On the Oxide of Manganese of Nay gag. 325 



having discovered either gold or silver in it, as asserted by 

 M. Muller, of Rechenstein. ♦ 



The celebrated Berlin chemist having thus enriched mi- 

 neralogy with a new species ot the manganese genus, which 

 down to the present time had existed only in one form, that 

 of oxidated manganese, he has also thereby enriched che- 

 mistry with a new fact concerning the action of the nitric 

 acid upon sulphurets, for the decomposition of which it is 

 usually employed, with the view of dissolving the metallic 

 oxide combined with sulphur, without touching the latter. 



As soon as M. Haiiy recognized this mineral in his col- 

 lection, he sent us a specimen in order that we might sub- 

 mit it to analysis. 



M. Proust also analysed this mineral almost at the same 

 moment with M. Klaproih. The former observed the same 

 phaenomena, but for want of a large enough quantity he 

 was not able to determine the state in which manganese is 

 when combined with sulphur, nor the respective quantities 

 of these bodies. 



The sulphuret of manganese of naygag is accompanie4 

 with manganeseous carbonated lime: it has for a matrix 

 a white hyaline quartz : its specific gravity is 4 : its texture 

 is lamellous, with a metallic lustre, when the surface has 

 not been long exposed to the air. Reduced into powder, it 

 is of an olive green colour : it loses nothing by heat. 



Five grammes of this mineral, perfectly freed from its 

 matrix, were reduced to a very fine powder and treated with 

 weak nitric acid; which immediately exercised a lively action 

 upon it, accompanied with a disengagement of sulphuretted 

 hydrogengas. We gathered a certain quantity of this gas, in 

 order to examine its nature. The mixture was slightly 

 heated, and a new portion of the nitric acid was introduced 

 until effervescence ceased : the liquor was then filtered, which 

 was a little reddish, but became colourless upon the addition 

 of water. The residue weighed a decigranmie. It was com- 

 posed of blackish brown flakes, which, upon being exposed 

 to flame with the blowpipe, took fire like sulphur, spread a 

 slight arsenical smell, and left a substance which did not 

 colour borax like maniianese, but like iron. 



X :i The 



