Such “sailing under false colors” to fool the enemy’s cruisers is an old and well-established right of merchantmen of belligerent countries. Its abuse, under present-day conditions, however, might have given the German submarine commanders a plausible excuse for sinking neutral vessels. To avoid this, neutral shipowners began to paint the name, port, and national colors on the broadside of each of their steamers, plain enough to be read from afar through a periscope. Then the time came for the war-zone decree to be put into effect, and the world watched with great interest and no little apprehension to see what the submarine blockaders could do. [Illustration: Copyright, London Sphere & N. Y. Herald. German Submarine Pursuing English Merchantman. (Note stern torpedo-tubes, and funnel for carrying off exhaust from Diesel engine.)] Seven British ships were sunk during the first six days. Then came a lull, followed by the announcement by the British Admiralty that between February 23 to March 3, 3805 transoceanic ships had arrived at British ports, 669 had cleared and none had been lost, while two German submarines had been sunk. During the eleven weeks between the establishing of the blockade and the sinking of the _Lusitania_, forty-two oversea vessels and twenty-eight fishing boats of British registry had been sunk by the submarines, but 16,190 liners and freighters had safely run the blockade. The largest number of vessels sunk by the “U-boats” in any one week was thirty-six, between June 23 and 30; while nineteen British merchantmen, with a total tonnage of 76,000, and three fishing vessels were destroyed either by submarines or mines during the week ending August 25. The total number sunk in the first six months was 485. But with more than fifteen hundred ships coming and going every week, the submarine blockade of the British Isles was obviously a failure. It was a costly failure from the military point of view. The expenditure of torpedoes alone must have been considerable and a modern Whitehead or Schwartzkopf costs from five to eight thousand dollars and takes several months to build. How many of the “U-boats” themselves have fallen prey to the British patroling craft, traps, mines, and drag-nets cannot be computed with any accuracy, but by the first of September, 1915, the number declared to be lost “on the authority of a high official in the British Admiralty” ran anywhere from thirty to fifty. Even if she has been completing a new submarine every week since the war began, Germany cannot afford the loss of so much material, and still, less, of so many trained men. Captain Persius, one of the foremost German writers on naval affairs, pointed this out in a newspaper article that brought a hurricane of angry criticism about his ears. How great has been the wear and tear on the nervous systems of the submarine crews is shown by the following extract from the statement of Captain Hansen of the captured _U-16_.