Iron. 277 



SPECIES XII. 



Red Calx of Iron united to Siderite. 

 Grey Iron Ore. 



17. This has a fhining metallic appearance* 

 and commonly gives fire with fteel ; it is not 

 in the leaft magnetic, and when fcratched 

 fhews a red trace ; it yields from 40 to 66 

 per cent, of coldjhort iron. 



1 8. The ore called by the Swedes fmjlierne 

 malm, or miner a fleiadum, is a mixture of 

 the grey iron ore, with rhombic nodules of 

 that delcribed in N- 5. 



SPECIES XIIL 

 Argillaceous Iron Ores. 



19. Of thefe we may diftinguifh two prin- 

 cipal varieties, namely, thofe found in 

 mountains and high lands, and thofe found 

 in fwampy grounds, or low lands overflown 

 with water ; both are deftitute of metallic 

 luftre, but very weighty, and fome of them 

 when dry abforb water like clays. 



Tj I. VARIETY. 



