vf the Oxides of Manganese. 169 



Red oxide 98.098 



Oxygen . v^rr ;> - J:ra 0'215 

 Water '-.-. -,'viifc 1, ^ - 0'435 

 Baryta . ;{ r ..- . >;; ,/ 0111 

 Silica 0-337 



100-000 



This oxide is manifestly an anhydrous red oxide of manga- 

 nese. The small quantity of oxygen lost at a white heat is pro- 

 bably owing to the admixture of a little deutoxide or peroxide, 

 combined with the baryta. 



From some preliminary experiments on Hausmannite M. 

 GMELIN of Heidelberg * inferred that it is a pretty pure red 

 oxide, an inference which entirely agrees with the result of the 

 preceding analysis. This is the only chemical examination of 

 Hausmannite by other chemists, which I have met with. The 

 material for my analysis was part of a specimen from Ihlefeld, 

 for which I am indebted to the kindness of Professor STRO- 

 MEYEB. 



Analysis of Pyrolusite, or the Prismatic Manganese-ore. 



The following analysis was made with a compact columnar 

 variety from Elgersburg, which has a specific gravity of 4*94, 

 and the individuals of which have a parallel direction. With 

 sulphuric acid it does not yield a trace of chlorine ; and the only 

 impurities which I could discover in it are silica and baryta, the 

 former amounting to 0'513, and the latter to 0*532 per cent. 



* LEONHARD'S Handbucfi der Oryktognosie. 

 VOL. XI. PART I. 



