r
the sea itself.

From the whirling coils of the tides and races round the coast, he
judged that the sea-bed was as seamed and broken and full of faults as
the visible cliffs ashore.

In bad weather, the men in those submarine galleries and the
outbranching tunnels could hear the crash of the waves above their
heads, and the rolling and grinding of the mighty boulders with which
they disported.

If, by chance, the sea should break through, the peril to life and
property would be great.

He therefore caused to be constructed and fitted inside each tunnel, at
the point where it branched from its main gallery, a stout iron door,
roughly hinged at the top and falling, in case of need, into the flange
of a thick wooden frame. The framework was fitted to the opening on the
seaward side, in a groove cut deep into the rock round each side and
top and bottom. The heavy iron door, when open, lay up against the roof
of the tunnel and was supported by two wooden legs. If the sea should
break through, the first rush of the water would sweep away the
supporting legs, the iron door would fall with a crash into the flange
of the wooden frame, and the greater the pressure the tighter it would
fit.

So the weight of the sea would seal the iron door against the wooden
casement, which would swell and press always tighter against the rock,
and that boring would be closed for ever. And if any man should be
inside the tunnel when the sea broke through, there he must stop,
drowned like a rat in its hole, unless by a miracle he could make his
way along the tunnel before the trap-door fell.

Gard never ceased to enjoin the utmost caution on the men who undertook
these outermost experimental borings.

His strict injunctions were to cease work at the first sign of water in
these undersea tunnels, make for the gallery, close the trap, and await
events.

Believing absolutely in the existence of one or more great central
deposits whence all these thin veins of silver had come, and hoping to
strike them at every blow of his pick, old Tom Hamon was the keenest
explorer and opener of new leads in the mine.

"The silver's there all right," he said, time and again, "it only wants
finding," and he pushed ahead, here and there, wherever he thought the
chances most favourable.

He took his rightful pay along with the rest for the work he did, but it
was not for wages he wrought. Ever just beyond the point of his
energetic pick lay fortune, an