Examination of the Peroxide of Manganese. 87 



Bitartrate of potassa, particularly if warm, dissolv^es the deut- 

 oxide of manganese with considerable energy, at the same time 

 evolving oxygen and forming a tartrate of manganese and potassa, 

 which is a highly crystalline brownish mass, of hardly any flavor, 

 and solable both in nitric and hydrochloric acids. 



Benzoic acid. — When benzoic acid is boiled with peroxide of 

 manganese, there is a benzoate formed, slightly soluble in water. 

 Thus obtained, it is a dirty white substance, of a crystalline ap- 

 pearance. 



Succinic acid. — This acid forms a protosuccinate when di- 

 gested upon peroxide, but with the deutoxide, it, like tartaric 

 acid, forms a per-salt, which is soluble in water, of a whitish 

 color, crystalline and very acid. 



Racemic acid. — This like the last forms a per-salt with the 

 deutoxide, and a proto-salt with the peroxide. The resulting so- 

 lution, by evaporation, leaves the salt somewhat crystalline, 

 whitish brown, and quite acid. 



Citric acid. — With citric acid, both the per and deutoxide act 

 as towards the last. The percitrate obtained from the deutoxide 

 is a brown, gummy, seemingly uncrystallizable mass, of a pleas- 

 ant acid taste, slightly deliquescent, and is soluble, although not 

 very readily, in both nitric and muriatic acids. 



Gallic acid. — The pergallate of manganese may be obtained 

 by dissolving the peroxide in gallic acid. The solution thus ob- 

 tained is of a deep brown color, and the salt obtained by evapora- 

 tion is nearly black. It does not appear to crystallize. 



These are all the acids, of which I have been able to note the 

 action with the per or deutoxide of manganese. I have followed 

 Berzelius in calling peroxide, that one which might perhaps be 

 more correctly termed sesquioxide, as its formula'is Mn, but as it is 

 very similar to the analogous oxide of iron, also termed peroxide, 

 and as it is the highest oxide of manganese which forms combi- 

 nations with acids, it seems best to apply the term of peroxide to 

 this, and super or binoxide to the black oxide of commerce. 



If time should favor me, I propose to pursue the above subject, 

 as it is probable that much remains to be determined, concerning 

 the compounds of manganese, before we can say with propriety 

 that we are acquainted with the metal. 



Philadelphia, May 8th, 1841. 



