100 RESEARCHES ON THE AMMONIAC A L COMPOUNDS. 
of the same salts are added to the dry white precipitate, only 
all the ammonia is now liberated, and the liquor contains 
chloride of potassium and free potassa. When white precipi- 
tate is heated to a temperature below a red heat, in a tube 
closed at one end, it is decomposed ; calomel sublimes and 
ammonia, and nitrogen is given off, together with watery 
vapor. 
Having, by careful preparation, obtained an article upon 
which reliance could be placed, Prof. Kane trusted to dimi- 
nish the errors of analysis by taking the average of numerous 
results, these results being obtained by processes differing in 
principle, thus avoiding any liability of the same error per- 
vading the whole. 
As when ammonia is added to a solution of bichloride of 
mercury, the whole of the mercury is precipitated, hydrochlo- 
rate of ammonia remaining in solution, itis evident that know- 
ing the quantity of mercury contained in the bichloride used, 
and ascertaining the amount of chlorine abstracted by the am- 
monia and held in solution, the whole of the mercury, and the 
residue of the chlorine, will be the amount of these two sub- 
stances in the precipitate obtained, the weight of which is to 
be ascertained when perfectly dry. 
Taking, therefore, 100 grains of bichloride, which contains 
74.09 of mercury, the average result of five different experi- 
ments gave, 
Precipitate. Chlorine. Mercury, 
93.1 12.91 74.09 
Or 100 parts of the precipitate contains 
Ch 13.87 
Hg 79.57 
Leaving a deficit of 6.56 
100.00 
to be accounted for as oxygen and ammonia, or as amidogen. 
The decomposition of the white precipitate by heat, affords 
another mode of determining the amount of the ingredients 
