What had in fact happened was that, under the stimulus of war, both scientific research and achievement had advanced, as regarded the submarine, with unprecedented strides. From a range of scores to a range of hundreds and even thousands of miles, they had become effective. They had begun to attain a speed that put them on superior terms to the vast bulk of mercantile steamers; and they already carried guns that, before the war, it would have been thought impossible to mount, and that were in fact heavier than those carried by the earlier German destroyers. Nor had the measures of defence as yet overtaken those of destruction in the race for stability. The methods that, to a great extent, had been successful in dealing with the smaller submarines had become obsolete; and the devising of others, their practical application, and the safeguarding, in the meantime, of our mercantile marine--more than half a million {203} tons of mercantile shipping were, at this time, being sunk every month--were problems upon whose solution depended not only the victory of the Allied cause, but the actual physical existence of the people upon these islands. Of the means ultimately adopted, of which it may at once be said that none was in itself a complete solution, it would be impossible, in the present volume, to give more than the briefest details. The plotting out of minefields for which 100,000 mines, of an improved type, were ordered by Admiral Jellicoe, and of which the most extensive was designed to stretch from the north of Scotland to the waters of Norway; the construction and employment on a vast scale of speedy patrol vessels of all descriptions; the regular use of aircraft, both for observation and the dropping of depth-charges; and the development of the convoy system with destroyer escorts, as the increase in the production of the latter justified this--it was rather to a combination of all these methods, and the skill and adaptability of the men employing them, that the ascendency over this new weapon was slowly regained. Of one particular means, however, namely the employment of lure ships--armed vessels, variously disguised--no record of our naval activities from the personal standpoint could omit some account; and of the amazing courage and ingenuity with which the _Q_ ships, as they were called, were handled, let the following couple of examples, chosen at random, sufficiently indicate.