. After this a framework, or caisson, of stout
timber and boards, was built round the mouth of the shaft, and rendered
watertight with pitch and oakum. It rose to a height of about twelve
feet above the surface of the sea, and was strengthened and supported by
stout bars, or buttresses of timber. A platform was placed on the top,
and a windlass, at which four men could work, was fixed thereon. This
erection was connected with the shore by a stage or "wherry" erected on
piles. The water was cleared out; the men went "underground," and, with
the sea rolling over their heads, and lashing wildly round the turret
which was their only safeguard from terrible and instant destruction,
they hewed daily from the submarine rock a considerable portion of tin.

These first workers, however, had committed an error in carrying on
their operations too near the surface, so that water permeated freely
through the rock, and the risk of the pressure above being too great,
for it rendered the introduction of immense supporting timbers
necessary. The water, too, forced its way through the shaft during the
winter months, so that the regular working of the mine could not be
carried on except in summer; nevertheless, this short interval was
sufficient to enable the projector to raise so much ore that his mine
got the reputation of being a profitable adventure, and it was wrought
successfully for many years.

About the end of the century the depth of the pump-shaft was about four
fathoms, and the roof had been cut away to the thinness of three feet in
some places. Twelve men were employed for two hours at the windlass in
hauling the water, while six others were "teaming" from the bottom into
the pump. When sufficient water had been cleared away the men laboured
at the rock for six hours--in all, eight hours at a time. The prolific
nature of the mine may be gathered from the fact that in the space of
six months ten men, working about one tenth of that time--less than
three weeks--broke about 600 pounds worth of ore. During one summer
3,000 pounds worth of tin was raised!

A steam-engine was ultimately attached to the works, and the mine was
sunk to a depth of sixteen fathoms, but the expense of working it at
length became so great that it was abandoned--not, however, before ore
to the amount of 70,000 pounds had been raised from under the sea!

At the time of our tale another effort had been made to work the Wherry
Mine, and great ex