I'M) ANALYSIS o* 



weight amounts to 0. 03 grammes ; but as the Deut- 

 oxide of Iron, contained in the mineral must have 

 absorbed 0. 008 grammes of oxygen, in passing to 

 the state of peroxide, the loss due to water, there- 

 fore, amounts to 0. 038 grammes on 3 grammes, or 

 1.266 per 100. 



B. The calcined mineral (A.) was heated to red- 

 ness in a silver crucible, during 30 minutes, with 9 

 grammes of caustic potash ; the mixture on cooling 

 assumed a pale green colour ; it was treated with wa- 

 ter, to which it likewise communicated a greenish 

 hue ; this indicated a trace of manganese. Muriatic 

 acid, in excess, was added to it, the solution was 

 complete and of a yellow colour $ it was then evapo- 

 rated to a dry gelatinous mass, then treated with 

 water, acidulated with muriatic acid, and again mo- 

 derately evaporated ; more water was then added, 

 and it was filtered ; on the filter there remained Si- 

 lex* which, after being washed and calcined, weigh- 

 ed 1. 565 grammes on 3 grammes, or 52. 166 per 100. 



C. The filtered liquor (B.) was neutralized with 

 caustic potish, when treated with the hydro-sulphate 

 of potash, it yielded a black precipitate ; this precip- 

 itate was well washed and calcined, in a porcelain 

 vessel, to expel the greater part of the sulphur: 

 it was then treated with a small portion of nitric 

 acid, and exposed to a strong red heat, in a platina 

 crucible. The Alumine and peroxide of iron, thus 

 obtained, weighed 0.45 grammes; they were treated 

 repeatedly with caustic potash, until the Alumine 

 was completely separated, the per-oxide of iron then 



