o reply.

Behind the U-16 the other German submarines followed closely, two
abreast. Aboard each the men stood to their posts, awaiting the signal
they expected at any minute. All the vessels moved along upon the
surface. The officers, from their places upon the bridge, followed with
their eyes the movements of the U-16, which displayed a small stern
light to guide them on.

In case of danger Lord Hastings had been instructed to give immediate
warning, that the vessels behind might have time to dive.

Perhaps a hundred yards away in the darkness Frank's keen eyes now made
out the forms of many little craft approaching them silently and
swiftly. He immediately called Lord Hastings' attention.

"The motorboats," replied the latter quietly. "Things are working out
just right."

Behind the motorboat flotilla could be seen forms of larger and mightier
ships of war--the torpedo boats which were advancing in the wake of the
mosquito fleet to surround the enemy submarines and capture or sink
them. They came along close to the shore on either side of the river and
the U-16 continued up the river in the exact center.

"When we get by, they'll close in," said Lord Hastings.

But now one of the commanders with the motorboat flotilla could restrain
his impatience no longer, and while still some distance from the enemy
gave the command to fire.

A single big gun boomed in the darkness and a shell screamed over the
U-16 toward the German submarines beyond.

"The fool!" exclaimed Lord Hastings angrily. "Why could he not wait?
There is no reason for concealment longer."

Immediately he gave the signal agreed upon with the German admiral, the
darkening of the tail light--the signal for the others to submerge--and
the U-16 dashed forward faster than before--to reach a place of safety
as quickly as possible and to get out of range of the British ships,
which, a moment later, opened upon the enemy with every available gun.

Directly opposite the U-16 there was a terrible explosion, a blinding
flash, illumining the night like day. A German submarine had launched a
torpedo and it had gone home. The foremost British torpedo boat had been
destroyed.

But the others rushed on.

The Germans had heeded Lord Hastings' signal to submerge and were doing
their best to disappear beneath the water before the British could reach
them, the while firing an occasional torpedo, in the hope that it would
go true, for they were unable to find t