As late as the third year of the war it could not be said that the possibilities of a๋rial offense had been thoroughly developed by any nation. The Germans indeed had done more than any of the belligerents in this direction with their raids on the British coast and on London. But, as already pointed out, these raids as serious attacks on strategic positions were mere failures. Advocates of the increased employment of aircraft in this fashion insist that the military value to Germany of the raids lay not so much in the possibility of doing damage of military importance but rather in the fact that the possibility of repeated and more effective raids compelled Great Britain to keep at home a force of thirty thousand to fifty thousand men constantly on guard, who but for this menace would have been employed on the battlefields of France. In this argument there is a measure of plausibility. Indeed between January, 1915, and June 13, 1917, the Germans made twenty-three disastrous raids upon England, killing more than seven hundred persons and injuring nearly twice as many. The amount of damage to property has never been reported nor is it possible to estimate the extent of injury inflicted upon works of a military character. The extreme secrecy with which Great Britain, in common with the other belligerents, has enveloped operations of this character makes it impossible at this early day to estimate the military value of these exploits. Merely to inflict anguish and death upon a great number of civilians, and those largely women and children, is obviously of no military service. But if such suffering is inflicted in the course of an attack which promises the destruction or even the crippling of works of military character like arsenals, munition plants, or naval stores, it must be accepted as an incident of legitimate warfare. The limited information obtainable in wartime seems to indicate that the German raids had no legitimate objective in view but were undertaken for the mere purpose of frightfulness.
The methods of defence employed in Great Britain, where all attacks must come from the sea, were mainly naval. What might be called the outer, or flying, defences consisted of fast armed fighting seaplanes and dirigibles. Stationed on the coast and ready on the receipt of a wireless warning from scouts, either a๋rial or naval, that an enemy air flotilla was approaching the coast, they could at once fly forth and give it battle. A thorough defence of the British territory demanded that the enemy should be driven back before reaching the land. Once over British territory the projectiles discharged whether by friend or foe did equal harm to the people on the ground below. Accordingly every endeavour was made to meet and beat the raiders before they had passed the barrier of sea. Beside the flying defences there were the floating defences. Anti-aircraft guns were mounted on different types of ships stationed far out from the shore and ever on the watch. But these latter were of comparatively little avail, for flying over the Channel or the North Sea the invaders naturally flew at a great height. They had no targets there to seek, steered by their compasses, and were entirely indifferent to the prospect beneath them. Moreover anti-aircraft guns, hard to train effectively from an immovable mount, were particularly untrustworthy when fired from the deck of a rolling and tossing ship in the turbulent Channel.
Third in the list of defences of the British coast, or of any other coast which may at any time be threatened with an a๋rial raid, are defensive stations equipped not only with anti-aircraft guns and searchlights but with batteries of strange new scientific instruments like the "listening towers," equipped with huge microphones to magnify the sound of the motors of approaching aircraft so that they would be heard long before they could be seen, range finders, and other devices for the purpose of gauging the distance and fixing the direction of an approaching enemy.
Some brief attention may here be given to the various types of anti-aircraft guns. These differ very materially in type and weight in the different belligerent armies and navies. They have but one quality in common, namely that they are most disappointing in the results attained. Mr. F. W. Lancaster, the foremost British authority on aircraft, says on this subject:
"Anti-aircraft firing is very inaccurate, hence numbers of guns are employed to compensate."
[Illustration: Photo by International Film Service.
German Air Raiders over England.
In the foreground three British planes are advancing to the attack.]
