Chap. 22.] Manganefe found in Vegetables. 129 



m moift weather, it foon crumbles into a blackifh brown 

 powder, which is fomewhat heavier than the regulus 

 from which it was produced. 



The calces of manganefe retain their oxygen fo 

 weakly, that part of it may be expelled by the appli- 

 cation of a ftrong heat. They alfo part with their 

 oxygen to unctuous oils. If half a pound of that ore 

 of manganefe called black wad is well dried before the 

 fire, afterwards fufFered to cool for about an hour, and 

 then mixed with two ounces of linfeed-oil, fmall clots 

 will be formed, and in little more than half an hour 

 the whole will gradually grow hot, and at laft burfl 

 into flame. 



Manganefe feems to be contained in the afhes of 

 molt vegetables, and to it the blue or greenim colour 

 of calcined vegetable alkali is owing. If three parts 

 of alkali of tartar, one of fifted ames, and one-third of 

 nitre, are melted together, they form a dark green mafs, 

 which being diflblved in water, affords a beautiful green 

 folution j this being filtered on the addition of a few 

 drops of vitriolic acid becomes red, and after a few 

 days a brown powder is feparated, which has all the 

 properties of manganefe. 



The vitriolic, nitrous, and marine acids diflblve the 

 regulus of manganefe in the ufual ways. The black 

 calx is nearly infoluble. in the acids, unlefs it is deprived 

 of part of its oxygen by the addition of fome inflam- 

 mable or metallic fubilance. The marine acid, how- 

 ever, digefted with the black calx of manganefe, dif- 

 folves it without addition, in proportion as it lofes fome 

 part of its oxygen. The oxygen uniting with part of 

 the muriatic acid, renders it volatile, and converts it 

 into oxygenated muriatic acid. The permanent fo- 

 lubility of the black calx of manganefe in the acids, 

 depends on the acid, or fome fubftance mixed with the 



VOL. II. K acid, 



