800,000 tons of shipping were destroyed. Unless this loss
could be greatly reduced the Allies for want of food and materials would
soon have to give up fighting.

But methods were quickly devised to combat the new danger. The patrols
were increased, ships voyaged under convoy of fast destroyers constantly
hovering about on the watch for submarines, and other protective
measures were taken, so that the submarine menace was soon much reduced.
By September, 1918, the sinkings were only about 150,000 tons a month,
while the production of ships, especially in the United States, has
increased to several times this amount.

Apparently Germany had waited until she had built a large number of
submarines, thinking that by the use of a great fleet of them in a
ruthless warfare on shipping she could force a peace within a few
months. In this expectation she was disappointed. The principal result
of the withdrawal of her pledge to this country was the entrance of the
United States into the war on the side of the Allies. Captain Persius,
an expert German naval critic, admitted in November, 1917, that the
German admiralty was grossly mistaken in its calculations and that
Germany had no reason for believing in the decisive influence of the
submarine war.

THE UNITED STATES DRIFTS TOWARD WAR.--The breaking off of diplomatic
relations is not a declaration of war. Nevertheless the events
immediately succeeding the withdrawal of Count von Bernstorff made a
declaration of war increasingly probable. The most important of these
were the publication of the Zimmerman note, the fact that several
American merchant ships were actually sunk by German submarines, and the
discovery that members of the German embassy and other German diplomatic
representatives had been concerned in plotting on United States soil
against the Allies, thus endangering our peaceful relations with them.
Not only so, but there was evidence that plots had been laid to destroy
American lives and property in this country and to stir up internal
disorders, such as strikes and riots.

THE ZIMMERMAN NOTE.--On the last day of February, the Secretary of
State published a note that had come into his possession which was
addressed by Dr. Zimmerman, the German foreign minister, to the German
minister in Mexico. The note stated that Germany would soon begin a
ruthless submarine warfare and proposed, if the United States should
declare war on Germany, that Mexico should enter into