urnaces
contained about 1,400,000 lbs. of metal; they had been built on the
model of those used for the casting of the Rodman gun; they were
trapezoidal in form, with a high elliptical arch. The warming apparatus
and the chimney were placed at the two extremities of the furnace, so
that it was equally heated throughout. These furnaces, built of
fireproof brick, were filled with coal-grates and a "sole" for the bars
of iron; this sole, inclosed at an angle of 25 deg., allowed the metal to
flow into the receiving-troughs; from thence 1,200 converging trenches
carried it down to the central well.

The day following that upon which the works of masonry and casting were
terminated, Barbicane set to work upon the interior mould; his object
now was to raise in the centre of the well, with a coincident axis, a
cylinder 900 feet high and nine in diameter, to exactly fill up the
space reserved for the bore of the Columbiad. This cylinder was made of
a mixture of clay and sand, with the addition of hay and straw. The
space left between the mould and the masonry was to be filled with the
molten metal, which would thus make the sides of the cannon six feet
thick.

This cylinder, in order to have its equilibrium maintained, had to be
consolidated with iron bands and fixed at intervals by means of
cross-clamps fastened into the stone lining; after the casting these
clamps would be lost in the block of metal, which would not be the worse
for them.

This operation was completed on the 8th of July, and the casting was
fixed for the 10th.

"The casting will be a fine ceremony," said J.T. Maston to his friend
Barbicane.

"Undoubtedly," answered Barbicane, "but it will not be a public one!"

"What! you will not open the doors of the inclosure to all comers?"

"Certainly not; the casting of the Columbiad is a delicate, not to say a
dangerous, operation, and I prefer that it should be done with closed
doors. When the projectile is discharged you may have a public ceremony
if you like, but till then, no!"

The president was right; the operation might be attended with unforeseen
danger, which a large concourse of spectators would prevent being
averted. It was necessary to preserve complete freedom of movement. No
one was admitted into the inclosure except a delegation of members of
the Gun Club who made the voyage to Tampa Town. Among them was the brisk
Bilsby, Tom Hunter, Colonel Blomsberry, Major Elphinstone, General
Morgan, and _t