ANALYSIS OF MAGNESITE. 



277 



.1 



and dissolved gradually without effervescence in diluted sul- 

 phuric acid. 



c. The solution of experiment a was carefully evaporated, «Resicluum of 

 and half an ounce of concentrated muriatic acid added *^^ "?""*"'^ 

 with an equal quantity of water. This was boiled and fil- 

 tered. There remained 4*5 grs of an earth, which readily 

 dissolved in a caustic alkaline lixivium. This, witH"it3; In- T 

 solubility in acids, showed it to be silex, '^ ;■*>(*'* ^. 



d. The solution separated from the silex in the preceding The solution 

 experiment was supersaturated with ammonia, which ren- P''^^'f"?'*^'5l 

 dered it slightly turbid. After the precipitate had sub- * 

 sided, the fluid was poured off. The precipitate, well 



washed and dried, weighed half a grain, and consisted of 

 alumine, mixed with oxides of iron and manganese. 



e. The liquor of experiment d was decomposed at a boil- anddecom- 

 iag heat by carbonate of soda. The precipitate obtained, posed by car 

 after it had been washed and heated redhot, weighed 45*5 



o-rs. It was of a'brownish colour. On redissolving it in 

 sulphuric acid, a brown residuum remained, weighing half 

 a grain, and composed of the oxides of iron and manga- 

 nese. The sulphuric solution yielded sulphate of magnesia, 

 from which a quarter of a grain of sulphate of lime was 

 separated. 



Of this variety of magnesite therefore 100 parts contain 



Magnesia • 45'42 Component 



Carbonic acid 47 parts. 



Silex 4-50 



Water 2 



Alumine 0'50 



Oxides of iron and manganese • • 0*50 



Lime 0-08 



TOO. 



.ot'**«wTiAW<- vncffytla; K VllL 



