382 Mr. Kane — Chemical Examination of a 



native arseniuret of manganese described by mineralogists, 

 therefore I resolved to more thoroughly investigate the subject ; 

 and after the most careful study of the nature of this sub- 

 stance which I was competent to effect, I can reconcile the 

 appearances which I observed, to no other supposition than 

 that which I before mentioned. 



External Characters. 



The specific gravity of a homogeneous fragment was found 

 to be 5.55. 



Hard, brittle, perpendicular fracture, uneven, fine-grained, 

 brilliant ; colour greyish white, growing dull, and becoming 

 covered with a fine blackish powder on exposure to the air ; 

 horizontal fracture, dull and mammillary. It is very easily 

 broken in this direction; in fact, the ore seems entirely com- 

 posed of a series of mammillary laminae. 



Before the blow-pipe, it burns with a bluish flame, and 

 emits a smell similar to that of arsenic, when heated strongly. 

 The greater part of the ore sublimes. Whilst the ore is burning, 

 it throws off white fumes which condense on the cold part of 

 the charcoal, under the form of a white powder. When a 

 platina stand was used, the mineral fused and united with it. 



This ore is totally dissolved by nitro-rnuriatic acid. 



When boiled in a large quantity of nitric acid it is entirely 

 dissolved ; but when the quantity of acid used is small, the 

 ore is converted into a white powder, soluble in more acid. 



When re-agents were applied to a solution of this mineral 

 in nitro-muriatic acid, the following effects were observed : — 



Alkalies precipitated it white, which gradually passed to 

 brown. 



Carbonated alkalies produced a precipitate; the colour of 

 which was more permanent. 



Lime-water and 



Solution of acetate of lime produced white precipitates, in a 

 portion of the solution which had been rendered neutral. An 

 excess of acid re-dissolved these precipitates. 



Tincture of galls did not affect it. 



