Page:Aircraft in Warfare (1916).djvu/252

§ 126 to its known restrictions as a form of heat engine, it may be regarded as safe for all time. The position of Belfast is such that, even if we assume the whole Netherlands. Belgium and the French littoral to be in the hands of an enemy, the distance to be flown is approximately 400 miles, during almost the whole of which distance enemy aircraft will have to run the gauntlet of our air defence, both aeroplane and counter aircraft artillery.

§ 127. Comparison with Navy. It is true that the Aeronautical Arm is not alone in requiring manufacturing facilities during the period of hostilities, and in being liable to the dislocation of these facilities by its own kind. The same is true, but in far less degree, of the Navy; in the latter these facilities (in the form of our Naval building yards and dockyards) are quite essential to the proper upkeep of the Fleet, although the amount of new construction (in comparison with aircraft) is relatively small. It is nevertheless regarded by the Naval authorities as essential that our dockyards, etc., shall be so placed as to be capable of effective defence against naval raids, and any situation which cannot be made to comply with this condition has sooner or later to be abandoned, or at least new bases have to be created to take over its more important functions. The position of the Aeronautical Arm, however, is unique in the relatively great importance of the daily output of new machines, and in the relative ease with which this may be interfered with by enemy enterprise if due precautions are not taken. Thus the present recommendation may be regarded as the extension of a principle, admitted in the selection for the site of a ship-building yard or dockyard, to the choice of a headquarters for aeronautical construction.

It is extremely doubtful whether we shall witness