Seyhert'^s Analysis of the Maclureite. 337 



per se ; with borax it yields a transparent colourless and 

 vitreous globule. 



Analysis, (No. 1.) 



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

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

 platina crucible ; after the calcination, the colour of the 

 powder 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- 

 riatic acid, the acid readily acted on it, and converted it 

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

 which was treated with water acidulated with muriatic 

 acid, and again moderately evaporated; more water was 

 then added and the solution was tiltered, to separate the 

 silica, which, after edulcoration and calcination, weighed 

 0.91 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 in quantity, I supposed it to be a portion of 

 the silica adhering to the crucible, and therefore deemed 

 it unnecessary to examine it. 



C. After the separation of the silica, (B) the liquor was 

 neutralized with caustic potash •, it was then treated with the 

 hydro-sulphate of potash, which occasioned a black precipi- 

 tate ; this precipitate, after being wellwashed, was calcined 

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

 phur ; it was then treated with a little 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, and 

 thus proved to be peroxide of iron. 



D. The liquor (C) when tested with oxalate of potash, 

 gave 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, yielded 1.70 grammes of magnesia 

 on 3 grammes, or 56.666 per 100. 



