Thus the battle cruiser had justified itself, and its justification is one of the striking lessons of the war. We may believe that the lesson will be emphasized if the time ever comes when this type finds the opportunity to display its adaptability for work in certain other fields for which it was originally designed--in scouting operations, for example, and in flanking movements in connection with a fleet engagement. It does not appear that aeroplanes were used for scouting in any of the operations in the open sea--either as preliminary to the battle off Coronel and the Falklands, or in the search for raiders like the _Emden_ and the _Karlsruhe_. They have been used, however, in the waters about the British Islands, and with such marked success as to leave no doubt that they would have been of great value in search operations on a larger scale. They were used also for directing the fire of ships on the fortifications at the Dardanelles, and the results indicate that they have an important field of usefulness for directing the fire of one ship or fleet against another. It is to be expected that from this time forward, vessels fitted for carrying and launching both air and water planes will accompany fleets, and it is impossible to think of a scout to be designed after the lessons of this war, which will not carry several of them. As the scouts are the eyes of the fleet, so the aeroplanes will be the eyes of the scouts, extending the scouting range by several hundred miles and making secrecy of operations at sea almost as impossible as they have already made it on land. Allusion has already been made to the use of aeroplanes--flying not more than a few hundred feet above the water--for locating submarines; and it is not difficult to understand how effective a waterplane would be for destroying a periscope, or even a submarine itself--this last, perhaps, by dropping a bomb.