ght, to that of the two gases introduced into the
globe.

CAROLINE.

And what was the greatest quantity of water ever formed in this
apparatus?

MRS. B.

Several ounces; indeed, very nearly a pound, if I recollect right; but
the operation lasted many days.

EMILY.

This experiment must have convinced all the world of the truth of the
discovery. Pray, if improper proportions of the gases were mixed and set
fire to, what would be the result?

MRS. B.

Water would equally be formed, but there would be a residue of either
one or other of the gases, because, as I have already told you, hydrogen
and oxygen will combine only in the proportions requisite for the
formation of water.

EMILY.

Look, Mrs. B., our experiment with the Voltaic battery (PLATE VIII. fig.
2.) has made great progress; a quantity of gas has been formed in each
tube, but in one of them there is twice as much gas as in the other.

MRS. B.

Yes; because, as I said before, water is composed of two volumes of
hydrogen to one of oxygen--and if we should now mix these gases together
and set fire to them by an electrical spark, both gases would entirely
disappear, and a small quantity of water would be formed.

There is another curious effect produced by the combustion of hydrogen
gas, which I shall show you, though I must acquaint you first, that I
cannot well explain the cause of it. For this purpose, I must put some
materials into our apparatus, in order to obtain a stream of hydrogen
gas, just as we have done before. The process is already going on, and
the gas is rushing through the tube--I shall now kindle it with the
taper----

EMILY.

It burns exactly as it did before---- What is the curious effect which
you were mentioning?

MRS. B.

Instead of the receiver, by means of which we have just seen the drops
of water form, we shall invert over the flame this piece of tube, which
is about two feet in length, and one inch in diameter (PLATE VIII.
fig. 7.); but you must observe that it is open at both ends.

EMILY.

What a strange noise it makes! something like the AEolian harp, but not
so sweet.

CAROLINE.

It is very singular, indeed; but I think rather too powerful to be
pleasing. And is not this sound accounted for?

MRS. B.

That the percussion of glass, by a rapid stream of gas, should produce a
sound, is not extraordinary: but the sound here is so peculiar, that no
other gas has a similar effect. Perhaps it is owing to a