Determined, however, upon a spectacular demonstration of its possibilities, Germany first published danger notices in American newspapers, and then, on May 7, 1915, sank the unarmed Cunard liner _Lusitania_ off the Irish coast, with a loss of 1198 lives, including 102 Americans. In spite of divided American sentiment and a strong desire for peace, this act came little short of bringing the United States into the war. Having already declared its intention to hold Germany to "strict accountability," the United States Government now stated that a second offense would be regarded as "deliberately unfriendly," and after a lengthy interchange of notes secured the pledge that "liners will not be sunk without warning and without safety of the lives of non-combatants, provided that the liners do not try to escape or offer resistance." Violations of this pledge, further controversies, and increased friction with neutrals marked the next year or more, during which, however, sinkings did not greatly exceed the level of about 150,000 tons a month already attained. During this period Allied countermeasures were chiefly of a defensive character, including patrol of coastal areas, diversion of traffic from customary routes, and arming of merchantmen. This last measure, making surface approach and preliminary warning a highly dangerous procedure for the submarine, led Germany to the announcement that, after March 1, 1916, all armed merchant vessels would be torpedoed without warning. But how were U-boat commanders to distinguish between enemy and neutral vessels? Between vessels with or without guns? The difficulty brings out clearly the fact that while the submarines made good pirates, they were hampered in warfare on legitimate lines. Germany redoubled U-boat activities to lend strength to her peace proposals at the close of 1916, and when these failed she decided to disregard altogether the cobwebs of legalism that had hitherto hindered her submarine war. On February 1, 1917, she declared unrestricted warfare in an immense barred zone within limits extending from the Dutch coast through the middle of the North Sea to the Faroe Islands and thence west and south to Cape Finisterre, and including also the entire Mediterranean east of Spain. An American ship was to be allowed to enter and leave Falmauth once a week, and there was a crooked lane leading to Greece. [Illustration: GERMAN BARRED ZONES British mined area and North Sea mine barrage.]