From the Earth to the Moon (14 page)

This made it possible to save a great deal of time, for they were now able to use the new system of digging that has been adopted for wells, in which the masonry is made at the same time as the hole. Thanks to this simple procedure, it is no longer necessary to shore up the earth with braces: the masonry contains it with unshakable strength, and moves itself down by its own weight.

This operation was not to begin until the digging had reached the solid part of the ground.

On November 4, fifty workers dug a circular hole with a diameter of sixty feet at the center of the stockaded enclosure, that is, at the top of Stone Hill.

First they encountered a six-inch layer of black vegetable mold which they went through easily. Then came two feet of fine sand which was carefully taken out, for it was to be used in making the inner mold.

After this sand came four feet of rather compact white clay which resembled the marl in England.

Then the picks struck sparks from a kind of hard, dry, very solid rock, composed of petrified seashells, which they were to struggle against until the end of the digging. At this point the hole was six and a half feet deep, and the masonry work was begun.

At the bottom of this excavation they built an oak disk, firmly bolted and enormously strong, with a hole in its center that had the same diameter as the outer diameter of the cannon. It was on this disk that they built the first courses of masonry, whose stones were held together with inflexible tenacity by hydraulic cement. When they had made stonework from the outer edge to the inner circle, the workers were enclosed in a round pit twenty-one feet across.

Next they took up their picks and mattocks again and began digging under the disk, carefully supporting it with extremely strong blocks. Each time the hole had become two feet deeper, they successively took out the blocks; the disk would then gradually sink, taking with it the massive ring of stonework on top of which the masons were constantly working, not forgetting to make vent holes through which the gas could escape during the casting operation.

This kind of work required great skill and unremitting attention. More than one worker was seriously or even fatally injured by falling stones while digging under the disk. But their zeal never flagged for one minute, day or night. During the day, by the light of a sun that raised the temperature of that scorched plain to ninety-nine degrees a few months later, and at night, beneath the white glow of the electric lights, the noise of the picks striking rock, the explosion of blasting charges, the clanking of machinery,
and swirls of smoke in the air traced around Stone Hill a circle of terror that herds of buffalo and groups of Seminoles did not dare to cross.

Meanwhile the work advanced regularly. Steam cranes speeded the removal of earth. There was little concern for unexpected obstacles. Only foreseen difficulties were encountered, and they were skillfully overcome.

By the end of the first month the pit had reached its scheduled depth of 112 feet. In December this depth was doubled, and in January it was tripled. In February the workers had to combat underground springs that welled up from beneath the surface. Powerful pumps and compressed-air equipment had to be used to draw them off in order to stop up their openings with concrete, as one stops up a leak in a ship. Finally those undesirable streams were mastered. But because of the looseness of the earth, the disk sank on one side and part of the stonework collapsed. Imagine the awesome weight of that stone ring 450 feet high! This accident cost the lives of several workers.

It took three weeks to shore up the stonework, build a support beneath it, and restore the disk to its original position. But thanks to the skill of the engineers and the power of the machines employed, the endangered construction recovered its balance and the excavation continued.

The work was not interrupted by any other incidents. On June 10, twenty days before the date set by Barbicane, the pit, completely sheathed in masonry, reached its final depth of nine hundred feet. At the bottom the stonework rested on a massive thirty-foot cube, while its top was level with the surface of the ground.

Barbicane and the other members of the Gun Club
warmly congratulated Murchison. His herculean task had been carried out with extraordinary rapidity.

During those eight months, Barbicane had not left Stone Hill for one moment. As he had kept close watch on the digging operations, he had been constantly concerned with the health and welfare of his workers, and he was fortunate enough to avoid those epidemics that are common to aggregations of men, and are so disastrous in regions exposed to tropical influences.

Several workers, it is true, paid with their lives for the rashness that is inherent in such dangerous work; but those deplorable accidents are impossible to avoid, and Americans are not inclined to worry about such details. They care more about mankind in general than about the individual in particular. Barbicane professed contrary principles, however, and applied them at every opportunity. Because of his care, his intelligence, his useful intervention in dangerous cases, and his deep, humane wisdom, the accident rate did not go beyond that of European countries noted for their abundant precautions, including France, where there is an average of one accident for every 200,000 francs’ worth of work.

D
URING THE
eight months that were spent on the excavation, the preparatory work for the casting had been done simultaneously and with great speed. A stranger arriving at Stone Hill would have been amazed by what he saw.

Arranged in a circle around the pit with a radius of 600 yards were 1,200 reverberatory furnaces six feet wide and three feet apart. The circumference of this circle of furnaces was over two miles. They were all built to the same design, with a high rectangular chimney, and they produced a singular effect. J. T. Maston felt that it was a magnificent architectural arrangement. It reminded him of the monuments of Washington. For him, there was nothing more beautiful anywhere in the world, not even in Greece, where, he freely admitted, he had never been.

It will be remembered that in its third meeting the committee had decided to use cast iron, specifically the kind known as “gray,” to make the cannon. This metal is tougher, more ductile, easier to bore, and suitable for all casting operations. Melted with coal, it is of superior quality for things that require great strength, such as cannons, steam engine cylinders, hydraulic presses, etc.

But it is seldom homogenous enough when it has been
melted only once. It takes a second melting to purify and refine it by ridding it of all its earthy residues.

