ch he was
peeping, the idea never once occurred to him that he was in a position
of considerable danger, and that he would be well advised to climb down;
so that it was not until he saw the flashes of flame leap from the
pieces as they were all fired simultaneously that he realised the full
extent of his temerity.

Then, even as he flung himself backward off the support on which he was
standing, there came a terrific concussion, followed by a rumbling roar
as an avalanche of stone went crashing to the ground below; while the
very building itself, massive as it was, quaked as though the whole
edifice were on the point of crumbling to pieces. Frobisher, dazed and
half-stunned by the tremendous shock, and nearly blinded by the shower
of dust and mortar that came pouring in upon him, found himself lying on
his back on the floor, surrounded by a pile of instruments and machines,
blocks of stone, and other debris, until it seemed nothing short of a
miracle that he had not been crushed to pieces.

As it chanced, however, he had not received so much as a scratch, and
found, as he picked himself up, that nothing worse had befallen him than
the acquisition of sundry fresh bruises. And as he was already a mass
of contusions from head to foot, he felt that one or two more made very
little difference.

He was just about to climb up again to his point of vantage--for he was
intensely interested in learning the outcome of this stubborn little
fight by the sea-shore--when he happened to glance upward in order to
ascertain whether there were any more loose blocks of stone likely to be
dislodged and fall on him. As he did so he caught sight of another ray
of daylight shining into the gloom of his prison. Upon investigation he
saw that the last three shots from the rebel guns must have been so well
aimed as to have struck practically the same spot, for, sure enough,
there was a ragged hole in the wall, slightly above the window and a
little to the left of it, apparently at the junction of the ceiling of
his cell and the floor of the chamber above, just big enough for him to
thrust his head through. Also, what was more to the point, it was
evident that very little effort would be needed to pull down more of the
shattered masonry, and so enlarge the hole sufficiently to enable him to
crawl through.

But, he decided, it would be sheer suicide for him to attempt to escape
at this particular juncture. The mere appearance of his head