to ear.

"The only thing I fear," said Staines, "is that, the moment he takes the
bait, he will cut the wire before I can complete the circuit, and fire
the fuse."

Nevertheless, there was another objection to the success of the
experiment. The shark had disappeared.

"Well," said the captain, "at all events, you have frightened him away."

"No," said little Tadcaster, white as a ghost; "he is only under water,
I know; waiting--waiting."