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216 through it. Now, then, you see these beautiful sparks: you have not only a beautiful kind of combustion, but you see the iron is being driven off, not producing smoke, but burning in a fixed condition. How different this is from the action of some other metals—that piece of antimony, for instance, which we saw just now throwing off abundance of fumes. We can, of course, burn away this iron by giving plenty of air to it; but with the bodies which Deville wants to expose to this intense heat he has not that means: the gas itself must have power enough to drive off the slag which forms on the surface of the metal, and power to impinge upon the platinum so as to get the full contact that he wants for the fusion to take place. We see here, then, the means to which he resorts oxygen, and either coal-gas or water-gas, or pure hydrogen, for producing heat, and the blowpipe for the purpose of impelling the heated current upon the metals.

I have two or three rough drawings here, representing the kind of furnaces which he employs. They are larger, however, than the actual furnaces he uses. Even the furnace in which he carries on that most serious