ammonia and sulphuric acid are resulting products, in the compound
state of sulphate of ammonia. The formation of the ammonia produced in
the process is probably due to the decomposition of nitrogenous bodies
contained in solution in the liquor--the sulphocyanide, for instance;
the nitrogen being given off in the form of ammonia. Of the sulphuric
acid produced, we look upon the sulphureted hydrogen as the source,
also any sulphites existing in the liquor, which in their volatile
state take up the atom of oxygen necessary for their conversion into
sulphate.

[Illustration]

The apparatus used in working the process consists of a tower still,
containing a number of superposed trays about 3 or 4 inches apart,
with a lipped hole through the bottom of each at the side. The trays
are so placed in the tower that the holes are at alternate sides. The
liquor passes into the top of the still, and zigzags down through the
series of trays, as in an ordinary Coffey still. The bottom tray
differs from the rest; being much deeper, and having holes through it
connecting it with the furnace, which is set immediately below it. The
products of combustion of the fuel are caused to pass from the furnace
up through the holes in the trays in the still, and, together with the
gases evolved from the liquor, are directed into the saturator, where
the sulphate of ammonia is obtained either in solution or in the
crystalline state.

Where the process is at present being worked, an exhauster is used to
draw the furnace gases through the still; but it might be advantageous
to use a blower.