ON MANGANESE 53 



another ounce of diluted acid of vitriol; which, however, 

 appearing to have no action upon it, I put another half 

 ounce of levigated manganese into the mixture, and boiled 

 it. The solution still retained some acid taste; but on 

 adding 2 drms. more of levigated manganese its taste grew 

 bitter. 



(c) I exposed I oz. of powdered manganese, mixed with 

 as much concentrated acid of vitriol as to reduce the mass 

 to the consistence of honey, in a glass retort to the fire, till 

 it became red hot, during which operation some vitriolic acid 

 mixed with water came over in the receiver. After breaking 

 the retort, the mass was found hard, white in the inside, and 

 red on the surface; it weighed 12 J drms. This mass was 

 reduced to powder, and distilled water poured upon it; in 

 consequence of which a great heat was generated, and a 

 great deal of it dissolved. The solution, after being filtered, 

 was edulcorated. Afterwards, when it was dry, it appeared 

 of a dark grey colour, and weighed 1 J drm. This residuum 

 was calcined in an open crucible with concentrated vitriolic 

 acid, till no more vapours arose ; then it was put into water, 

 when 1 drm. remained undissolved, which was again calcined 

 with concentrated vitriolic acid, and the undissolved residuum 

 was a white powder, weighing half a drachm, (d) This white 

 residuum was further insoluble in the vitriolic acid. During 

 its fusion with borax, it made an effervescence, and yielded 

 a transparent brown glass ; it likewise effervesced with fixed 

 alkali, changing into a brown mass, which yielded an hepatic 

 smell with acids, becoming, at the same time, a gelatinous 

 mass, (e) The solution of manganese obtained by calcination 

 was evaporated, and, in the first place, a few small crystals 

 were deposited, which were nothing but vitriolated lime 

 (selenite). Afterwards, some very fine large crystals, of an 

 oblique parallelepiped form, were deposited, which increased 



