1815.] in the Physical Sciences. 4* 



Black oxide of manganese . . . 52*60 



Silica 39-GO 



Oxide of iron 4*60 



Lime 1*50 



Water 2'75 



101-25 



The excess of weight was owing to the manganese in the orft 

 containing less oxygen than the black oxide, in which state it 

 was obtained by analysis. 



17. Sodalite, — Ekeberg analysed a mineral from Hefselkulla, in 

 the province of Nerike, in Sweden, which, from liis description of 

 it, seems to have some resemblance to sodalite ; but its constituents 

 differ materially. It occurs in an iron-mine mixed with quartz. Its 

 colour is greenish-grey ; lustre, pearly and inconsiderable ; prin- 

 cipal fracture foliated with a two-fold cleavage ; cross fracture gra- 

 nular, uneven ; translucent on the edges ; it scratches glass, but is 

 scratched by steel ; difficultly frangible; specific gravity 2'746. Its 

 constituents were, 



Silica 46 



Alumina 28-75 



Magnesia -, 13'50 



Oxide of iron 0-75 



Water 2-25 



Soda 5-25 



I>oss 3-50 



100-00 



18. Black Ganiet. — A specimen of black garnet from the iron- 

 mine of Svapj)avara, in Torneo Lappmark, analysed l)y Hisinger, 

 ;fave the following constituents : — • 



Silica 34-53 



Lime .• 24-36 



Alumina I'OO 



Oxide of iron \ . . . 36-05 



Volatile matter 0-50 



Loss ' 'i'SQ 



100-00 



19. Sparry Iron Ore. — A specimen of this mineral, from Rid- 

 darhyttan, in Wcrmeland, in Sweden, analysed by Hisinger, was 

 composed of 



Mod oxide of iron 63-25 



Oxide of manganese 3-00 



Lime ". 1-00 



Carbonic acid 30-00 



Water 1-75 



99-00 

 Vol.. V. N° I. \) 



