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 rid of the lead. He has thrown out all
the iron, and a number of other things, and he has got this kind of
compound indicated in the table.
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