384 DR T. THOMSON on Asbestus, Chlorite, and Talc, 

 I found its constituents to be, 



Silica, 46.40 



Alumina, . . . . . 52.92 



99.32 



So that it is a simple anhydrous silicate of alumina. The 

 Cornish specimen differs from bucholzite, in containing water, 

 and in being contaminated with a little bisilicates of lime, mag- 

 nesia, and iron. Its lower specific gravity and inferior hardness 

 are probably owing to the presence of water. We may dis- 

 tinguish it by the name of Hydrous Silicate of Alumina, or Gil- 

 bertite. 



IV. SOAPSTONE. 



The mineral called Soapstone or Rocksoap, occurs in the Pe- 

 ninsula of the Lizzard, partly in a vein in serpentine at the 

 Lizzard Point, and partly near Mullyan Churchtown. The co- 

 lour is greenish-white, or almost white, often mottled with green 

 and red. The white portion often traverses the red in a kind 

 of irregular veins. When first extracted from the vein, it is soft, 

 but when left exposed to the air, it loses part of its moisture ; 

 becomes translucent on the edges, and harder ; though it is still 

 soft enough to be scratched by the nail. 



Feel unctuous or soapy ; lustre resinous. 



Sectile : opaque, or nearly translucent on the edges. 



I found the specific gravity of a white specimen 2.396 : of a 

 red specimen 2.411. Both of them had been about sixteen 

 years in my cabinet. 



The following table exhibits the constituents of these two 

 specimens. The first was mottled red and white, the second 

 was white, and consequently purest : 



