DR T. THOMSON'S Analysis of some Minerals, 477 

 These constituents are equivalent to 



22 atoms silica, 

 ] 2 atoms alumina, 



1 atom potash, 



8 atoms water. 



Killinite therefore may be considered as a compound of 



* , ' ; i 



12 atoms sesquisilicate of alumina, 

 1 atom quatersilicate of potash, 

 8 atoms water. 



Its symbol is 12A/S 14 + KS 4 + 8Agr. 



The alkali was examined with great care, and was found to 

 be pure potash. This was requisite, because in the vein, killi- 

 nite is intermixed with spodumene, the alkali of which we found 

 to be lithia, without any admixture of potash or soda. I was 

 disposed at first to suspect that killinite might be only a variety 

 of spodumene. But the external characters and the consti- 

 tuents are both incompatible with such a supposition. It must 

 therefore be admitted into the system as a distinct species. 



The spodumene which accompanies the killinite was ana- 

 lyzed two different times by Captain LEHUNT. The consti- 

 tuents found were almost identical with the specimen from Uto, 

 in Sweden, analyzed by STROMEYEB *. I subjoin both, to enable 

 the reader to compare the two. 



Untersuchunger, p. 426. 



3 o2 



