Seyhert^s Analysis of the Maclureite. 337 



perse; wifh borax it yields a fran.^parent colourless and 



Viiroous "lobule. 



Analysis^ (No. 1.) 



r 



A. Three grammes of the pure mineral, in the state of 

 un impalpable powder, were exposed to a red heat, in a 

 platina crucible ; after the calcination, the colour of the 

 ponder had become a shade darker, and it weighed 2.97 

 grammes, therefore the moisture, dissipated by calcina- 

 tion, amounts to 0.03 grammes on three grammes, or one 

 per one hundred. 



B. The calcined mineral (A) was boiled with nitro mu- 

 natic acid, the acid readily' acted on it, and converted it 

 info a jelly ; the mixture was evaporated to a dry mass, 

 Hhich Was treated with water acidulated with muriatic 

 acid, and again moderately evaporated; more water was 

 then added and the solution was filtered, to separate the 

 silica, which, after edulcoration and calcination, weighed 

 0.9] grammes, on 3 grammes, equivalent to 30.333 per 100. 

 At the close of the calcination, I observed that the upper 

 surface of the crucible was coated with a very minute por- 

 tion of a white sublimate, but as the matter was very in- 

 considerable m quantity, I supposed it to be a portion of 

 the silica adhering to the crucible, and therefore deemed 

 it unnecessar} to examine it. 



C After the separation of the silica, (B) the liquor wa^ 

 iieutralized with caustic potash; it was then treated with the 

 hydro sulphate of pota^h, which occasioned a black precipi- 

 tate ; this precipitate, after being well washed, was calcined 

 "n a porcelain vessel, to expel the greater part of the sul- 

 phur; it was then treated with alittle nitric acid and exposed 

 to a strong red heat,in a platina crucible; after this calcina- 

 tion it weighed 0.03 grammes on 3 grammes, or 1.666 per 

 100; this product, on examination with caustic potash, 

 Was found to contain neither manganese nor alumina, ajid 

 thus proved to be peroxide of iron. 



I^- The liquor (C) when tested with oxalate of potash, 

 g^ve no trace of lime* 



E. The liquor (C) treated with an excess of caustic pot- 

 ash, gave an abundant flocculent precipitate, which, on ex- 

 posure to a strong heat, >ie!ded 1.70 grammes of magnesia 

 on 3 grammes, or°56.666 per lOO. 