Therefore, before being sent to Tampa, the iron ore, melted in the blast furnaces at Cold Spring and placed in contact with heated carbon and silicon, was carburized and transformed into cast iron.
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After this operation, the metal was sent to Stone Hill. But 136,000,000 pounds of iron would have been too expensive to send by rail: the transportation charges would have doubled the cost of the iron. It seemed preferable to charter ships in New York and load them with the iron in bars. It took no less than sixty-eight ships with a capacity of a thousand tons each, a veritable fleet. On May 3 they left New York harbor, headed out to sea, moved southward along the coast to the Straits of Florida, rounded the tip of the peninsula and steamed into Tampa Bay on May 10. They all moored in the port of Tampa without incident.

There the metal was unloaded from the ships and placed in the cars of the Stone Hill railroad. By the middle of January all of the enormous mass had reached its destination.

It will easily be seen that the 1,200 furnaces were not more than was needed to melt that 70,000-ton mass of metal all at once. Each furnace could contain about 114,000 pounds of metal. They had been made on the same pattern as those that had been used in casting the Rodman cannon: they had a trapezoidal shape and were very low. The heating apparatus and the chimney were at opposite ends of the furnace, so that it was equally heated over its entire length. These furnaces, made of firebrick, were composed only of a grate for burning the coal and a
hearth on which the bars of iron were laid. This hearth, inclined at an angle of twenty-five degrees, enabled the molten metal to flow into basins, from which 1,200 converging gutters would take it to the central pit.

The day after the pit had been completed, Barbicane gave orders to begin work on the inner mold. A cylinder nine hundred feet high, with a diameter of nine feet, had to be placed inside the pit, so that it would exactly fill the space reserved for the bore of the cannon. This cylinder was composed of a mixture of clayey earth and sand to which hay and straw had been added. The space left between the mold and the stonework was to be filled by the molten metal, which would thus form walls six feet thick.

To hold the cylinder upright, it had to be stiffened with iron reinforcements and steadied by crosspieces sealed into the stonework. After the casting these crosspieces would remain inside the metal and would have no harmful effect on it.

This operation was completed on July 8 and the casting was scheduled for the next day.

“Our festival of casting is going to be a beautiful ceremony!” J. T. Maston said to his friend Barbicane.

“No doubt,” replied Barbicane, “but it won’t be a public ceremony.”

“What! You’re not going to open the enclosure to anyone who wants to come in?”

“Of course not. Casting the cannon will be a delicate operation, to say nothing of its danger, and I prefer to have it done behind closed doors. When the projectile is fired you can have a festival if you want, but not till then.”

Barbicane was right: the operation might present unexpected dangers, and a large crowd of onlookers might make it impossible to take effective countermeasures. Those involved in the operation would have to keep their
freedom of movement. No one, therefore, was allowed inside the enclosure, except for a group of Gun Club members who had made the trip to Tampa. The group included the dashing Bilsby, Tom Hunter, Colonel Bloomsberry, Major Elphiston, General Morgan, and others. For them, the casting of the cannon was a personal matter. J. T. Maston was appointed to be their guide. He spared them no detail; he took them everywhere—to the powder magazines, the workshops, the machines—and he made them inspect the 1,200 furnaces one after another. By the time they had made their 1,200th inspection their interest had dulled a little.

The casting was to take place at noon. The day before, each furnace had been loaded with 114,000 pounds of metal in bars, arranged in crosshatch stacks so that the hot air could circulate freely among them. The 1,200 chimneys had been spewing their torrents of flame into the air since morning, while the ground was being shaken by dull tremors. For each pound of metal to be melted, a pound of coal had to be burned, so 70,000 tons of coal sent up a thick curtain of black smoke before the sun.

The heat soon became unbearable inside the circle of furnaces, whose roaring was like the rumble of thunder. Powerful blowers added their noise as they saturated the glowing furnaces with oxygen.

To succeed, this operation would have to be carried out rapidly. At the signal given by the firing of a cannon, each furnace was to release its molten metal and empty itself entirely.

When all the preparations had been made, the workers and supervisors waited for the signal with impatient excitement. There was no one in the enclosure now, and each casting foreman was at his post beside the tapholes.

Barbicane and his colleagues watched the operation
from a nearby knoll. Before them was a cannon ready to be fired at a sign from Murchison.

A few minutes before noon, the first drops of metal began to flow. The basins gradually filled, and when the metal was entirely liquid it was kept at rest for a time, in order to facilitate the separation of foreign substances.

At exactly noon the cannon fired, throwing its tawny lightning into the air. Twelve hundred tapholes opened at once, and 1,200 snakes of fire crawled toward the central pit, straightening their incandescent coils. There, with a fearful uproar, they plunged to a depth of nine hundred feet. It was a moving and magnificent spectacle. The ground quivered while those cascades of metal, sending whirlwinds of smoke toward the sky, volatilized the moisture in the mold and shot it through the vent holes in the stonework in the form of dense vapor. These artificial clouds spiraled up to an altitude of 3,000 feet. An Indian wondering beyond the horizon might have believed that a new volcano was being formed in Florida, but this was not an eruption, a tornado, a storm, a struggle of the elements, or any of the other terrible phenomena that nature is capable of producing. No, it was man alone who had created those reddish vapors, those gigantic flames worthy of a volcano, those loud tremors that brought an earthquake to mind, that roar which could rival any hurricane, and it was his hand that had precipitated, into an abyss that he himself had dug, a whole Niagara of molten metal.