Theodore, looking up, saw a change upon Marese’s countenance, and immediately knew that something had occurred to him. The heir was pale as death; his own conception, so ghastly and treacherous, filled him with a nameless horror at the same moment that he never hesitated in his purpose. After a while he took up a pen and added to his already written premises the conclusion—his idea in a few brief sentences—and handed it to Theodore. He left it to Theodore to select the gas, and to arrange the mechanical details. He had sown the seed, the other must patiently tend it. And the other did patiently tend it; and this is what it grew to. The name of the gas which Theodore at last, after much thought, fixed upon shall not be here disclosed; for although it is well-known to chemists, and any one who can read could easily find it, there is no knowing what imitations might not spring up if they were aware of the means being so ready at hand. Though suicide is such a simple and obvious expedient in difficulties, yet there are scores who do not commit it because they never think of it. If some kind friend suggested the pistol or the knife they would at once employ it. Gas had one property which rendered it peculiarly fitted for the purpose in view. Being elastic, it could be compressed to a great extent, and thus an immense volume might be contained in a small compass. Therefore the case or receptacle to hold the vapour poison need not be of large dimensions; and this was a matter of some importance. The gas chosen was not in any way explosive; on the contrary, it had the property of extinguishing any light which was placed in it—there was thus no danger of any accidental circumstance causing an explosion at an awkward moment. It was absolutely safe—the operator ran no risk, provided always that he did not inhale the vapour. Theodore sketched out a case about three feet square, which was to be formed of an outer box of deal, and an inner skin of thin iron. Into this case, which would be tolerably strong, he proposed to pump a vast volume of gas, taking care that the pressure should not exceed the power of the box to withstand. The aperture through which it had been pumped was then to be hermetically sealed with molten lead. The greatest difficulty was to provide for the escape of the devilish vapour at the proper moment; and this caused the projectors much reflection. Clockwork was objectionable; it was liable to injury from jars and shakes. Cases of this character, which looked strong and substantial, and would be placed in the hold, would be certain to receive the roughest of usage. At one time he conceived the idea of relying upon the cupidity of the seamen. It was suspected that many of the accidents which had taken place at sea, and caused the destruction of hundreds by fire, had arisen through dishonest seamen or _employés_ on board going at night with a candle into the compartment where valuable goods were stowed, and dropping sparks.