2. That the diminution of volume of nitrous gas placed
in contact with water, is owing to a simple solution
of it in that fluid.
3. That at the temperature of 212°, nitrous gas is
incapable of remaining in combination with water.
Humbolt’s opinion relating to the decomposition of nitrous gas by
water, is founded upon the disengagement of vapor from distilled water
impregnated with nitrous gas, by means of lime, which became white in
the proximity of the muriatic acid. But this is a very imperfect, and
fallacious test, of the presence of ammoniac. I have this day, April
2, 1800, heated 4 cubic inches of distilled water, impregnated with
nitrous gas, with caustic lime; the vapor certainly became a little
whiter when held over a vessel containing muriatic acid; but the vapor
of distilled water produced precisely the same appearance,[111] which
was owing, most likely, to the combination of the acid with the
aqueous vapor. Indeed, when I added a particle of nitrate of ammoniac,
which might have equalled one twentieth of a grain, to the lime and
impregnated water, the increased whiteness of the vapor was but barely
perceptible, though this quantity of nitrate of ammoniac is much more
considerable than that which could have been formed, even supposing the
nitrous gas decomposed.
[111] As carbonic acid and ammoniac are both products of animalisation,
is it not probable that our common waters particularly those in, and
near towns and cities, contain carbonate of ammoniac? If so, this
salt will always exist in them after distillation. In the experiments
on carbonate of ammoniac, to which I have often alluded, I found, in
distilling a solution of this salt in water, that before half of the
water had passed into the recipient, the carbonate of ammoniac had
sublimed; so that the distilled solution was much stronger than before,
whilst the water remaining in the retort was tasteless. Will this
supposition at all explain Humbolt’s mistake?