Those who watched the arrival of this impressive flight of
wild birds in regular formation, with the bomb-droppers occupying the inner line and the fighting machines which protected them outside, will always have an image of it in their minds. But it is necessary to say at once that the appearance of low altitude and slowness of flight was probably quite deceptive. The German machines were exceptionally large, and the'sky was very clear. Thus the raiders seemed to be much lower than they were, and experts estimated their altitude at not less than 13,000 feet. As for the speed, that also was probably deceptive, for at a very great height the angle changes slowly, and on the whole it is better to trust probability than visual impressions, and to suppose that the raiders were going " all out " when they passed over London.
