It was the 22nd of November; the departure was to take place in ten days. One operation alone remained to be accomplished to bring all to a happy termination; an operation delicate and perilous, requiring infinite precautions, and against the success of which Captain Nicholl had laid his third bet. It was, in fact, nothing less than the loading of the Columbiad, and the introduction into it of 400,000 pounds of gun-cotton. Nicholl had thought, not perhaps without reason, that the handling of such formidable quantities of pyroxyle would, in all probability, involve a grave catastrophe; and at any rate, that this immense mass of eminently inflammable matter would inevitably ignite when submitted to the pressure of the projectile. There were indeed dangers accruing as before from the carelessness of the Americans, but Barbicane had set his heart on success, and took all possible precautions. In the first place, he was very careful as to the transportation of the gun-cotton to Stones Hill. He had it conveyed in small quantities, carefully packed in sealed cases. These were brought by rail from Tampa Town to the camp, and from thence were taken to the Columbiad by barefooted workmen, who deposited them in their places by means of cranes placed at the orifice of the cannon. No steam-engine was permitted to work, and every fire was extinguished within two miles of the works. Even in November they feared to work by day, lest the sun's rays acting on the gun-cotton might lead to unhappy results. This led to their working at night, by light produced in a vacuum by means of Rühmkorff's apparatus, which threw an artificial brightness into the depths of the Columbiad. There the cartridges were arranged with the utmost regularity, connected by a metallic thread, destined to communicate to them all simultaneously the electric spark, by which means this mass of gun-cotton was eventually to be ignited.