incidental to this process over and
above the profit arising from the manufacture of sulphate of ammonia,
viz., the absolute impossibility of producing smoke and the great
regularity of the heating resulting from the use of gas, are,
therefore, as far as I can see for the present, only available for
large consumers of cheap fuel.

We have tried many experiments to produce hydrochloric acid in the
producers, with the hope of thereby increasing the yield of ammonia,
as it is well known that ammonium chloride vapor, although it consists
of a mixture of ammonia gas and hydrochloric acid gas, is not at all
dissociated at temperatures at which the dissociation of ammonia alone
has already taken place to a considerable extent.

I had also hoped that I might in this way produce the acid necessary
to combine with the ammonia at very small cost. For this purpose we
moistened the fuel used with concentrated brine, and also with the
waste liquors from the ammonia soda manufacture, consisting mainly of
chloride of calcium; and we also introduced with the fuel balls made
by mixing very concentrated chloride of calcium solution with clay,
which allowed us to produce a larger quantity of hydrochloric acid in
the producer than by the other methods.

We did in this way succeed in producing hydrochloric acid sometimes
less and sometimes more than was necessary to combine with the
ammonia, but we did not succeed in producing with regularity the exact
amount of acid necessary to neutralize the ammonia. When the ammonia
was in excess, we had therefore to use sulphuric acid as before to
absorb this excess, and we were never certain that sometimes the
hydrochloric acid might not be in excess, which would have
necessitated to construct the whole plant so that it could have
resisted the action of weak hydrochloric acid--a difficulty which I
have not ventured to attack. The yield of ammonia was not in any case
increased by the presence of the hydrochloric acid. This explains
itself if we consider that there is only a very small amount of
ammonia and hydrochloric acid diffused through a very large volume of
other gases, so that the very peculiar protective action which the
hydrochloric acid does exercise in retarding the dissociation of
ammonia in ammonium chloride vapor, where an atom of ammonia is always
in contact with an atom of hydrochloric acid, will be diminished
almost to zero in such a dilute gas where the atoms of hydrochloric
acid