XII. A Chemical Analysis of Sodalite, a new Mineral from 
Greenland.. By Tuomas Tuomson, M.D. F.R.S. E. 
Fellow of the Imperial Chirurgo-Medical Academy of Pe- 
tersburgh. 
[Read Nov. 5. 1810.] 
HE mineral to which I have given the name of Sodalite, 
“was alfo put into my hands by Mr Atztan. In the 
- Greenland collection which he purchafed, there were feveral 
fpecimens of a rock, obvioufly primitive. In the compofition 
of thefe, the fubftance of which I am about to treat, formed a 
conftituent, and, at firft appearance, was taken for felfpar, to 
which it bears‘a very ftriking refemblance. 
Tuis rock is compofed of no lefs than five different foffils, 
namely, garnet, hornblende, augite, and two others, which form 
the pafte of the mafs. Thefe are evidently different minerals ; 
but in fome fpecimens, are fo intimately blended, that it requi- 
red the fkill of Count Bournon to make the difcrimination, 
and afcertain their real nature. Even this diftinguifhed mine- 
ralogift was at firft deceived by the external afpect, and confi- 
dered the pafte as common lamellated felfpar, of a greenith co- 
~lour. But a peculiarity which prefented itfelf to Mr Arian, 
in one of the minerals, induced him to call the attention of 
Count Bournon more particularly to its conftracion. 
On. a clofer examination of the mimeral, M. de Bournon 
found that fome fmall fragments, which he had detached, pre- 
aCe fented 
