Page:The chemical history of a candle.djvu/210

208 spoiled the other. When the metals are laid one upon the other, and folded together and heat applied, you will not only see that the platinum runs to waste, but that at the time when the platinum and lead are combined there is ignition produced—there is a power of sustaining combustion. I have taken a large piece, that you may see the phenomenon on a large scale. You saw the ignition and the explosion which followed, of which we have here the results—the consequence of the chemical affinity between the platinum and the metals combined with it, which is the thing upon which Deville founds his first result.

When he has melted these substances and stirred them well up, and so obtained a complete mixture, he throws in air upon the surface to burn off all the sulphur from the remaining sulphuret of lead; and at last he gets an ingot of lead with platinum—much lead, comparatively, and little platinum. He gets that in the crucible with a lot of scoriae and other things, which he treats afterwards. It is that platiniferous lead which we have to deal with in our future process. Now, let me tell you what he does with it. His first object is to get