g
motion causes it to revolve. As it revolves it screws down a detonator
which comes in contact with the charge at ten, fifteen, twenty, or forty
or more feet as designated by the hand of an indicator on the bomb. The
hand of this indicator is, of course, set by the officer before the bomb
is released either from a gun or from tracks along the deck.

Then there have been a number of tricks; some of them Yankee tricks,
some of them the creatures of the equally fruitful British tar. One day
in the North Sea a British patrol-vessel came across a trawler. It
resembled the ordinary British trawler, but there were points of
difference, points that interested the inquisitive--and
suspicious--commander of the war-vessel. Chiefly there were a lot of
stores upon her deck. She flew the Norwegian flag, and her skipper said
he was neutral. But the British commander decided to take a chance. He
arrested the crew, placed them in irons, and manned the trawler with a
crew of French and English navy men.

The trawler hovered about in the same locality for three days, and then
one morning, lo and behold, a periscope popped up close alongside.
Seeing the waters clear of enemy ships, the U-boat came to the surface
and frisked blithely up to the trawler. She was greeted by a shower of
machine-gun bullets, and surrendered without ado. There was really
nothing else for the surprised skipper to do. For when he had last seen
that trawler she was the parent ship of the submarine flotilla operating
in that vicinity. In all, before the week was over, that trawler had
captured six submarines without the loss of a life, and no one injured.

Thereafter the parent-ship trawler was seized whenever the British could
capture one, and the same expedient was tried. But after a time the
Germans became wary of approaching parent-ships until they were
convinced that their parenthood was more real than assumed.

Then one day after the Americans arrived a three-masted schooner was
commandeered. They put a deck-load of lumber on her; at least it was an
apparent deck-load. It was really a mask for a broadside of 3-pounder
guns, different sections of the deck-load swinging open to admit of free
play of the guns, as levers were pulled.

The schooner, commanded by a Maine skipper and his crew, was turned
loose in the North Sea. Astern towed a dingy; from the taffrail flew the
American flag. Before long out popped a submarine. Aha! A lumber-laden
vessel--American