boring had been completed, Barbicane set to work upon the
central mould. His object now was to raise within the center of
the well, and with a coincident axis, a cylinder 900 feet high,
and nine feet in diameter, which should exactly fill up the
space reserved for the bore of the Columbiad. This cylinder was
composed of a mixture of clay and sand, with the addition of a
little hay and straw. The space left between the mould and the
masonry was intended to be filled up by the molten metal, which
would thus form the walls six feet in thickness. This cylinder,
in order to maintain its equilibrium, had to be bound by iron
bands, and firmly fixed at certain intervals by cross-clamps
fastened into the stone lining; after the castings these would
be buried in the block of metal, leaving no external projection.
This operation was completed on the 8th of July, and the run of
the metal was fixed for the following day.
“This _fete_ of the casting will be a grand ceremony,” said J.
T. Maston to his friend Barbicane.
“Undoubtedly,” said Barbicane; “but it will not be a public _fete_”
“What! will you not open the gates of the enclosure to all comers?”
“I must be very careful, Maston. The casting of the Columbiad
is an extremely delicate, not to say a dangerous operation, and
I should prefer its being done privately. At the discharge of
the projectile, a _fete_ if you like– till then, no!”
The president was right. The operation involved unforeseen
dangers, which a great influx of spectators would have hindered
him from averting. It was necessary to preserve complete
freedom of movement. No one was admitted within the enclosure
except a delegation of members of the Gun Club, who had made the
voyage to Tampa Town. Among these was the brisk Bilsby, Tom
Hunter, Colonel Blomsberry, Major Elphinstone, General Morgan,
and the rest of the lot to whom the casting of the Columbiad was
a matter of personal interest. J. T. Maston became their cicerone.
He omitted no point of detail; he conducted them throughout the
magazines, workshops, through the midst of the engines, and
compelled them to visit the whole 1,200 furnaces one after
the other. At the end of the twelve-hundredth visit they were
pretty well knocked up.
The casting was to take place at twelve o’clock precisely.
The previous evening each furnace had been charged with 114,000
pounds weight of metal in bars disposed cross-ways to each other,
so as to allow the hot air to circulate freely between them.
At daybreak the 1,200 chimneys vomited their torrents of flame
into the air, and the ground was agitated with dull tremblings.
As many pounds of metal as there were to cast, so many pounds of
coal were there to burn. Thus there were 68,000 tons of coal
which projected in the face of the sun a thick curtain of smoke.
The heat soon became insupportable within the circle of furnaces,
the rumbling of which resembled the rolling of thunder. The powerful
ventilators added their continuous blasts and saturated with
oxygen the glowing plates. The operation, to be successful,
required to be conducted with great rapidity. On a signal given
by a cannon-shot each furnace was to give vent to the molten
iron and completely to empty itself. These arrangements made,
foremen and workmen waited the preconcerted moment with an
impatience mingled with a certain amount of emotion. Not a soul
remained within the enclosure. Each superintendent took his
post by the aperture of the run.
Barbicane and his colleagues, perched on a neighboring eminence,
assisted at the operation. In front of them was a piece of
artillery ready to give fire on the signal from the engineer.
Some minutes before midday the first driblets of metal began to
flow; the reservoirs filled little by little; and, by the time
that the whole melting was completely accomplished, it was kept
in abeyance for a few minutes in order to facilitate the
separation of foreign substances.
Twelve o’clock struck! A gunshot suddenly pealed forth and shot
its flame into the air. Twelve hundred melting-troughs were
simultaneously opened and twelve hundred fiery serpents crept