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
ships to German ports, the submarines would sink them, often without
providing for the safety of the passengers and crews. The ultimate
object of this course of action was so to reduce the world's shipping as
to make it impossible for Great Britain to be supplied with the food or
other materials that would enable her to carry on the war. This method
of warfare, however, was contrary to the well established rules of
international law. Against it the United States and other neutrals made
vigorous protests.

THE LUSITANIA.--The most notable loss by submarine attack was that of
the "Lusitania," sunk without warning off the coast of Ireland on May 7,
1915. Nearly twelve hundred lives were lost, including many women and
children. One hundred and fourteen of those lost were Americans. An
advertisement had been inserted in the papers warning passengers not to
travel on Allied ships, but no one believed that Germany would go so far