nsible quantity of the gases can be collected.

EMILY.

The decomposition of water in this way, slow as it is, is certainly very
striking; but I confess that I should be still more gratified, if you
could shew it us on a larger scale, and by a quicker process. I am sorry
that the decomposition of water by charcoal or metals is attended with
so much inconvenience.

MRS. B.

Water may be decomposed by means of metals without any difficulty; but
for this purpose the intervention of an acid is required. Thus, if we
add some sulphuric acid (a substance with the nature of which you are
not yet acquainted) to the water which the metal is to decompose, the
acid disposes the metal to combine with the oxygen of the water so
readily and abundantly, that no heat is required to hasten the process.
Of this I am going to shew you an instance. I put into this bottle the
water that is to be decomposed, as also the metal that is to effect that
decomposition by combining with the oxygen, and the acid which is to
facilitate the combination of the metal and the oxygen. You will see
with what violence these will act on each other.

CAROLINE.

But what metal is it that you employ for this purpose?

MRS. B.

It is iron; and it is used in the state of filings, as these present a
greater surface to the acid than a solid piece of metal. For as it is
the surface of the metal which is acted upon by the acid, and is
disposed to receive the oxygen produced by the decomposition of the
water, it necessarily follows that the greater is the surface, the more
considerable is the effect. The bubbles which are now rising are
hydrogen gas----

CAROLINE.

How disagreeably it smells!

MRS. B.

It is indeed unpleasant, though, I believe, not particularly hurtful. We
shall not, however, suffer any more to escape, as it will be wanted for
experiments. I shall, therefore, collect it in a glass-receiver, by
making it pass through this bent tube, which will conduct it into the
water-bath. (PLATE VIII. fig. 3.)

EMILY.

How very rapidly the gas escapes! it is perfectly transparent, and
without any colour whatever. --Now the receiver is full----

MRS. B.

We shall, therefore, remove it, and substitute another in its place. But
you must observe, that when the receiver is full, it is necessary to
keep it inverted with the mouth under water, otherwise the gas would
escape. And in order that it may not be in the way, I introduce within
the bath, un