How shall we get at this? I myself know plenty of ways, but I want
_you_ to get at it from the association in your own minds of what I have
already told you.
I think you can see a little in this way. We had just now the case of a
substance which acted upon the water in the way that Sir Humphrey Davy
shewed us[13], and which I am now going to recall to your minds by making
again an experiment upon that dish. It is a thing which we have to handle
very carefully, for you see, if I allow a little splash of water to come
upon this mass, it sets fire to part of it; and if there were free access
of air, it would quickly set fire to the whole. Now, this is a metal--a
beautiful and bright metal--which rapidly changes in the air, and, as you
know, rapidly changes in water. I will put a piece on the water, and you
see it burns beautifully, making a floating lamp, using the water in the
place of air. Again, if we take a few iron filings or turnings, and put
them in water, we find that they likewise undergo an alteration. They do
not change so much as this potassium does, but they change somewhat in the
same way; they become rusty, and shew an action upon the water, though in
a different degree of intensity to what this beautiful metal does: but
they act upon the water in the same manner generally as this potassium.
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