Chapter 14 - Page 2

in 255 days; that is to say, in round numbers,
2,000 cubic feet per day. That which would present no difficulty
to a thousand navvies working in open country will be of course
more troublesome in a comparatively confined space. However, the
thing must be done, and I reckon for its accomplishment upon your
courage as much as upon your skill."

At eight o'clock the next morning the first stroke of the
pickaxe was struck upon the soil of Florida; and from that
moment that prince of tools was never inactive for one moment
in the hands of the excavators. The gangs relieved each other
every three hours.

On the 4th of November fifty workmen commenced digging, in the
very center of the enclosed space on the summit of Stones Hill,
a circular hole sixty feet in diameter. The pickaxe first
struck upon a kind of black earth, six inches in thickness,
which was speedily disposed of. To this earth succeeded two
feet of fine sand, which was carefully laid aside as being
valuable for serving the casting of the inner mould. After the
sand appeared some compact white clay, resembling the chalk of
Great Britain, which extended down to a depth of four feet.
Then the iron of the picks struck upon the hard bed of the soil;
a kind of rock formed of petrified shells, very dry, very solid,
and which the picks could with difficulty penetrate. At this
point the excavation exhibited a depth of six and a half feet
and the work of the masonry was begun.

At the bottom of the excavation they constructed a wheel of oak,
a kind of circle strongly bolted together, and of immense strength.
The center of this wooden disc was hollowed out to a diameter
equal to the exterior diameter of the Columbiad. Upon this wheel
rested the first layers of the masonry, the stones of which were
bound together by hydraulic cement, with irresistible tenacity.
The workmen, after laying the stones from the circumference to
the center, were thus enclosed within a kind of well twenty-one
feet in diameter. When this work was accomplished, the miners
resumed their picks and cut away the rock from underneath the wheel
itself, taking care to support it as they advanced upon blocks of
great thickness. At every two feet which the hole gained in depth
they successively withdrew the blocks. The wheel then sank little
by little, and with it the massive ring of masonry, on the upper
bed of which the masons labored incessantly, always reserving some
vent holes to permit the escape of gas during the operation of
the casting.

This kind of work required on the part of the workmen extreme
nicety and minute attention. More than one, in digging
underneath the wheel, was dangerously injured by the splinters
of stone. But their ardor never