in the morning
under the cover of darkness. Keeping in close touch, the submarines
spread out over the sea like a huge fan. Behind them at a distance of
five miles moved the supporting column of dreadnoughts, battle cruisers,
destroyers, scouts and mine sweepers---units in the great fleet bent
upon the task of smashing the German stronghold.

The _Monitor_ led off in the battle array. Copies of the chart of
Zeebrugge, the original that had been found on the converted U-boat
at the time of her capture, had been given to every submarine skipper
in the fleet. Each had his orders for this all-important night.

"Here we go!" murmured McClure to his aides as he signaled his fleet
of submarines forward into the fray.

Picking his way according to the German chart, he set a zigzag course.
At length the officers of the _Monitor_ knew they were closing in,
and so far successfully. The submarines were running submerged
with only the tips of their periscopes showing.

All at once there appeared in the sky directly ahead of the _Monitor_
a line of red lights. A German birdman, circling above on patrol duty,
had observed the wake of the periscopes and had touched off a night
flare.

Like a giant pyrotechnic display the red globules floated in the air.

No sooner had the light appeared than there came the boom of a big gun
on shore and a huge shell screeched seaward over the _Monitor_.
Instantly the coast defense guns of the Germans crashed into action.
And now, from the rear of the _Monitor_ and her consorts, came the
answering crash of the great guns on the mighty ships of the Allies.

The furious battle was on!

German aviators, having sighted the American submarines, were bending
all their energies on wiping out the "invisible mosquitoes." Guided
only by the telltale wake of the periscopes, they were dropping huge
depth bombs at random. One of them splashed into the sea directly
astern of the _Monitor_.

"We will have to act quickly now," urged McClure as he rang for full
speed.

So far, so good; not a mine had been encountered. The _Monitor_ was
worming her way unmolested into the heart of the enemy stronghold!

Convinced now that he had passed the guardian line of nets and mines,
McClure decided to dive and run for the inner recesses of the enemy
harbor. Now down, out of sight, out of hearing of the big guns, the
_Monitor_ relentlessly pursued her course, flouting the danger that
lurked on every hand.

A