nothing; if I tried a smaller piece, I should do little or
nothing; and if I tried a still smaller piece, I should do little or
nothing; yet I have a condition which will represent what Deville carries
to the highest possible extent, and which we all carry to the highest
extent, in the use of the blowpipe. Suppose I take this piece of antimony:
I shall not be able to melt it in that flame of the candle by merely
holding it there; yet, by taking pains, we can even melt a piece of
platinum there. This is a preparation which I made for the purpose of
proving the fusibility of platinum in a common candle. There is a piece of
wire, drawn by that ingenious process of Dr. Wollaston's, not more than
the three-thousandth part of an inch in diameter. He put the wire into the
middle of a cylinder of silver, and drew both together until the whole
compound was exceedingly thin; and then he dissolved away the silver by
nitric acid. There was left in the centre a substance which I can scarcely
see with an eye-glass, but which I know is there, and which I can make
visible, as you see, by putting it into the candle, where the heat makes
it glow like a spark. I have again and again tried this experiment
up-stairs in my own room, and have easily fused this platinum-wire by a
common candle. You see we have, therefore, heat enough in the candle, as
in the voltaic battery, or in the highly-exalted combustion of the
blowpipe, but we do not supply a continuous source of heat. In the very
act of this becoming ignited, the heat radiates so fast that you cannot
accumulate enough to cause the fusion of the wire, except under the most
careful arrangement. Thus I cannot melt that piece of antimony by simply
putting it into the candle; but if I put it upon charcoal, and drive the
fiery current against it, there will be heat enough to melt it. The beauty
of the blowpipe is, that it sends hot air (making hot air by the
combustion of the flame) against the thing to be heated. I have only to
hold the antimony in the course of that current, and particle by particle
of the current impinges upon the antimony, and so we get it melted. You
now see it red-hot, and I have no doubt it will continue to burn if I
withdraw it from the flame and continue to force the air on it. Now, you
see it burning without any heat but that of its own combustion, which I am
keeping up by sending the air against it. It would go out in a moment if I
took away the current of air from