176 Contributions towards [Sept, 



III. Properties of Metallic Manganese. 



It has a silver white colour inclining to grey ; the colour of 

 brittle cast-iron. In the open air it emits a peculiar smell, not 

 very unlike that of rancid fat. 



Its lustre is not remarkably great. 



Its fracture is uneven, and very fine granular. 



It is not so hard as cast-iron, and easily yields to the file. 



In point of brittleness it approaches cast-iron. 



Mr. G. O. B. R. Karsten and myself found its specific 

 gravity 8 "01 3. 



It is not attracted by the magnet; but a very small quantity of 

 iron renders it magnetic. 



When the metal is completely free from iron and copper it 

 changes instantly in the air, and therefore cannot be preserved. 

 It becomes immediately yellow and violet, and speedily crumbles 

 into a light brown powder, which soon becomes darker. Even 

 in alcohol, in which I have attempted to preserve it, the pure 

 metal speedily crumbles down to powder. This unpleasant expe- 

 riment I have made more than once to my sorrow. 



It is best preserved in a vessel completely filled with quick- 

 silver, and covered over with another vessel. It appears, how- 

 ever, that the metal, through length of time, amalgamates with 

 the quicksilver, especially when it is only in small quantity ; at 

 least the quicksilver acquires a very thick firm skin. I shall ex- 

 amine this subject more accurately hereafter. 



It seems not improper to say a few words in this place about 

 native manganese, said to have been found by some mineral- 

 ogists. Picot la Peyrouse, in the Memoires de Toulouse, t. i. 

 p. 256, says, that he found it on the mountain Rancie, in the 

 valley of Viederose, not far from the village of Sem, in the 

 cidevant county of Foix. Most mineralogists and chemists have 

 combated his assertion, and have grounded their opinion upon 

 the rapidity with which artificially prepared manganese alters 

 when exposed to the air. I am, however, of opinion, that 

 manganese may exist native provided it be in combination with 

 other metals; for I found that when during my experiments a 

 portion of iron (derived from the pitcoal with which I sometimes 

 filled up the crucible) had united itself with the reduced manga- 

 nese, in such cases the resulting regulus was not altered by ex- 

 posure to the air, and might be kept in an open vessel without 

 undergoing any farther change. In this state it possessed a small 

 degree of malleability, and was attracted by the magnet. 



If the pure manganese be left for some days in contact with 

 the charcoal, it attracts the oxygen of the charcoal (?), and falls 

 down in the state of a brown powder. This ready oxydation at 



