y.

There seemed to be a better chance for a process patented by M.
Tessier du Mothay, who proposed to bring a mixture of nitrogen and
hydrogen into contact with titanium nitride and thus to form ammonia
continuously. Titanium is the only element of which we know at present
several combinations with nitrogen, and the higher of these does, on
being acted upon by a current of hydrogen at an elevated temperature,
produce ammonia and a lower nitride of titanium; but this lower
nitride does not absorb nitrogen under any of the conditions under
which we tried it, which explains the fact that if we passed a current
of hydrogen and nitrogen over the higher nitride, we at first obtained
a quantity of ammonia corresponding to the quantity which the nitride
would give with hydrogen alone, but that the formation of ammonia then
ceased completely.

Thus far we had quite failed to get the nitrogen of the air into
action.

With the third class of processes, however, based upon the formation
in the first instance of cyanides, we found by our very first
experiments that the nitrogen of the atmosphere can be easily led into
combination. A few experiments showed that the cyanide of barium was
much more readily formed than any other cyanide; so we gave our full
attention from this time to the process for obtaining ammonia by means
of cyanide of barium invented by MM. Margueritte and Sourdeval. This
process consists in heating a mixture of carbonate of barium with
carbon in the presence of nitrogen, and subsequently treating the
cyanide of barium produced with steam, thus producing ammonia and
regenerating the carbonate of barium. A great difficulty in this
process is that the carbonate of barium fuses at high temperatures,
and when fused attacks fireclay goods very powerfully.

We found that this can be overcome by mixing the carbonate of barium
with a sufficient quantity of carbon and a small quantity of pitch,
and that in this way balls can be made which will not fuse, so that
they can be treated in a continuous apparatus in which the broken
briquettes can be charged from the top, and after treatment can be
withdrawn from the bottom.

We found that the formation of cyanides required a temperature of at
least 1,200 deg. C., and proceeded most readily at 1,400 deg. C., temperatures
which, although difficult to attain, are still quite within the range
of practical working, and we found no difficulty in obtaining a
product containing