quite certain whether we
obtained the ammonia from the coke or from the nitrogen of the
atmosphere, or from both. For this purpose we made for every
experiment carried on by a mixture of nitrogen or air with steam
another experiment with steam alone, carefully excluding nitrogen from
the apparatus. A very large number of experiments carried on at
carefully determined temperatures, ranging from 500 deg. to 1,200 deg.C., and
in which the directions given by the various inventors were most
carefully observed, all led to the same result, viz., that the
quantities of ammonia obtained were the same whether nitrogen was
introduced into the apparatus with the steam or whether steam alone
was used, thus proving conclusively that the ammonia obtained was
derived from the nitrogen contained in the coke.

Further, on carefully determining the nitrogen in the coke used, it
was found that the quantity of ammonia we had obtained in burning coke
in a current of nitrogen and steam very nearly corresponded with the
total nitrogen in the coke, so that we subsequently made our nitrogen
determinations in the coke by simply burning it in a current of steam.

A process belonging to this class, proposed by Hugo Fleck, in which a
mixture of carbonic oxide, steam, and nitrogen is made to pass over
lime at a moderate red heat in order to obtain ammonia, was also
carefully tried. It was claimed for this process that it produced
nascent hydrogen at temperatures at which the ammonia is not
dissociated, and for this reason succeeded where others had failed. We
found that a considerable amount of hydrogen was obtained in this way
at a temperature not exceeding 350 deg.C., and that the reaction was
nearly complete at 500 deg.C.; but although we tried many experiments over
a great range of temperatures, we never obtained a trace of ammonia by
this process.

Among experiments with processes of the second class, based upon the
formation of nitrides and their subsequent decomposition, the nitrides
of boron and titanium had received most attention from inventors. The
nitride of boron, which is obtained by treating boracic acid with
carbon in the presence of nitrogen, when acted upon by steam, forms
boracic acid again and yields the whole of its nitrogen in the form of
ammonia, but the high temperature at which the first reaction takes
place, and the volatility of boracic acid in a current of steam, make
it impossible to utilize this reaction industriall