48 SIDERITE. 



is gradually mixed with carbonate of baryta, which 

 precipitates the sesquioxide of iron only. When a 

 slight excess of carbonate of baryta has been added, 

 and the solution well stirred, it is filtered. The washed 

 precipitate is dissolved in dilute hydrochloric acid, the 

 baryta precipitated by sulphuric acid, and the sesqui- 

 oxide of iron by ammonia. 



From the solution which contains the other three 

 bases, the dissolved baryta is first precipitated by sul- 

 phuric acid, and the solution treated as in No. 12. 



IV. The diluted solution, obtained as in I, is neu- 

 tralized with carbonate of soda till it has a dark brown- 

 red color, mixed with a saturated solution of acetate of 

 soda, and chlorine gas passed into it which precipitates 

 the manganese, or it is heated to ebullition, when the 

 whole of the sesquioxide of iron is precipitated. 



The filtrate is neutralized with carbonate of soda, 

 mixed with hypochlorite of soda (containing bicarbo- 

 nate of soda), and allowed to stand in a closed vessel 

 for twenty-four hours, when the manganese is precipi- 

 tated as hydrated sesquioxide, which is ignited and 

 weighed as proto-sesquioxide. 



From the filtered liquid the lime and magnesia are 

 separated as above. 



V. The solution of oxide of iron is precipitated by 

 ammonia, the liquid boiled as long as ammonia is given 

 off, and the oxide of iron filtered off, which is now free 

 from lime, magnesia, and manganese. It may be fil- 

 tered with free access of air, for the fluid contains no 

 free ammonia. The solution is concentrated by evapo- 

 ration and the three bases precipitated by an excess of 

 carbonate of potassa, and boiled until ammonia ceases 

 to be disengaged. 



It is then filtered, the precipitate dissolved in nitric 

 acid, evaporated to dry ness, and the saline mass care- 

 fully raised to a dull red heat. The lime and mag- 



