6 



only in one iu Killinite ; 3dly, by tlie greater degree of hardness, 

 since it scratches glass; 4tlily, by its lighter colour, which is green- 

 ish white ; and 5thly, by its appearances before the blow-pipe ; 

 for before a strong flame Spodinnene at first swells, then falls 

 into a whitish powder, and if tlie flame be urged on small pieces, 

 '"they are readily converted into transparent glass globules ; while Kil- 

 linite, Avithout presenting the peculiar appearance of ashes before 

 the blow-pipe, (whence the name of Spodumene is derived,) never 

 becomes transparent, but is changed into a white opaque enamel. 



The following chemical analysis of Killinite was kindly under- 

 taken and performed by my friend Doctor Barker, Professor of 

 Chemistry in the University. It is unnecessary to state to the 

 ^members of this Academy, ("most of whom well know,) what en- 

 ■tire confidence niay be placed in his knowledge and accuracy. 



Various experiments, instituted for the purpose, indicated the 

 chief constituents of this mineral to be Silex, Alumine, Potash, 

 and oxide of Iron. To ascertain the relative quantity of these 

 substances, different methods were employed. By the action of 

 Sulphuric acid, the quantities of Silex and Potash chiefly were de- 

 termined. By solution in caustic Potash, and the usual subsequent 

 treatment, the quantity of Alumine was ascertained, and the re. 

 suits obtained by the Sulphuric Acid at the same time confirmed. 

 Another process, in which the chief agent was Nitrate of Barytes, 

 •served to establish the presence of Potash, and to guard against 

 error in estimating the quantity of this alkali. 



Diluted nitric acid exerted no action on the mineral. One hun- 

 dred grains of it reduced to fine powder, and heated to redness in a 

 platina dish during half an liour, suffered a loss of weight equal to 

 five grains, arising from the expulsion of water (A.) 



