as either set on fire or
sunk. In an hour the havoc wrought at Zeebrugge had wiped out the work
of months.

Ross had little time to notice the work of destruction. His particular
business was to observe the fire directed upon a large redoubt to the
north-east of the town. The first shell from the monitor fell short,
blowing an enormous crater in the grass-grown dunes. The second fell
beyond, completely demolishing a house. The third dropped fairly in
the centre of the redoubt, causing a terrific explosion that was not
due solely to the lyddite bursting-charge. The magazine had exploded.

Skywards rushed an enormous cloud of black and yellow smoke. Caught by
the blast of the violently displaced air the sea-plane rocked, then
began dropping like a stone.

For the moment Ross imagined that the end had come. He was no longer
afraid. A sensation of intense curiosity as to what the machine and
its occupants would look like seemed to obsess his mind.

Then, with a jerk that reminded the midshipman of the sudden starting
of a lift, the sea-plane "flattened out" and began to climb out of the
enveloping cloud of smoke.

The Flight-Sub turned his head and grinned broadly. His manner could
not do otherwise than inspire confidence. Although not a pilot, he was
master of the frail machine. Side-slips and nose-dives troubled him
but little, provided he was flying at a safe altitude.

"A jolly good wipe-out!" he exclaimed. "There won't be many Bosches
left within half a mile of that battery, I'm thinking. Now watch when
the next shot lands: that will give you the objective."

A sharp buzzing in the receiver attached to Ross's flying helmet
announced that the monitor was "calling up" her observer. Quickly the
lad seized the pencil, and gave the signal that he was ready to take
down the message.

The Morse signal, when translated into writing, was as follows:--

"Register Position 47."

"Good!" exclaimed the Plight-Sub when Ross had telephoned him the
message. He consulted his map, which was similar to the one at the
observer's disposal "Position 47: that's a railway junction."

In the course of their work of fortifying Zeebrugge, the Huns had
constructed a double-track railway, passing within a few yards of the
Dutch frontier for several miles before heading straight for the new
submarine base. Two miles from Zeebrugge the line joined the existing
railway, the junction being recorded on British airmen's map