ANALYSIS OF IRON SPAR. g|5 



White iron spar. 



Iron, at a miuiiimia 25 ajid of white 



Carbonic acid united with the iron • • (i-s irouapar. 



Carbonaie of lime 43 



Water olcrystailization 17'2 



Pyrites...... ..... 3 



100 



After the publiralion of Mr. Drappier on the same sub- ^J" Drappier's 

 ject, whose results were so different from mine, I examined ferent!^'^'^^ 

 anew the pi-odtKis, which I had carefully preserved: ^nd ^^^ , 



accordingly I treated the 48 parts of carbonate of lime, bonate uf iim* 

 found in the white iron spar, with weak sulphuric acid. ^<^^''^^i'^. 

 very brisk effervescence took place, and a very bulky ujag- 

 nia was formed, which had ail tne characters of sulphate of 

 lime. This matter, having been heated with the usual pi-e- 

 cautions to expel the nioisiu.e, was sli-^'litiy calcined to drive 7 parts ofitnot 

 pif the excess of acid; diluted with a very small quaiitity fi"i'?> 

 of water; and filtered. 'J he liquor haa a bitter taste simi- 

 lar to that of sulphate of magnesia, bat slightly uietallic. 

 The rejoiduurn, teparated from the filter, and caiciucd, was 

 perfectly white a^d insipid. It weighed 37 parts, if we 

 admit 32 parts of lime in 100 of crystallized sulphate, there 

 will he i23 in the 57 calcined : and if there be 44 parts of 

 carbonic acid jn 100 of carbonate, there must have been 

 only 41 per cent of carbonate of lime, instead of 48 per 

 cent mentioned above. 



The liquor mentioned above was left to evaporate slowly 

 in the open air. After a few days the whole was crystallized 

 into a white salt, that weighed 26 parts. The solution of 

 this salt in water was very bitter, and still retained its metal- 

 lic taste. On caustic potash being added, a bulky white 

 precipitate was formed, v.hich had the appearance of mag- 

 nesia. When separated, dried, and calcined, it was of a but carlion:!!© 

 light violet colour, owing to the presence of oxide of man- °^ ""£"*^*'^ 

 gane^e, and weighed 5 parts. These being added to the 41 

 of carbonate of lime give but 2 of loss, which may be as- 

 cribed to carbonic acid belonging to the magnesia. Thus 

 we must admit 7 P^'' cent of carbonate of magnesia, the 

 quantity of manganese being but very small. 



The ma^^esia coloured with manganese was treated with ^^^^^ ^ minute 



radical 



