Italy entered the war with vigor although at a great disadvantage.  When the northern Italian lands were freed from Austrian rule in 1866, Austria kept the highlands and mountain passes, from which she could easily descend upon the Italian lowlands.  Now that war was begun, the Italians were compelled to force their way up the heights and against the fire from well-protected Austrian forts.  Here upon the dizzy peaks of the Alps, or the icy surfaces of glaciers, or the rocky mountain sides, warfare has been more spectacular and has called for more daring and recklessness than anywhere else.  Slides of rock and avalanches of ice sometimes have been the ammunition of armies.  During the year the Italians made some progress and by December occupied positions well within the Austrian frontier; but no decisive battle had been fought or important city or fortress occupied.

ALLIED CONTROL OF THE SEA.—­Throughout 1915—­as in the preceding and the following years—­the Allies maintained their control of the ocean.  As a result of a proclamation declaring the North Sea a military area, and the more strict enforcement of the proclamation against sending contraband articles to Germany, the blockade against the Central Powers was more tightly drawn.

This seriously affected the commerce of the United States, not only with Germany but with neutral countries, such as Holland or Sweden, that could easily transship to Germany the supplies received.  Neutral vessels were stopped and taken into Allied ports, there to be detained sometimes for long periods until a decision was reached as to the legality of their traffic.  Moreover, the expense of this detention was laid upon the owners of the vessel and cargo.  These acts brought forth a series of protests by our government against the policy of the Allies.  The correspondence continued with varying results until the United States entered the war.

FORCED DECREASE OF NEUTRAL TRADE 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.