132 The neiv Mineral Newboldite. [Nov. 



a flaky white residuum which coagulates into a soft globule floating on 

 the solution, which is pure sulphur. 



If the boiling is gentle the sulphur is obtained in a light flake. 



The solution of the pure mineral in nitro-hydrochloric acid when 

 filtered from the sulphur is of a pale gold colour. When evaporated 

 it crystallised largely in minute silky needles, which appear in mamil- 

 lated or concretionary heaps if the evaporation is slow. They are ap- 

 parently insoluble in water, and in the mouth, with a slight astringency, 

 (probably from the muriate of iron) they are tasteless and lumpy like 

 argillaceous earth, though without any decided taste except an earthy 

 one. The muriate of iron gelatinises amongst them. The concretions 

 are soluble in nitric acid. At a red heat on platina they become dull 

 but do not otherwise alter. 



To re-agents the solution gives as follows : — To Sulphide Ammonium 

 a dirty greenish- brown precipitate with black grains, which becomes 

 of a sooty black, soluble in muriatic acid. 



Yellow Prussiate of Potass very pale bluish white. 



Caustic Potass very pale amber-white precipitate, plentiful. 



Carbonate Potass, as Potass, but partly soluble in Ammonia. 



Ammonia. — Sparingly, the reddish precipitate of iron ; and a white 

 precipitate with excess. 



Tinct : galls. — Brown colour, but no precipitate. 



Oxalic Acid. — A precipitate, soluble when ammonia is added. 



Phosphate Soda. — White precipitate soluble in ammonia and in 

 acids. Re appears with Potass. 



Cyanide of Potassium. — A dirty amber-coloured precipitate. 



By Wollaston's process (Carbonate of Ammonia and phosphate of 

 Soda.) — A plentiful precipitate, like that of the Phosphate of Magnesia 

 is obtained. 



Analysis. 



I have already adverted to the extreme difficulty of obtaining any 

 portion of the mineral pure enough for an analysis. The process 

 adopted was to pulverise the mineral and, 



1. Dissolve it in nitro-hydrochloric acid, at a boiling heat. 



2. Filter to separate the sulphur and silex. 



3. Burn off the sulphur from the silex. 



4. Precipitate the sulphuric acid formed in the solution by nitrate 



