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III. Chemical Analysis of a Specimen of Magnetic 

 Iron-Ore from Greenland. 



By Thomas Thomson, M. D. F. R. S. L. & E. 



{Feadgtk March 1811.) 



As iron is scattered over the surface of the earth 

 in greater profusion than any other metal, and as 

 it is very easily acted upon and altered by the ac- 

 tion of the air, of water, and of a variety of other 

 agents, we need not be surprised that the number 

 of its ores is very considerable. It is from these 

 ores that the metal is extracted ; and it has been 

 observed, that the quality of the iron obtained, 

 very much depends upon the nature of the ore 

 which has been employed in the manufacture. 

 Some varieties of iron are much brittler, much 

 weaker, much tougher, much more ductile, &c. 

 than others. These differences undoubtedly de- 

 pend upon the foreign substances which happen 



