During the European War airships were used most effectively by the navies in scouting work, locating mine fields, discovering sub marines and communicating information to their own vessels either by signal or by radio. Air ships are remarkable scouts and under ordinary conditions, in a few hours, can explore an im mense horizon and inform surface warships by radio as to conditions for miles around. A fleet covered by a sufficiently large flotilla of such scouts can navigate with a practical certainty of avoiding surprise from a hostile or superior force. As to effectiveness the airship has a great advantage over the aeroplane in long sustained flights, especially over sea. The aero plane must land immediately in case of a mis hap such as a stalled engine, a fractured pro peller blade, etc., while an airship, on the con trary, can remain afloat and make repairs. Every well-balanced fleet should include a flo tilla of airships. In the European War when it became necessary to build up a system of pro tection against submarines, the warring nations pressed into service thousands of small vessels, destroyers, trawlers and submarine chasers; and as fast as they could obtain them they put into service seaplanes and dirigibles to co-operate with the ships in locating and capturing and destroying hostile submarines and in convoying ships, protecting them from submarine attacks. The usual evidence of the submarine's presence is the wake of the periscope. This wake can not easily be seen from ships, but can always be clearly seen from airplanes. For one thing the aviator is not troubled by the reflection of the rays of light which interfere with the vision of the person on a ship. The aviator, flying at a height of from 1,000 to 5,000 feet, has a range of vision of many miles and the whitish wake of the periscope is clearly visible against the dark surface of the waters even in cases where the sea is fairly rough and white caps are showing. Whatever the future develop
ment may be, the basis of any air service is its two-seated observation squadrons who do the work of observation, both visual by day and by night and photographic infantry liaison and artillery adjustment. A squadron of airplanes of this type must be provided for every divi sional corps staff and army staff. The plans announced call for coast defense squadrons and observation and bombing squadrons. Inas much as the coast defense squadrons under army control are not expected to operate far beyond the range of the coast defense guns, all work further at sea is the duty of the navy. It is impossible to develop a comprehensive and efficient system of naval aeroplane tactics un less there are material and personnel sufficient to permit working with the fleet in large groups. These and many other problems must be worked out in peace time and the personnel carefully drilled, especially in the co-ordinating features of their work. Because of the high speeds and the great number of, units dealt with in naval aeronautics, there is no branch or department of service work where thorough co-ordination is more vital to success. The art of flying is a comparatively insignificant part of a naval aviator's attainments. When in command of an aeroplane he must not only be an expert flyer but he must also be well versed in the whole subject of naval aeroplane tactics as well as being an expert seaman and navigator. See AERONAUTICS, HISTORY OF; AEROPLANE; MILI TARY AERONAUTICS.