this one was rapidly dissolving; but, from all that we
needed to learn from it, the record was as complete as a bronze relief.

"That there was to be another chapter to the story became evident before
we had doubled back half the length of that part of the wake we had
sprinkled with 'cans.' At about the point where two-thirds of that sheaf
of depth-charges had been expended a clearly defined wake of oil and
bubbles turned sharply off to the left. The presence of that little
trail cleared up several important points right then and there without
following it any farther, though I will hardly need to tell you that we
didn't drop anchor to hold a court of inquiry over it. The vital thing
it told us was that--strange as it seemed--our under-water bombardment
had not sent the U-boat to the bottom, nor even injured it sufficiently
to compel it to come to the surface. But that it was injured, and
probably fairly badly, was proved by the wake of oil and bubbles. Don't
ever let any one delude you with that yarn about the way Fritz sends up
oil and bubbles to baffle pursuit. There may be circumstances under
which he could work that particular brand of foxiness with profit, but
if there is one place where you could be sure he would _not_ try
anything of that kind on, it is when a destroyer has got his nose on his
trail, with her eye and ears a-cock for just that kind of little
first-aid to 'can-dropping.' For a submarine voluntarily to release air
or oil when a destroyer is ramping round overhead would be just about
like a burglar scattering a trail of confetti to baffle the pursuit of
the police. Fritz is as full of ways that are dark and of tricks that
are vain as Ah Sin, but--with the hounds at his heels--nothing so
foolish as that oil and bubble stunt of popular fiction.

"The first few of the 'cans' had evidently burst near enough to this
Fritz to buckle his shell and release the oil and air, but his sharp
right-angled turn to the left had taken him quite clear of the last of
the charges, which had only been thrown away. Wounded and winged as he
appeared to be, the next thing in order was to polish him off. Slowing
down slightly, the captain steadied the _Sherill_ on the wake.

"As we passed the point where this was rising, the rate at which it was
extended gave the approximate speed of the U-boat, and the fact that
this was not above three knots seemed only another indication that all
was not well with him. Holding on past t