136 Analysis of some Steatites. 



15. The residuum of No. 13 was found to be pure silex, 



which, after having been dried and roasted, weighed 0*30. 

 100 parts of this mineral therefore contain 



Magnesia 28 



Carbonic acid 27 



Silex 30-8 



Oxide of iron 11*2 



Lime 08 



Water 0*3 



98-1 

 Loss 1*9 



100 



The most remarkable circumstance is, that this mineral 

 .contains no alumine, and includes a large quantity of iron. 

 The outward appearance of the mass would lead us to susr 

 pect the former substance, and its light colour by no means 

 indicates so large a quantity of the second. Probably the 

 carbonic acid combining with the oxide of iron conceals its 

 presence. 



M. Klaproth, who had before analysed a specimen of 

 this schist, found in it : 



Silex ....66*5 



Alumine 7 



Magnesia 1*5 



Lime 1*2.5 



Oxide of iron 2-5 



Water 19 



♦ 97*75 

 Loss 2*25 



100 



XXII. Comparative Analysis of some Varieties of Steatite , 

 or Talc. By M. yAuaup;LiN*, 



JL he smoothness and unctuosity of the stones called stea- 

 tites has been commonly ascribed to the presence of mag- 



* From Annates de Chimie, tome xlix. 



nesia, 



