The Huns had concentrated the glare of numerous searchlights on the hub
of the squadron's activities, so that the speeding planes could be seen
darting hither and thither like bats during an August evening, darting
around some arc-light in the street.

The flash of the distant guns aboard the planes looked like faint
fire-flies in action. No longer was the earth wrapped in darkness, for
flares dropped by the bombers kept continually on fire. The bridge stood
plainly out, and a keen eye, even without the aid of glasses, could
distinguish the rush of terrorized German troopers trying to get clear of
the danger zone before a well directed bomb struck home.

Jack, leaning from his seat, took all this in. He was keyed to the
top-notch by what he saw and heard. Tame indeed did most other incidents
of the past appear when compared with this most stupendous event.

"Wow!" burst from his lips, as a sudden brilliant flash below told that
the first huge bomb had struck; but with all that racket going on around
of course no ordinary human voice could have been heard.

He could see that it had not been a successful attempt, for the bomb
struck the ground at some little distance away from the terminus of the
structure spanning the river. However, it did considerable damage where
it fell, and created no end of alarm among those who were near by.

As yet the Air Service Boys had not been engaged with any of the hostile
planes, though most of the other Yankee pilots seemed to be having their
hands full in meeting and repelling fierce attacks.

Both kept in readiness for work should their turn come, Tom manipulating