ADE WITH GERMANY.--Neutral countries
adjoining Germany had been making huge profits by selling their food and
other products to Germany, replacing their stores with material imported
from over seas. As part of the preparation for a long war, the Allies
blocked the renewal of neutral stocks of goods. The neutral countries
complained vigorously, but they soon cut down their trade with Germany
since they were no longer able to replenish their stock of food, rubber,
metals, and other supplies.

SUBMARINE WARFARE.--In 1914, when the war broke out, Germany is said
to have had but four seaworthy submarines. It is difficult to believe
that she had so few, but it is certain that she did not have so many as
either England, France, or Russia. German naval authorities were not
convinced of the value of the submarine in war.

However, about a month after the war began, a German submarine torpedoed
a British cruiser, and, within a few minutes, two others that had gone
to assist the first. Germany, now realizing the value of the new weapon,
began the construction of a numerous fleet of underwater boats, or
U-boats. But against war ships, properly defended by guns and other
means, they proved of little avail after all. Toward the end of the
year, Admiral von Tirpitz, head of the German navy, hinted at an
extension of the use of submarines to attack merchant ships.

Soon numbers of the submarines made their way to the waters surrounding
the British Isles, where they torpedoed merchant vessels taking food and
supplies to Great Britain and France. The vessels sunk were chiefly
British, though some were neutral.

PROTECTION AGAINST SUBMARINES.--Large war ships were protected from
submarines by keeping them in a mine-protected area until there was need
for them at sea. At sea they were protected largely by the patrol and
scouting operations carried on by lighter and faster vessels. To reduce
the danger to merchant vessels from submarines, harbors and sea lanes
were protected by mines and by great nets made of heavy wire cables. The
seas in the immediate vicinity of Great Britain were patrolled by
thousands of small, swift vessels constantly in search of U-boats.

ATTEMPTED BLOCKADE OF GREAT BRITAIN.--In February, 1915, Germany
declared a blockade of the British Isles. Under an actual blockade she
would have the right to prevent neutral vessels from trading with Great
Britain. But inasmuch as it was not possible to take seized neutral
s