l set off the fuse that sets off the tremendous charge of high
explosive; and this may knock a hole in the side big enough to drive a
street car through. But there are many more misses than hits.

Yet the German and Austrian raiders, mines, and submarines sank fifteen
million tons of shipping, which is not far short of a third of all the
merchant tonnage in the world; and the submarines sank more than the
mines and raiders sank together. (Ships are measured by finding out
how many cubic feet of space they contain and counting so many feet to
the ton. Thus you get a much better idea of how much shipping a
country has by counting in tons rather than by the number of ships; for
twenty-five ships of one thousand tons each have only half as much
sea-power as one ship of fifty thousand tons.) The British loss was
nine millions, half as much again as was lost by all the rest of the
world put together. Raiders like the cruiser _Emden_, or the armed and
disguised merchant vessel _Moewe_, did a great deal of harm at the
beginning of the war, as we have seen already. Mines did even more
harm, and did it all through. But submarines did most.

Our title "Submarining" means any kind of underwater attack, by mines
as well as by torpedoes, so we must take a glance at the mines before
coming to the submarines.

Most mines are somewhat like big buoys with little horns all over the
top. Each horn ends in a cap which, when hit, sets off the charge.
Mines coupled together by a steel rope are more dangerous than two
separate mines would be, as they are bound to be drawn in against any
ship that strikes any part of the rope. The only safeguard a ship
could carry was a paravane. A paravane is made up of a strong steel
hawser (rope) that serves as a fender, and of two razor-edged blades
that serve to cut the mine-moorings free. It is altogether under water
and is shaped like a V, with the point jutting out on the end of steel
struts ahead of the bows, the two strokes running clear of the sides,
and their ends well winged out astern, where the two sharp blades stand
straight up, one from each end. The lines by which mines are anchored
were thus guided clear of the ship till they reached the blades, where
they were cut. The mines then rose to the surface, where they could be
set off at a safe distance. Dragging a paravane through the water made
the ship go slow. But that was better than being blown up.

Minefields cannot, of cou