If they could sink two battleships in three days, why didn’t the German undersea boats sink a dozen or so more and raise the siege of the Dardanelles? Enver Pasha, the Turkish minister of war, declared that “the presence of the submarines destroyed all hopes of Russia’s ever effectively landing troops on the coast north of Constantinople.” Then why did they permit the landing of British, Australian, New Zealand, and French troops on the Gallipoli Peninsula and the plains of ancient Troy? It was not until August, 1915, that the transport _Royal Edward_ was sunk in the Mediterranean by an Austrian submarine. Perhaps before this war is over some British transport may be torpedoed in the North Sea or the English Channel, but for more than a year and a half since its outbreak, troop-ships and store-ships have been crossing to France as if there were not a hostile “U-boat” in the world. Equally mysterious has been the immunity of the light-draft monitors and obsolescent gunboats off the Flemish coast, where their heavy guns did so much to check the first German drive on Calais, and have harassed the invaders’ right flank ever since. Many of these are mere floating platforms for one or two modern guns, all are slow-steaming, and they are not always in water too shallow for an undersea boat to swim in, yet none have been sunk by a submarine since the loss of the _Hermes_, in the autumn of 1914. Zeebrugge, the Belgian port that has been made the headquarters for German submarines in the North Sea, has been several times bombarded by the British fleet and, according to reports from Amsterdam, half-built submarines on the shore there have been destroyed by shell-fire. Why did the completed undersea boats in the harbor fail to come out and torpedo or drive away the attacking fleet? We have been shown what modern submarines can do; what prevents them from doing much more?