During the eight months which were employed in the work of excavation the preparatory works of the casting had been carried on simultaneously with extreme rapidity. A stranger arriving at Stones Hill would have been surprised at the spectacle offered to his view.

At 600 yards from the well, and circularly arranged around it as a central point, rose 1，200 reverberating ovens, each six feet in diameter, and separated from each other by an interval of demi-toise. The circumference occupied by these 1，200 ovens presented a length of two miles.Being all constructed on the same plan, each with its high quadrangular chimney, they produced a most singular effect.

It will be remembered that on their third meeting the committee had decided to use cast iron for the Columbiad, and in particular the white description. This metal, in fact, is the most tenacious, the most ductile, and the most malleable, and consequently suitable for all moulding operations；and when smelted with pit coal, is of superior quality for all engineering works requiring great resisting power, such as cannon, steam boilers, hydraulic presses, and the like.

Cast iron, however, if subjected to only one single fusion, is rarely sufficiently homogeneous；and it requires a second fusion completely to refine it by dispossessing it of its last earthly deposits. So long before being forwarded to Tampa Town, the iron ore, molten in the great furnaces of Coldspring, and brought into contact with coal and silicium heated to a high temperature, was carburized and transformed into cast iron.After this first operation, the metal was sent on to Stones Hill.They had, however, to deal with 136，000，000 pounds of iron, a quantity far too costly to send by railway.The cost of transport would have been double that of material.It appeared preferable to freight vessels at New York, and to load them with the iron in bars.This, however, required not less than sixty-eight vessels of 1，000 tons, a veritable fleet, which, quitting New York on the 3rd of May, on the 10th of the same month ascended the Bay of Espiritu Santo, and discharged their cargoes, without dues, in the port at Tampa Town.Thence the iron was transported by rail to Stones Hill, and about the middle of January this enormous mass of metal was delivered at its destination.

It will easily be understood that 1，200 furnaces were not too many to melt simultaneously these 60，000 tons of iron. Each of these furnaces contained nearly 140，000 pounds weight of metal.They were all built after the model of those which served for the casting of the Rodman gun；they were trapezoidal in shape, with a high elliptical arch.These furnaces, constructed of fireproof brick, were especially adapted for burning pit coal, with a flat bottom upon which the iron bars were laid.This bottom, inclined at an angle of 25 degrees, allowed the metal to flow into the receiving troughs；and the 1，200 converging trenches carried the molten metal down to the central well.

The day following that on which the works of the masonry and 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 fête 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 fête.”

“What！Will you not open the gates of the enclosure to all comers?”

“I must be very careful, J. T.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 fête 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 toward the central well, unrolling their incandescent curves.There, down they plunged with a terrific noise into a depth of 900 feet.It was an exciting and a magnificent spectacle.The ground trembled, while these molten waves, launching into the sky their wreaths of smoke, evaporated the moisture of the mould and hurled it upward through the vent-holes of the stone lining in the form of dense vapor-clouds.These artificial clouds unrolled their thick spirals to a height of 500 toises into the air.A savage, wandering somewhere beyond the limits of the horizon, might have believed that some new crater was forming in the bosom of Florida, although there was neither any eruption, nor typhoon, nor storm, nor struggle of the elements, nor any of those terrible phenomena which nature is capable of producing.No, it was man alone who had produced these reddish vapors, these gigantic flames worthy of a volcano itself, these tremendous vibrations resembling the shock of an earthquake, these reverberations rivaling those of hurricanes and storms；and it was his hand which precipitated into an abyss, dug by himself, a whole Niagara of molten metal！

在挖井工程进行的那八个月时间里，铸炮的准备工作也以极快的速度同时在进行。如果一个外地来的人来到乱石岗，他会对呈现在眼前的景象感到十分惊讶。

在离井口六百码的地方，围绕中心点垒起了一千二百个反射炉，每个炉子直径六英尺，彼此间隔半托瓦兹。这一千二百个反射炉连接起来形成一条线的话，可长达两英里。它们全都是一个模式，都有一个四角形的高大烟囱，景象十分壮观。

大家记得，委员会召开第三次会议时，便决心使用铸铁铸造哥伦比亚大炮，还特别指定用灰铸铁来造。这种金属的确更加有韧性，有延展性，更加易于锻压，易于镗孔，适应各种模具铸模；而且，经泥煤处理之后，质地上乘，适合制作各种高强度的机件，比如大炮、蒸汽压路机、水压机等。

不过，铸铁如果只经过一次熔化的话，很难保持质地均衡，必须通过第二次熔化，除去它最后的那些泥土杂质之后，才能变得纯净无瑕。因此，铁矿石在运往坦帕城之前，必须先在科尔德斯普林的高炉里加工处理，在高温之下与炭和硅接触，进行碳化，并转化成铸铁。经过第一道工序之后，铸铁被运到乱石岗。但是，一亿三千六百万磅的铸铁，如果通过铁路运输的话，运费十分昂贵，比材料的费用多一倍。看来，在纽约租一些船，装上铸铁锭更划算一些；但这也起码得租六十八条载重一千吨的大船，那可真算得上一支船队了。五月三日，这支大船队驶离纽约，于当月十日在圣埃斯皮里图湾靠岸，毫发未损地停泊在坦帕城港口。船上的铸铁被卸到码头，装到通往乱石岗的火车上。一月中旬[43]，这堆积如山的金属终于运抵目的地。

