Why not utilise this propensity? Mark the case “watches,” “jewellery,” or “bullion,” cause it to be surrounded with a certain amount of mystery and precaution enough to engender suspicion; and leave the rest to the chisel and drill of the would-be thief.
But this, though clever, was too uncertain. Another idea which occurred to him was to have a wooden case only, but a strong one, and to confine in a small hole prepared for the purpose one of the boring insects, which in a certain time would be sure to eat its way through and leave an aperture.
This, too, was more ingenious than practicable. He was delayed for a time. Accident solved the difficulty. Passing through the streets, he was stopped by a crowd which had collected around a quack doctor.
“See,” cried the vendor of patent vegetable pills, “here is the horrid stuff the allopathists, the doctors and physicians sell to you at high prices. Here is a common drug used by them in this phial. I will pour some of the liquid upon the hard stone pavement—just see how it acts upon the granite, and then guess how your wretched stomachs must be abused.”
He poured it on the stone—the crowd pressed forward, and saw it eat a hole. “Aquafortis,” thought Theodore, and the idea was his—aquafortis was the agent he wanted.
He passed on, and left the crowd thoroughly convinced of the tricks played by the medical faculty, and purchasing largely of the vegetable pills. Theodore had found a substance which would eat through his iron and wood cases, and leave an aperture—a substance, too, whose action was equal, and could be regulated to a sufficiently accurate extent.
Upon reflection, however, and after making several experiments, he did not employ ordinary aquafortis, but another acid equally powerful, and which was still more regular in its action. He tried the experiment time after time, till at last he obtained the proper strength, and fixed the requisite amount of acid to eat through a given thickness of iron and wood in a certain time. He repeated the experiment till he was absolutely certain of the result.
The plan had now grown delightfully clear and well-defined—the infernal machine became of the simplest construction. All that had to be done was to place the acid in the case confined in a small and very thin copper vessel (lined with an enamel to resist it), which was to be screwed to one side of the case, then pump the gas in, hermetically seal it, heave the whole thing on board the steamer, and leave it to work its way. Delightfully simple!
He called Marese to look over his drawings, and to witness his experiments with the acid. Marese was enchanted; his confidence in Theodore’s scientific resources was confirmed. There was, however, one question he asked—Was the gas so strong and so poisonous that the small quantity confined in a case three feet square would destroy a whole ship’s company? Would not the gas escape, rise up, and dissipate itself through the portholes, up the hatchways, and be further weakened by the breezes that blew and caused draught in various places between decks? These ocean steamers were very roomy.
Theodore was delighted to have an opportunity of explaining the properties and nature of the vapour to his friend. The peculiarity of this gas was that, although an invisible fluid, it was extremely heavy—it was heavier far than atmospheric air. He easily proved that a gas might be heavier than air by a well-known experiment with a vapour (not the one to be used in this case) which he poured out of a glass phial over a candle. The invisible gas descended and extinguished the candle; There was not the slightest chance of the poison-vapour escaping quickly through ports or up hatchways. It would, as it were, cling to the vessel. The pressure inside the case would cause it to issue rapidly from the aperture eaten out by the acid. It would then diffuse itself laterally, and gradually penetrate into every crevice and corner of the ship. The effect would be that one by one every person on board would inhale it, and in an instant, let the quantity breathed be never so small, down he would drop, or grow rigid as he sat—unconscious was the word Theodore used as an euphemism for death. He did not mention another effect it would have, lest the horror of it should cause even Marese to falter.
Theodore traced out the probable course of events on board the fated vessel. First, the persons working or living in the cabins and places nearest the case would feel the effect and succumb. Then there would be alarm and excitement—others would rush to the spot, and they would immediately fall, just as the birds and beast did who entered those fatal caves abroad. One man on board, perhaps, might detect the cause—the surgeon, or any doctor who chanced to be a passenger—and might cry out to man the boats and escape; but who, in the hurry and excitement, would heed him?—he would not have time to escape himself, much less to explain the danger to others. It was doubtful whether even so much as a signal of distress would be hoisted. The crew, the officers, the passengers would be so completely puzzled, so utterly at their wit’s end, that no course would suggest itself to them before it was too late.
In this respect the gas had an immense advantage over any apparatus which would set the ship on fire. Let the fire be never so rapid, one boat at least might get away, and on that boat
