Besides scouting and "spotting" and bombing, the aerial hunters of the submarine developed great value in escorting convoys. A few dirigibles, located on the flanks of a convoy, protected them almost as effectively as the destroyers themselves; and even a single airship not infrequently brought a group of merchantmen and troopships safely into port. Sometimes the airships operated in this way as auxiliaries to destroyers, while sometimes they operated alone. In applying this mechanism of protection to merchant convoys, we were simply adopting the method which Great Britain had been using for three years in the narrow passages of the English Channel. Much has been said of the skill with which the British navy transported about 20,000,000 souls back and forth between England and France in four years; and in this great movement seaplanes, dirigibles, and other forms of aircraft played an important part. In the same way this scheme of protection was found valuable with the coastal convoys, particularly with the convoys which sailed from one French port to another, and from British ports to places in Ireland, Holland, or Scandinavia. I have described the dangers in which these ships were involved owing to the fact that the groups were obliged to break up after entering the Channel and the Irish Sea, and thus to proceed singly to their destinations. Aircraft improved this situation to a considerable extent, for they could often go to sea, pick up the ships, and bring them safely home. The circumstance that our seaplanes, perched high in the air, could see the submarine long before they had reached torpedoing distance, and could, if necessary, signal to a destroyer for assistance, made them exceedingly valuable for this kind of work.