m 

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



8. Nemalite of NUT ALL. 



For the specimen of this mineral which I subjected to ana- 

 lysis, I am indebted to the kindness of Professor NUT ALL. It 

 occurs in veins in the serpentine rocks of Hoboken, New Jersey, 

 and had always been taken for a variety of amianthus, till its 

 real nature was determined by Mr NUTALL *. 



Its colour is white, with a slight shade of yellow, or some- 

 times of blue. It is composed of long straight fibres, easily se- 

 parable, and bearing a close resemblance to asbestus. 



Soft enough to be scratched by the nail of the finger. 



Specific gravity 2.353. 



Opaque, or only slightly translucent. 



When exposed to a red heat it assumes a brown colour, re- 

 tains its fibrous texture, but becomes friable, and easily reducible 

 to powder. By this treatment it loses 29-66 per cent, of its 

 weight. The matter driven off is pure water. 



It dissolves in nitric acid, without effervescence, leaving be- 

 hind a little silica. 



By a careful analysis I found its constituents as follows : 



Magnesia, . . . . . 51.721 



Silica, D.-Htaifc !<-. i : . 12 - 568 

 Peroxide of iron, .;./..- ,,> -j 5.874 

 Water, 29.666 



99.829 

 This is equivalent to 



104 atoms water, 

 25 atoms silica, 



4 atoms peroxide of iron, 

 83 atoms magnesia. 



* See SILLIMAN'S Journal, iv. 19- 



