nder it safe, but, with truly Hunnish
ingenuity, the metal out of which an essential part of this appliance
was made was quite unable to bear the strain imposed by its work, and,
to make doubly sure, another part was half filed through. The result was
that, instead of rendering the mine safe when torn from its moorings by
rough seas, the essential parts broke and left the mine fully _alive_.

Any discovery such as this--_only made at the great risk of salving a
live mine_--could be easily explained away by German diplomacy as faulty
workmanship in a particular weapon, reliance being placed on the fact
that not many mines could be salved in this way without heavy loss of
life; but numbers were recovered in spite of the dangers and
extraordinary difficulties of such operations, and the guilt was for
ever established in the minds of those who sail the seas.

Little need be said here regarding the method of laying mines from
surface ships like the _Wolfe_ and _Moewe_. The weapons were arranged to
run along the decks on railway lines and roll off the stern, or through
a large port-hole, into the sea as the vessel steamed along.

With submarine mine-layers or U-C boats the method was, however, much
more complicated and needs full description. Each vessel was fitted with
large expulsion tubes in the stern and carried some eighteen to twenty
mines. These weapons, although similar in their internal mechanism to
the ordinary mine, were specially designed for expulsion from submerged
tubes or chambers.

The mines were stored in the stern compartment of the submarine, between
guide-rails fitted with rollers. They were in two rows and moved easily
on the well-greased wheels. The loading was accomplished through
water-tight hatchways in the deck above. In order to expel these mines
from the interior of the submarine when travelling under the surface
each weapon had to be moved into a short expulsion tube or chamber, the
inner cap of which was closed when a mine was inside, and the outer or
sea-cap opened. A supply of compressed air was then admitted into the
back of the tube and the mine forced out into the open sea, in the same
way as a torpedo is now expelled from a submerged tube.

Before another mine could be launched the sea-cap had to be closed, the
water blown from the tube, the inner cap opened and a second mine placed
ready in the chamber. This, however, did not end the difficulty of
laying mines from submarines. The inc