found to be fine gold, eighteen carat pure. Such a thing as flinching
when the test came was not to be considered; they would carry through
their appointed tasks or fall while in the endeavor, paying the price the
airman has ever had dangled before his eyes.

Jack was using his night-glass, and he now broke out with a cry.

"We must be getting close to the bridge, Tom! I can see flickering
lights darting about, and I believe they must be planes rushing up
into the air!"

"Like as not they've been warned of our coming by the row we're making,"
replied the pilot, in a shout. "Then again those Huns along the line
would send word back, for they must know what we're aiming at. It's all
the same to us. We came out after action, and we'd be terribly
disappointed if we didn't get a lot of it."

Then came signals from the leading plane. Closer formation was the rule
from that time forward, since the bombers must be amply protected in
order to allow their gunners an opportunity to get to work with those
frightful explosives and hurl them at the place where the bridge was
supposed to lie.

Both boys began to feel their pulses thrill with eagerness, as well as
excitement. Looking down, Jack could detect moving lights, the source of
which he could only speculate upon. Then came a flash which must mark the
discharge of the first anti-aircraft gun. The enemy was showing exceeding
nervousness, for as yet the leading American plane could not be anywhere
within range.

With the burst of shrapnel there came a realization that the gunners
below were only trying to get their range. The whole pack would break
loose in another minute or less; but Jack had reason to believe their
altitude was such as to render the fusillade harmless.

Then down below he saw a sudden brilliant flash. That must mark the
falling of a flaming bomb, dropped from one of the big planes in order to
get a lead on their location. Jack believed he had even glimpsed the
bridge itself in that brief interval. How the prospect thrilled him!

Tom, on his part, had little opportunity to observe anything that was
taking place earthward. His duty lay closer at hand, for he knew that a
swarm of fighting Gothas had started up to engage the attacking squadron,
and realized that one or more of these hostile aircraft might suddenly
appear close at hand, bent on bringing about their destruction.

Besides, constant vigilance was the price of safety in other particulars.
Wit