facilitating the action; it undergoes no change in the process), and
connected with the top of the vessel is a bent glass tube (D), which may
remind you of the pipe which was connected with the gun barrel in our
furnace experiment, and which now passes under the jar (F). I have now
adjusted this apparatus, and we will proceed to affect the water in some
way or other. In the other case, I sent the water through a tube which was
made red-hot; I am now going to pass the electricity through the contents
of this vessel. Perhaps I may boil the water; if I do boil the water, I
shall get steam; and you know that steam condenses when it gets cold, and
you will therefore see by that whether I do boil the water or not.
Perhaps, however, I shall not boil the water, but produce some other
effect. You shall have the experiment and see. There is one wire which I
will put to this side (A), and here is the other wire which I will put to
the other side (B), and you will soon see whether any disturbance takes
place. Here it is seeming to boil up famously; but does it boil? Let us
see whether that which goes out is steam or not. I think you will soon see
the jar (F) will be filled with vapour, if that which rises from the water
is steam. But can it be steam? Why, certainly not; because there it
remains, you see, unchanged. There it is standing over the water, and it
cannot therefore be steam, but must be a permanent gas of some sort What
is it? Is it hydrogen? Is it anything else? Well, we will examine it. If
it is hydrogen, it will burn. [The Lecturer then ignited a portion of the
gas collected, which burnt with an explosion.]

[Illustration: Fig. 19]

It is certainly something combustible, but not combustible in the way that
hydrogen is. Hydrogen would not have given you that noise; but the colour
of that light, when the thing did burn, was like that of hydrogen: it
will, however, burn without contact with the air. That is why I have