t and the batteries on the
Isle of Wight shore had been previously switched off. Since the Needle
Channel was closed to all mercantile shipping, the _Capella_ could, and
did, without risk, extinguish her navigation lights. Only the
phosphorescent spray from her sharp cutwater marked her position.

Suddenly she ported helm, just in time to avoid a collision with a long
dark shape that proved to be an unterseeboot in the act of diving. Her
commander had detected the pulsations of the _Capella_ motors, but he
was too late.

Round spun the patrol vessel. From her quarter, a long length of
something that resembled an exaggerated string of sausages was paid
out. At the rate that the _Capella_ was circling, it was impossible
for the U-boat to escape from her toils. Dive to a safe depth she
could not, since the maximum depth was but 5 3/4 fathoms.

The last of the "sausages", to which was attached stout flexible wire,
disappeared beneath the water. Then a jerk upon the wire announced the
gratifying fact that the fugitive submarine had fouled the string of
sausages, which was in reality a number of gun-cotton charges, primed
and connected to a powerful battery by means of an insulated wire.

Sub-lieutenant Fox, who was standing by the firing-key, needed no
orders. His fingers pressed the ebonite disc. A hundred yards astern
of the _Capella_ a column of water was flying high in the air, followed
by a tremendous roar. For one minute the vessel rocked violently in
the agitated waters, then, circling, she made for the spot under which
the explosion had occurred. With a splash a mark-buoy was dropped
overboard to indicate the position of the shattered U-boat. By this
time the torpedo-boats had arrived on the scene.

"A deuce of a commotion on shore, Barry," exclaimed the skipper.

"I should be surprised if there were not, sir," replied the Sub. "The
racket was enough to smash every window within a couple of miles of the
beach. They're signalling, sir."

"German submarine's boat rowing off. Intercept her," was the signal
spelt out by the long and short flashes.

"More work," remarked Barry. "It's like looking for a needle in a
bottle of hay. Shall I order the searchlight to be run, sir?"

"Very good," replied Captain Syllenger. "But before you do so you
might signal to Hurst, and request that all available search-light be
brought to bear in this direction."

Soon the hitherto pitch-dark sea was flooded in