SUBMARINE WARFARE.--During the year 1916 Germans continued with increasing success their policy of sinking merchant vessels, neutral and enemy. Out of a total of nearly 4,000,000 tons of shipping destroyed from the beginning of the war to January 1, 1917, more than half was lost during 1916. Occasional loss of life also caused much doubt on the part of our government as to whether Germany was keeping her pledge to safeguard the lives of noncombatants on torpedoed liners. When a passenger steamer, the "Sussex," plying between England and France, was torpedoed without warning (March 24, 1916), eighty of the passengers were killed or injured, two of the latter being Americans. Germany at first said that one of her submarines had torpedoed a vessel in the vicinity, but not the "Sussex." The finding of fragments of a German torpedo on the "Sussex" after it was brought into port conclusively proved that the Germans were responsible, and that Germany had broken her promise. President Wilson addressed a note to the German government, stating that he would sever diplomatic relations with it unless Germany should both declare and effect an abandonment of her unlawful methods of submarine warfare. Thereupon the German government gave a written pledge that merchant ships "shall not be sunk without warning and without saving human lives, unless these ships attempt to escape or offer resistance." This pledge was given on the condition that the United States should demand that Great Britain observe certain (disputed) rules of international law; but our government refused to agree that Germany's respect for our neutral rights should be made to depend on the conduct of other nations. President Wilson thus made clear his intention to sever diplomatic relations if Germany's pledge should be withdrawn or violated. CONSCRIPTION IN GREAT BRITAIN.--The British government had kept up its army by volunteering. The need of an army of five million could not depend on this plan. A conscription bill therefore was passed making all males between certain ages liable for military service. Ireland was excepted from the provisions of this act. SINN FEIN REBELLION.--Some of the more radical among the Irish Home Rule party had formed an organization known as the Sinn Fein (shin fān), an Irish phrase which means "for ourselves." Their aim was to make Ireland an independent nation. The leaders of this group got into correspondence with persons in Germany and were promised military assistance if they would rebel against England. The rebellion broke out April 24, 1916, without the promised help from Germany. For several days the rebels held some of the principal buildings in Dublin. After much bloodshed the rebellion was put down, and Sir Roger Casement, one of those who had been in communication with Germany, was executed for treason.