DR T. THOMSON on Asbestus, Chlorite, and Tak. 385 



Silica, ... . . . 42.320 43.884 



Magnesia, 25.680 24.144 



Alumina, . . . . . 9.384 9.872 



Lime, 4.680 



Protoxide of iron, . . 1.083 



Water, 16.960 21.228 



100.107 99.128 



- . - ^- - 4 ; * i -A * ' " ) ; . 



KLAPROTH'S analysis of this mineral approaches very closely 

 to mine. It is as follows : 



Silica, ...... 45 



Magnesia, ..... 24.75 



Alumina, ..... 9-25 



Peroxide of iron, ... 1.00 



Potash, . ..... 0.75 



Water, ...... 18.00 



98.75* 



If we calculate from the second of my specimens, which I 

 consider as the purest, the atomic constituents of soapstone are, 



25 atoms silica, 

 12 atoms magnesia, 

 5 atoms alumina, 

 atoms water. 



It is obvious, at first sight, that the atoms of silica are to 

 those of the two bases as 3 to 2. Hence it follows that soap- 

 stone is a compound of two sesquisilicates, namely of magnesia 



* Beitrage, v. 



