M. C. Lea on Urea from Ferrocyanid of Potassium. 179 
protochlorid was added until reaction ceased. The whole was 
then distilled with caustic potash and the resulting gases con- 
ducted into dilute chlorhydric acid, which by evaporation left 
only a film of substance—this gave on examination distinct indi- 
cations of ammonia. 
Reduction by sulphydric acid—A large quantity of sulphydric 
acid was conducted through nitrite of ethyl. Slight effervescence 
was produced and much sulphur deposited. The liquid filtered 
from the sulphur proved to contain a large quantity of ammonia, 
but no ethylamine, di-, or triethylamine, although the mode of 
examination employed would have detected a very small quan- 
tity if present. After the removal of the ammonia, the solution 
heated with Pt Cl 2 gave a small quantity of a brown precipitate 
of a platinum salt, which when heated glowed for a long time 
This result therefore, as far as to the production of ammonia, 
Corresponds with that obtained by M. Emile Kopp,* although, as 
that chemist employed sulphydrate of ammonia instead of sul- 
phy dric acid, it does not appear that the production of ammonia 
y the reaction itself, could be positively established. 
Reduction by ferrous acetate.—Nitrite of ethyl was added to 
about three times its bulk of ordinary acetic acid, and sufficient 
alcohol to make them mix. To this mixture iron filings were 
added. A powerful action set in without aid of heat. Deut- 
oxyd of nitrogen was evolved in considerable quantity. When 
action had ceased, the resulting liquid was filtered, evaporated 
with chlorhydrie acid and distilled with caustic potash. The 
distillate contained only traces of ammonia. 
The effect of the reducing agents on nitrite of ethyl is there- 
fore very different. Only with sulphydric acid was any consid- 
erable quantity of ammonia produced, and only with ferrous 
acetate was deutoxyd of nitrogen evolv 
3. On the Preparation of Urea from Ferrocyanid of Potassium, 
In the preparation of urea by Wéhler’s method the amount 
obtained wis falls short of that which should theoretically be 
Produced. Having remarked that even when the operation is 
* Gerhardt, Chimie Org., ii, 347. 
