1915, the success of German submarines
had been so marked that the insurance rates on merchantmen went
up. Lloyd's underwriters announced that the rate on transatlantic
passage had gone up nearly one per cent. And on the same day it
was announced that the British Government would thereafter regulate
steamship traffic in the Irish Sea. Certain areas of the Irish
Sea were closed to all kinds of traffic; lines of passage were
defined and had to be followed by all merchantmen, and vessels
of all descriptions were ordered to keep away from certain parts
of the coast from sunset to sunrise.

The comparatively small size of the submarines made it possible
for the German admiralty to load them on to trains in sections
and transport them where needed, and in this manner some were sent
from the German ports on the North Sea to Zeebrugge, there assembled
and launched. Others were sent to the Adriatic, arriving at Pola
on the 25th of February, 1915. These were intended for use in the
Mediterranean as well as in the Adriatic Sea.

Neutral ships, in order to escape attack by German submarines had
to resort to unusual methods of self-identification. The use of flags
belonging to neutral countries by the merchantmen of belligerent
powers made the usual identification by colors almost impossible,
the German admiralty claiming that the commanders of submarines were
unable to wait long enough, after stopping a vessel, to ascertain
whether she had a right to fly one flag or another. Consequently
the ships belonging to Dutch and American lines had their names
painted with large lettering along their sides. At night, streamers
of electric lights were hung over the sides to illuminate these
letterings; and on the decks of many of the neutral ships their
names and nationalities were painted in large letters so that they
might be identified by aircraft. Owing to such precautions the
Dutch steamship _Prinzes Juliana_ escaped being sunk by a torpedo
on the 3d of March, 1915. A submarine ran a parallel course to
that followed by the Dutch ship, but after examining the lettering
on her sides the commander of the German craft saw that she was
not legitimate game and turned off.

Not always did the German submarines themselves succeed in escaping
unharmed in their raiding of allied merchantmen. Rewards were offered
in Great Britain for the sinking of German submersibles by the
commanders of British merchantmen. Instructions were issued in
the Br