184 PROCEEDINGS OP THE AMERICAN ACADEMY 



Calculated for BaC4Br204 . 2H2O. Found. 



Ba 30.78 30.69 



H2O 8.09 7.72 



The solubility was also determined by the method of V. Meyer. 



7.6833 grm. of the solution saturated at 19°.5 gave, on evaporation 

 with H2SO4 and ignition, 0.2446 grm. BaSO^. 



An aqueous solution saturated at 19°. 5 contained therefore 5.58 

 per cent of the anhydrous salt. 



This proves that dibrommaleic acid may be carried unchanged 

 through its anhydride, and that it consequently belongs to the maleic 

 series, unless, indeed, its behavior is radically changed by the com- 

 plete replacement of its hydrogen by bromine. That such is not the 

 case lias recently been shown by Bandrowski,* who has discovered 

 an acid of the same composition, which is undoubtedly dibromfumai'ic 

 acid. This acid melts at 219-220°, and by distillation is converted 

 into dibrommaleic acid. 



Mucohromic Acid with Oxidizing Agents. 



The close connection between mucobromic acid and dibrommaleic, 

 as shown by its behavior when heated with bromine, naturally sug- 

 gested the direct conversion of the one into the other by oxidation. 



An aqueous solution of chromic acid does not act upon mucobromic 

 acid at ordinary temperatures, even after standing for weeks. On 

 warming, carbonic acid is freely given oflf, and at the same time a 

 sharp, acrolein-like odor is noticed. If one atom of oxygen is employed 

 for every molecule of mucobromic acid, a portion of the mucobromic 

 acid seems to be completely destroyed, while nearly one half of it 

 remains unaltered, and may be extracted with ether after the reaction 

 is completed. When two atoms of oxygen are taken, but little muco- 

 bromic acid escapes oxidation ; but I have been unable to isolate 

 well-marked products of the reaction, in any considerable quantities. 

 When the solution is distilled, the substance possessing the sharp, 

 pungent odor passes over with the steam. It is quite soluble in water, 

 although not in all proportions, and its aqueous solution reduces 

 silver energetically from the oxide even in the cold. Although this is 

 the most striking product of the oxidation, it is formed in such small 

 quantities that I have as yet been unable to study it further. After 



* Berichte der dcutsch. chem. Gesellscli., xii. 2213. 



