In a matter of seconds he was poised above the great, sprawling city. An air-raid was in progress and he paused for a moment to view with interest London as it must appear to a Nazi airman. The broad, curving serpent of the Thames was clearly visible, and that alone was sufficient for him to identify various districts, but away from the river it was clear that the Nazi raiders could make only the vaguest guess as to when they were over their targets except on a night when the moon was particularly bright. The black-out was undoubtedly efficient, since although pin-points of light could be seen as far as the eye could reach in every direction they were no more than glimmers, so that it was impossible to detect any pattern in their dispositions which might have given away the situation of broad thoroughfares, railway-stations or big buildings. The gunfire was sporadic, but in certain cases the flashes were so bright that for a second they lit the whole area in which the more powerful anti-aircraft batteries were situated.
