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Rh a curiosity to know how air may be made to act on combustion, or how the air-draught power has been developed, let him study the simple economy and arrangement of these furnaces. There is a large range of about twenty of them, all under draught if not blast at once. Nebuchadnezzar's furnace, seven times heated, was a kitchen fire compared with one of these for heat. Each is charged with its covered pot full of blistered steel with coal to match. Their lidded mouths dull the roaring sound of the terrible combustion, but the furnace-men show by their looks the intensity of the heat. The pouring-off sight is really thrilling. When the lid is removed from each furnace, and the pot of molten metal lifted out by a pair of long-handled tongs with rounded jaws, even a spectator must have steady nerves to look at it. To speak of white heat, or the heat of molten gold or silver would be like comparing the flame of a yellow tallow candle with the magnesian light. As the stalwart men, naked to their waists, remove the cover from the pot and pour the fluid into flasks for ingots, the brightness is almost blinding even to one standing at the distance of several paces. As the whizzing stream runs into the mould, it emits a sparkling spray dashed with rainbow tints from various ignited gases. When the metal is sufficiently cooled and hardened, it is taken from the moulds in ingots or bars of