hat,
in consequence of this order, a Von Tirpitz council presented this
answer: Attacking submarines were equipped with explosive mines
containing 300 to 400 pounds of nitroglycerin or guncotton. To the top
of this mine was fastened a fake periscope. This devilish device was
attached to the submarine by a light cable, and towed along the surface
of the water 1000 feet or more behind the submarine. The result that
would follow any attempt on the part of a commander to run down one of
these decoys is readily imagined.

DESCRIPTION OF A PERISCOPE.

The periscope is distinctly a submarine device which is worthy of brief
description. It is, in effect, a long tube, with an elbow joint at the
top and a similar one at the bottom. At the elbow joints at both ends
are arranged reflectors. The reflector in the upper end catches the
object which comes within the range of vision, and reflects the image
down the tube to the mirror at the lower elbow, where the pilot sees it.
The principle of the periscope is the same as that of the "busybody,"
familiar to householders, and which is placed on the sill of an upper
window, so that a person inside the house may see who is at the front
door.

The Germans have recently devised a new form of periscope, designed to
make the device invisible to the lookout of approaching boats. This
device consists of two mirrors, put together like a "Y" lying on its
side, the wide part in front. These skim through the waves and converge
the image upon the low periscope's lens, which shoots the light down the
tube to the receiving apparatus below. When looked at from a distance
the mirrors reflect the surface of the sea, so that a lookout sees
nothing but the waves as they are reflected in the mirror.

The Germans use the bottom of the sea as regular "land" for their supply
bases, and when the submarines go to the surface it is precisely like an
aeroplane mounting the air. The submarine fleet boasts also of "mother
boats." They lie on the bottom of the ocean, in designated places, and
rise at night to hand out their supplies. Crews are changed and tired
men go back to the bottom to rest up, while fresher comrades take their
places.

So, too, the submarine, with its ability to rest on the bottom of the
sea, has become an efficient boat for mine laying. The mine layers work
from the undersea boats without fear of disturbance, the divers walking
out from the submarines to the floor of the sea without bei