HEAVY CARBONATE AND CALCINED MAGNESIA. 117 
product does not contain the least trace of any compound 
of cyanogen. 
We may add, that the formation of hydrocyanic acid 
during the reaction of nitric acid on certain organic matters, 
is not a recent observation. In 1839, M. Gauthier de Clau- 
bry proved the presence of hydrocyanic acid in the alco- 
hol left after the preparation of fulminates ; and in 
tfie ^following year, M. Sobrero showed that it was also 
formed on distilling nitric acid with volatile oils, or even 
with some resins. M. Thenard also, some time ago, an- 
nounced that this acid was one of the products of the reac- 
tion of nitric acid" on sugar, gum, &c. Nevertheless, the 
observations made by M. Dalpaiz, with reference to the 
particular case to which he has alluded, are interesting and 
valuable. 
Journal de Pharmacie and Pharm. Journal. 
ART. XXVIII — ON THE HEAVY CARBONATE AND CAL- 
CINED MAGNESIA. By Mr. Richard Phillips, Jun. 
My attention having been directed to the above named 
preparations, I was induced to make some experiments upon 
them, the results of which may, perhaps, be interesting to 
the Society. 
I found that upon one atom, or 123 parts, of crystallized 
sulphate of magnesia being boiled with one atom, or 59 
parts, of sesquicarbonate of ammonia, the half atom of car- 
bonic acid was expelled from the sesquicarbonate of am- 
monia, and a dense carbonate of magnesia was precipitated. 
This, however, when washed, dried, and calcined, lost its 
density. 
I repeated this experiment with this difference, that I 
evaporated the precipitate and the sulphate of ammonia 
VOL. X. NO. II. 1 1 
