The mould being reopened presently displayed a large, heavy lantern, whose curiously elaborate flutings and pencillings were, as the intelligent artisan averred, arranged upon the principle of the famous Fresnel light, whose introduction some years ago marked an epoch in the history of light-houses.
"Why, Miss, these little up-and-down marks, that you'd take it were just put in for fancy," said William Greaves, "have got a patent on 'em, and no one else could put 'em into a lantern without being prosecuted."
"But why? What difference do they make?"
"Why, Miss, every one of them fingerings makes a lens; you see it's just the same inside as out, and it sort of spreads the light. That a'n't the way to call it, but that's the idea; for the man that got it up was down here, and I talked with him."
"And what are they for?"
"For ships' lanterns, Ma'am. They take this round lantern, when it's all done here, and split it in two halves up and down, and then put one on each side a vessel's bows just like the lamps on a doctor's gig, and the bowsprit runs out between just like the horse does in the gig."
At this juncture a small boy rushed up, and, thrusting a stick into the still red-hot lantern, dexterously tilted it up and carried it away to a furnace of different construction from the first, into one of whose open doors he thrust it, and then returned to wait for another.
This furnace, called a flashing-furnace, was round like the first, and was fitted with eight or ten doors, from all of which the flames rushed eagerly, and in a very startling fashion.
"This is fed constantly with coal-oil," expounded Cicerone. "It is brought in pipes, as you see, and drips down inside. These doors are called 'glory-holes'"——
"Aureoles, perhaps," suggested Optima, in a whisper.