Bowen^s Analysis- of the Pyroxene. 345 



r 



€. The liquor (B) having been neutralized with am- 

 monia, was treated with the hydrosulphate of ammonia. 

 The black precipitate which was produced after being heat- 

 ed to expel the sulphur, and calcined with nitric acid, 

 weighed 4.192 grains. The aluraine separated in the usu- 

 al manner by the action of caustic potash, weighed 531 

 grains or 1,062 per 100. 



D. The metallic oxides, after the separation of the alu- 

 niine, weighed 3.645 grains. They were treated with mu- 

 riate of ammonia to which a small quantity of sugar had 

 been added, in order to separate the manganese. The per- 

 oxide of iron remaining, was equal to 3.004 grains of pro- 

 toxide in 50 grains, or to 6^008 grains per 100. The pro- 

 toxide of manganese amounted to .598 grains per 100. 



£♦ Oxalate of potash was then added to the liquor, 

 (D.) The precipitate of oxalate of lime when calcined 

 yielded 1 1,810 grains of lime, or 23.620 grains per 100. 



F. The magnesia was precipitated from the solution, 

 (E) by caustic potash at a boiling heat; when washed and 

 calcined, it weighed 07.250 grains or 14.500 per 100. 



The results of this analysis, give as the composition of 

 this mineral per 100 parts : 



A. Water . • . 00.468 containing oxygen. 



B. SiHca . . . 53.124 . . 26.72 



C. Alumina . . . 01.062 

 B. Protoxide of Iron • 06.008 . • 01.36 



D. Protoxide of Manganese 00.598 . . 



E. Lime . , . 23 620 . . 06.6 



F. Magnesia . . . 14.500 • . 05.81 



99.380 

 100.000 



OOO.G20 loss. 



Some mineralogists have considered this substance as 

 I^iallage. The preceding experiments, however, sufficient- 

 Jy prove that it is distinct from that mineral. In its exter- 

 nal characters, and also in its chemical composition, it^cor- 

 responds almost exactly with the Fyroxenie Sahlite of Swe- 

 den, It was discovered « number of years since by Pro- 



