3S2 Examination of Ores of Iron. 



(1.) One hundred grains lost in calcining one grain in 

 weight. 



Analysis. (2.) The remaining ninety-nine grains were sub- 

 mitted to muriatic acid in the usual way, which dissolved the 

 oxide of iron, leaving seven grains not acted upon. The 

 seven grains appeared to be sand composed of fragments of 

 granite. Felspar, quartz, and mica, were easily distinguished 

 by the microscope after the oxide of iron had been removed. 



(3.) The solution of (2,) containing the muriate of iron, 

 was now precipitated with pure potash and filtered. The 

 oxide of iron caught on the filter, was washed, dried, and 

 then ignited with wax, it then weighed ninety-one grains. 



(4.) Ten and a half grains of the oxide were dissolved in 

 muriatic acid, and neutralized with water of ammonia, and 

 precipitated with benzoate of ammonia, and filtered ; the fil- 

 tered solution was then boiled to dryness; the dry mass was 

 then sublimed to get clear of the muriate of ammonia ; there 

 remained in the subliming vessel, of manganese. 25 of a grain. 

 Now if 10.50 gives 25, 91 will give 2.87. 



(5.) The seven grains of earthy admixture was then powder- 

 ed and fused with pure potassa, which dissolved all but a 

 trace. 



Hence this ore is composed of 

 Black oxide of iron, - 

 Manganese, - 



Silicious admixture, - 



Or of oxygen, 



Iron, -..-•- 

 Manganese, 

 Silicious admixture, 