不难想象，要同时熔炼这六万吨铸铁，一千二百个熔炉也不算太多。每个熔炉可容纳将近十四万磅的金属。它们都是按照当年为铸造罗德曼大炮所需之铸铁的模式建造的，呈梯形，非常低矮。加热装置和烟囱都在熔炉两端，因而熔炉各个部位都能均匀受热。熔炉全都用耐火砖制成，只装置着一个用以燃烧泥煤的铁架，以及一张摆放铸铁锭的“炉床”。这张“炉床”呈二十五度角倾斜，以便熔化了的金属得以流入承流器里；然后，一千两百条槽沟便将金属液引向中央基坑之中。

井壁和坑洞工程完工后的第二天，巴比凯恩便着手制造内模：在坑洞的中心，以它的轴心为基准，立起一个九百英尺高、直径九英尺的圆柱，它毫厘不差地填满留给哥伦比亚大炮炮膛的空间。该圆柱由黏土和沙土混合制成，其中掺了一些干草和稻草。铸模和井壁之间留下的空隙得灌满金属液，这些金属液将成为六英尺厚的炮筒壁。为了让这个大圆柱保持平衡，必须用一些铁框架将它固定住，并每隔一段用横梁插入井壁，加以支撑。炮壁铸成之后，这些横梁便与已凝固的金属契合在一起，外表看不出任何痕迹了。

七月八日，铸模工程宣告结束，第二天将开始铸炮。

“铸炮的开工仪式肯定很精彩。”J.T.马斯顿对他的朋友巴比凯恩说道。

“当然，”巴比凯恩回答道，“不过，那不会是一个公众的节日！”

“怎么！您不把围墙的门打开让人们前来参观吗？”

“小心为佳，马斯顿。铸造哥伦比亚大炮尽管不能说是一种危险的试验，但也是一种大意不得的试验哪。我宁愿关起门来铸造它。到发射炮弹的时候，如果愿意的话，倒是可以庆贺一番，但在这之前，庆祝是绝对不可以的。”

巴比凯恩主席说的是有道理的。这种试验可能会出现一些预料不到的危险，而观者如云的话，一旦遇到危险，场面必然一片混乱，无法控制。必须保证试验不受任何干扰。除了前来坦帕城的大炮俱乐部会员们的一个代表团之外，任何人都不得进入围墙内。该代表团成员包括潇洒倜傥的比尔斯比、汤姆·亨特、布洛姆斯贝瑞上校、埃尔菲斯通少校、摩根将军等人，对他们来说，铸造哥伦比亚大炮已经变成他们个人的事情了。J.T.马斯顿充当起他们的向导来，向他们讲解每一个细节，带他们四处参观，去弹药库，去车间，去机器中间，还硬要让他们一个一个地参观那一千二百个熔炉。等参观到第一千二百个熔炉时，他们已经实在是累得受不了了。

铸炮在正午时开始。前一天，每座炉子都装满了十一万四千磅的铁锭，交叉叠放着，以便热气得以在铁锭中间自由流动。从早晨起，那一千二百座熔炉便开始向空中喷吐出大量的火焰，大地都在颤动着。装填了多少磅的金属，就得燃烧多少磅的煤。因此，六万八千吨煤同时在阳光的照射下喷出浓烟，形成一块厚厚的黑幕布。很快，熔炉圈内的温度直线上升，让人无法忍受，再加上轰隆声响成一片，如雷声滚滚。大功率的鼓风机也夹杂其中，呼呼地连续地往炉内吹风，氧气充足，炉火很旺。要想成功，就得快速完成这项工作。号炮一响，每个熔炉就必须立即把金属液引出，让炉子排空。一切安排就绪之后，工头们和工匠们都怀着一种激动而焦急的心情，等待着那决定性时刻的到来。熔炉圈内的人全都被疏散开了，而每个熔炉炉长都守候在金属液槽边，坚守着自己的岗位。

巴比凯恩及其同事们站在近旁的一个高处，观看出炉。他们前面放着一门大炮，等工程师一发信号便发炮。正午前几分钟，有小滴小滴的金属液开始流出，承流器渐渐积满。铸铁完全熔化之后，还得在承流器里待上片刻，以便让金属液里的杂质沉淀下去。

十二点整。突然一声炮响，一道黄褐色的光亮在空中一闪。一千二百个金属液槽同时打开，只见一千二百条火蛇向中央基坑爬行着。到了基坑边，只听见一阵可怕的巨响，金属液便哗哗地向九百英尺深的深渊滚滚地倾泻着。场面十分壮观，非常激动人心。金属液一边向空中喷吐着滚滚浓烟，一边让铸模里的湿气蒸腾，变成一股股的蒸汽，从井壁的通气孔中冒出来。这时候，大地都在颤动。这些假云假雾呈螺旋状向天穹升腾，直达五百托瓦兹的高空。如果远方有个野人，看到这番景象的话，还以为佛罗里达州深处可能有一处火山在喷发。不过，那可不是火山爆发，不是龙卷风，不是暴风雨，不是大自然在发威。不是！全都不是！是人的威力，是人在制造这些红褐色的蒸汽，是人在制造这些可与火山媲美的巨大火焰，是人在制造这些宛如地震一般的、可怕的、震耳欲聋的声响，是人在制造这些与狂风骤雨匹敌的轰鸣，是人的双手在把像尼亚加拉大瀑布似的金属液倾入自己挖出的深渊中！