ches deep, which it
soon carried away. To this soil succeeded two feet of fine sand, which
was carefully taken out, as it was to be used for the casting.

After this sand white clay appeared, similar to English chalk, and which
was four feet thick.

Then the pickaxes rang upon the hard layer, a species of rock formed by
very dry petrified shells. At that point the hole was six and a half
feet deep, and the masonry was begun.

At the bottom of that excavation they made an oak wheel, a sort of
circle strongly bolted and of enormous strength; in its centre a hole
was pierced the size of the exterior diameter of the Columbiad. It was
upon this wheel that the foundations of the masonry were placed, the
hydraulic cement of which joined the stones solidly together. After the
workmen had bricked up the space from the circumference to the centre,
they found themselves inclosed in a well twenty-one feet wide.

When this work was ended the miners began again with spade and pickaxe,
and set upon the rock under the wheel itself, taking care to support it
on extremely strong tressels; every time the hole was two feet deeper
they took away the tressels; the wheel gradually sank, taking with it
its circle of masonry, at the upper layer of which the masons worked
incessantly, taking care to make vent-holes for the escape of gas during
the operation of casting.

This kind of work required great skill and constant attention on the
part of the workmen; more than one digging under the wheel was
dangerous, and some were even mortally wounded by the splinters of
stone; but their energy did not slacken for a moment by day nor night;
by day, when the sun's rays sent the thermometer up to 99 deg. on the
calcined planes; by night, under the white waves of electric light, the
noise of the pickaxe on the rock, the blasting and the machines,
together with the wreaths of smoke scattered through the air, traced a
circle of terror round Stony Hill, which the herds of buffaloes and the
detachments of Seminoles never dared to pass.

In the meantime the work regularly advanced; steam-cranes speeded the
carrying away of the rubbish; of unexpected obstacles there were none;
all the difficulties had been foreseen and guarded against.

When the first month had gone by the well had attained the depth
assigned for the time--i.e., 112 feet. In December this depth was
doubled, and tripled in January. During February the workmen had to
contend against a sh