

ON MANGANESE 91 



immediate objection ; which is, that the green colour in this 

 case should have been destroyed by the nitre still remaining. 

 I observed that such a green alkali fused with nitre did not, 

 however, lose its colour. When fixed alkali is made to run 

 over the crucible by a strong fire, the part that attaches 

 itself to the outside acquires a dark green colour, in con- 

 sequence of the ashes uniting with it. If one part of alkali 

 of tartar be mixed with one-fourth of fine sifted ashes, and 

 one-eighth of nitre, a dark green mass is obtained, which, 

 when dissolved in water, yields a beautiful green solution, 

 and, when filtered, turns red on adding a few drops of 

 vitriolic acid (Sec. xxxvm. (6), (c)). Some days afterwards I 

 found a brown powder precipitated, which, though in a small 

 quantity, appeared on experiment to be precisely the same 

 substance as manganese. 



A sufficient quantity of sifted ashes was dissolved in 

 muriatic acid in a sand-heat. During the digestion, the 

 same smell of aqua regia that arises from manganese and 

 muriatic acid was perceptible. Some hours after I mixed 

 a certain quantity of vitriolic acid with this solution, in 

 order to precipitate the greater part of the calcareous earth 

 that was present. The second day I filtered it, and what 

 passed through the filter had a yellow colour, and with 

 alkali of tartar afforded a yellowish precipitate. This 

 powder being edulcorated, dried, and calcined in the open 

 air upon an iron plate placed on burning charcoal, assumed 

 a dark grey colour. It should have been quite black like 

 manganese if an extraneous earth had not still been mixed 

 with it (Sec. xv. (c)). This calcined powder was not entirely 

 soluble in pure nitrous acid ; but on adding a little sugar 

 a clear solution was instantly procured. When mixed with 

 alkali it yielded a green mass before the blowpipe ; with 

 glass of borax it assumed a yellow colour. From this latter 



