ANALYSIS ON SOiJALITff. g89 



Brittle. 



Easily frangible. 



Specific (gravity, at the temperature of 60°, 2*378. The 

 Bpecimen vvns not absolutely free from sahlite; 



When heated to redness, does not decrepitate, nor fall to 

 powder, but becomes dark gray, nnd assumes very nearly the 

 appearance of the Swedish riatrolite of Mr. Allan, which I 

 consider as fettsteiu. If any particles of sahlite be mixed 

 with it, they become very conspicuous, by acquiring a white 

 colour, and the opacity and appearance of chalk. The loss 

 of weight was 2*1 per cent. I was not able to melt it before ^ 



the blow-|;)ipe. 



1. A hundred grains of the mineral, reduced to a fine Chemical ana- 

 powder, were mixed with 200 grains of pure soda, and ex- ^*^^* 

 posed for an hour to a strong red heat, in a platinum cruci- 

 ble. The mixture melted, and assumed, when cold, a beau- 

 tiful grass-green colour. When softened with water, the 



portion adhering to the sides of the crucible acquired a fine 

 brownish-yellow. Nitric acid being poured upon it, a coo;- 

 plete solution was obtained. '>i;? v 



2. Suspecling, fkoni the appearance which the fused mflss 

 assumed, that it might coniain chromium, I neutralised the 

 solution, as nearly as possible, with ammonia, and then 

 poured into it a recently prepared nitrate of mercury* A 

 white precipitate fell, which being dried, and exposed to a 

 heat rather under redness, was all dissipated, except a small 

 portion of gray matter, not weighing quite 0*1 grain. This 

 matter was insoluble in acids, but became white. With pot- 

 ash it fused into a colourless glass. Hence I consider it as Siiexo 

 feilica. This experiment shows, that no chromium wad pre- 

 sent. I was at a loss to account for the precipitate thrown 

 down by the nitrate of mercury. But Mr. Allan having 

 shown me a letter from Ekeberg, in which he frefitions, that 



he had detected muriatic acid in sodalite, it wp.s easy to see 

 thftt the white precipitate was calomel. The v/hite powder 

 weighed 9,6 grains, indicating, according to the analysis of 

 Chenevix, about three grains of muriatic acid. Muriatic aci<l. 



3. The solution, thus freed from muriatic acid, being silex. 

 concentrated by evaporation, gelatinised. It was evaporated 

 nearly to dryness; the dry mass digested in hot water aci- 



VoL, XXIX.— August, 18U. C dulated 



