340 Dr. Thomas Thomsons 



Canada, which he distinguished by the name of Grey chlorite. 

 This specimen bears a near relation to the Weissite of 

 Trolle Wachtmeister. 



Its colour is ash grey, with a slight tint of blue. 



The structure is slaty — Lustre resinous. Fracture even. 

 Opaque. Does not feel soapy; yet in Canada it goes by 

 the name of soapstone. 



Hardness L75. It is readily scratched by the nail, and 

 ajDpears softer than selenite. 



Specific gravity 2-8263. 



It was analyzed, at my request, by Mr. John Tennant, in 

 my laboratory, who obtained the following constituents : — 



Atoms. 



Silica, .... 55-05 27.5 



Alumina, . . . 22-60 10 



Protoxide of iron, 12-60 2-8 



Lime .... 1.40 0-4 



Magnesia with ) 5 . 7Q 2 . 2 

 trace oi manganese, ^ 



Water, .... 2-25 2 



99-6 



The formula indicated by these proportions is 2 A1S 2 + 

 (1/ + i Mg) S* 



Trolle Wachtmeister found the constituents of his Weis- 

 site to be, 



Atoms. 



Silica, 59-69 29-84 



Alumina .... 21-70 9-64 



Magnesia .... 8-99 3-60 



Protoxide of iron, . 1-43 0-31 



Protox. of manganese, 0-63 0-14 



Potash 4-10 0-68 



Soda 0-68 0-17 



Oxide of zinc . . . 0'30 0.05 



Water with ammonia, 3-20 2*84 



100-72 

 The formula from these proportions is, 



2 A1S« + (f T Mg + .& K + T V/) S* + | Aq. 

 I think it very probable, from comparing the analyses 

 of these two minerals, that the only essential constituents 



