Issuing forth into the spacious yard of the gas works, a final demonstration was about to be given to the visitors on their way out. A circular pool, of eighteen feet in circumference, was filled with tar and naphtha. This thick liquid mixture was ignited, and in a few seconds the whole surface sent up a prodigious blaze of great brilliancy. A boy of about eleven years of age (apparently a stranger to the machine, to judge from his awkwardness) was desired to strike down the knob which put the portable Fire Annihilator in action. He did so; and immediately the thick white vapour began to gush forth. The boy carried the machine, with very little effort, to within four or five feet of the flames. Instantly the flames changed colour, as though with a sort of ghastly purple horror of their destroyer—and, in a few seconds, down they sank, and became nothing. There lay the black mixture, looking as if it had never been disturbed. But the machine, meantime, went on vomiting forth its vapour, with surplus power, like the escape-pipe of a steam-engine, and the boy being in a state of confusion, was bringing the machine back among the company assembled round, who all begun to retreat, when somebody connected with the Works told him to let it off against the dead wall. While this was taking place, the same individual remarked aloud, that the vapour could not only be breathed after it had ascended and extinguished a fire, but would not burn even as it gushed forth fresh and furious from the machine. As he said this, he passed his hand through it once or twice. Mr. Diggs suddenly thought he had a last chance,—and, rushing forward, passed his hand (hoping he might be dreadfully scorched) through the fierce vapour as it rushed out. Actually, he was not at all scorched. It was only rather hot. He passed his hand backwards and forwards twice more—a sort of greasy and rather dirty warm moisture covered his hand—this was all. John Diggs was fairly conquered—admitted it to himself—and, seeking out Mr. Phillips, went honestly up to him, and shook him heartily by the hand—saying, with a laugh, that if all was fairly done, and no necromancy, he had witnessed a great fact, and he congratulated him.