_Pilcomayo_ stood in to the support of their consort, and in a very few
minutes Jim beheld the somewhat rare spectacle of a close fleet action
in which the sides were well matched, for the two Peruvian monitors were
of about equal strength to the three Chilian warships. The thunder of
the cannon now became deafening, and Callao bay was positively flecked
with white by the hundreds of ricochetting shells and solid shot; while
even at the distance of four miles the boys could see, through their
telescopes, the ships' hulls reel and quiver under the frightful impact
of the shot and shell.

But the combat did not last very long, for the merciful darkness came
down about an hour after the monitors had been towed out, and put an end
to the action. The signal for recall was hoisted aboard the _Blanco
Encalada_, the firing gradually ceased, the _Huascar, Angamos_, and
_Pilcomayo_ got their anchors, and shortly after nightfall the whole
Chilian fleet was once more anchored safely under the lee of San Lorenzo
island.

These tactics and the bombardment of Callao continued day after day, and
the port seemed to be as far from surrendering as it was when they
began; but the Chilians found, after the first few days, that it was
necessary to lay down permanent moorings under San Lorenzo Island and
buoy them, so that the fleet could leave its berth every night at dusk,
and return when morning dawned. This was because of the fact that the
Peruvians had constructed several fast torpedo-boats which prowled round
the fleet after dark and attempted to torpedo the vessels composing it;
and also to avoid the peril of the floating mines which the enemy put
into the water at the mouth of the harbour and allowed to drift down
upon the Chilian vessels with the tide.

The flagship had, in particular, been made the objective of several of
these torpedo attacks; and it was this fact which put into the head of
the admiral a scheme which he had now been turning over in his mind for
some days past.

On the 8th of May a meeting of officers was convened in Admiral Riveros'
cabin on board the flagship; and Jim was one of the officers present.
It was about seven o'clock in the evening, and darkness had already
closed in, the fleet then steaming, in double column of line abreast, on
and off, about two miles to seaward of their anchorage. As soon as all
the Chilian officers had come aboard Riveros took his seat at the head
of the cabin table, and stra