1 88 Dr. Walchner's Mineralogicul and Chemical 



100 parts of this mineral therefore contain 



Silica '. 31-634 



Protoxide of iron .... 29*711 



Magnesia 32-403 



Alumina 2-211 



Oxide of manganese . . . 0-480 



Potassa 2-788 



Traces of chrome * 



99-227 

 § 11. 

 Through the kindness of my honoured teachers MM. Haus- 

 mann and Stromeyer of Gottingen, I was enabled to submit 

 to a chemical analysis some slags, the mineralogical similarity 

 of which with our mineral has been mentioned above. The 

 same method was followed in the analysis which was observed 

 in that of the hyalosiderite, and I therefore briefly state the 

 results. 



§ 12. 



An iron slag from the iron smelting works near Dax in 



the Pyrenees, which M. Hausmann has described f, and 



which M. Stromeyer kindly presented to me, had the specific 



gravity of 3-700 at the temperature of 73-4 F. and contained, 



in 100 parts, Silica 32*959 



Protoxide of iron . . 61-235 



Magnesia 1.896 



Alumina 1-560 



Oxide of manganese . . 1*301 



Potassa 0*204 



99*155 

 § 13. 

 Another iron slag, from Bodenhausen in the Hartz, which 

 in its external appearance bore the greatest resemblance to 

 our mineral, was kindly presented to me by M. Hausmann. 

 Its specific gravity was 3'529 at the temperature of 70*7 F. 

 and it contained, 



Silica 32*346 



Protoxide of iron . . 62*042 

 Magnesia .... 1*404 

 Oxide of manganese . 2*645 



Potassa 0*285 



99*746 

 * My honoured friend Professor Buzengeiger directed my attention to 

 the presence of chrorre in this mineral. Chrome has probably been over- 

 looked in many minerals. On a future opportunity I shall have occasion 

 to point out its existence in a mineral long known and frequently analysed, 

 f Moll's Ephemerides, d. B. u. H. III. 1815, p. 39. ff. 



A third 



