n and two volumes of hydrogen. This mixture is exactly
of the same nature as the gas we just now obtained from the voltaic
battery: it would be far too much to burn at once; I have therefore
arranged to blow soap-bubbles with it, and burn those bubbles, that we may
see by a general experiment or two how this oxygen supports the combustion
of the hydrogen. First of all, we will see whether we can blow a bubble.
Well, there goes the gas [causing it to issue through a tobacco-pipe into
some soap-suds]. Here I have a bubble. I am receiving them on my hand: and
you will perhaps think I am acting oddly in this experiment; but it is to
shew you that we must not always trust to noise and sounds, but rather to
real facts. [Exploding a bubble on the palm of his hand.] I am afraid to
fire a bubble from the end of the pipe, because the explosion would pass
up into the jar and blow it to pieces. This oxygen then will unite with
the hydrogen, as you see by the phenomena, and hear by the sound, with the
utmost readiness of action, and all its powers are then taken up in its
neutralisation of the qualities of the hydrogen.

So now I think you will perceive the whole history of water with reference
to oxygen and the air, from what we have before said. Why does a piece of
potassium decompose water? Because it finds oxygen in the water. What is
set free when I put it in the water, as I am about to do again? It sets
free hydrogen, and the hydrogen burns; but the potassium itself combines
with oxygen; and this piece of potassium, in taking the water apart--the
water, you may say, derived from the combustion of the candle--takes away
the oxygen which the candle took from the air, and so sets the hydrogen
free; and even if I take a piece of ice, and put a piece of potassium upon
it, the beautiful affinities by which the oxygen and the hydrogen are
related are such, that the ice will absolutely set fire to the potassium.
I shew this to you to-day, in order to enlarge your ideas of these things,
and that you may see how greatly results are modified by circumstances.
There is the potassium on the ice, producing a sort of volcanic action.

It will be my place, when next we meet, having pointed out these anomalous
actions, to shew you that none of these extra and strange effects are met
with by us--that none of these strange and injurious actions take place
when we are burning, not merely a candle, but gas in our streets, or fuel
in our fireplaces,