[potassium and sodium. 
285 
matter. The following is the mode of proceeding : — A 
caustic solution of alkali, in water or other convenient li- 
quid, is first made boiling hot, and to it, while boiling, as 
much animal matter is added as it will readily dissolve; the 
solution is next evaporated to dryness, and the masspreserv- 
ed in that state for use. When a portion of this mass is put 
into each of the heated vessels, except the last, of such a 
series as has been described, and the last heated vessel is 
charged with carbon, mixed with some convenient com- 
pound of an alkaline metal, as before stated, then the am- 
monia, which escapes from any one of the vessels in the 
series, will have to pass through one or more subsequent 
vessels, and thus tend to suffer decomposition; the resulting 
nitrogen being converted into cyanogen, and then being ab- 
sorbed. This admits of the cheaper kinds of animal matter 
being used — such as the undried flesh and viscera of car- 
rion, and old woollen flock^andrags, which, by reason either 
of humidity or too great volume, cannot conveniently be 
mixed in their natural state with red-hot alkali. The pa- 
tentee claims this modification of the process as part of the 
invention for which this patent has been granted. Some- 
times the mass resulting from the desiccation of the solution 
of animal matter in caustic alkali is put into red-hot open 
pots; in this case, much ammonia is lost, but the improve- 
ment which is introduced by replacing the ordinary mecha- 
nical admixture by an intimate chemical combination, affords 
a greater product in prussiate than can be obtained from an 
equal quantity of animal matter treated in the ordinary way. 
Chemist, from Newton } s Journal. 
