46 SIDERITE. 



tube, the precipitate again mixed with water, and after 

 the clear liquid has been again decanted, quickly thrown 

 upon a filter, and rapidly washed, air being excluded, 

 with water which has been previously boiled and al- 

 lowed to cool. 



The iron precipitate is dissolved in dilute hydro- 

 chloric acid, the baryta separated by sulphuric acid, 

 and the sesquioxide of iron precipitated by ammonia. 



The solution, which contains the protoxide of iron, 

 is mixed with hydrochloric acid and chlorate of potas- 

 sa, and concentrated by evaporation; the baryta is then 

 precipitated by sulphuric acid, and afterwards the ses- 

 quioxide of iron by ammonia. 



25. SIDERITE. 



FeO, CO,,, frequentlv containing MnO, CO^ CaO, CO 2 , 

 "and MgO, CO 2 . 



I. The best method of analysis, which is especially 

 applicable where but little manganese is present, is the 

 following: A weighed portion of the powdered ore, 

 previously dried, is dissolved in hydrochloric acid, 

 with the aid of heat, nitrate or chlorate of potassa be- 

 ing added from time to time, so that the whole of the 

 protoxide of iron is sure to be converted into sesqui- 

 chloride. The solution, which must still be acid, so 

 that chloride of ammonium may be formed, is diluted, 

 and gradually neutralized with dilute ammonia, until 

 it has acquired a dark brown-red color, and a small 

 quantity of hydrated sesquioxide of iron is precipi- 

 tated. The whole of the sesquioxide of iron is then 

 separated by neutral succinate of ammonia, while prot- 

 oxide of manganese, lime, and magnesia remain in 

 solution. The precipitated succinate of sesquioxide of 

 iron is rapidly filtered off, washed with cold water, 



