OF ARTS AND SCIENCES. 187 



before. An analysis of the air-dried salt, and a determination of its 

 solubility, proved that the acid was identical with that made by the 

 action of bromine upon succinic or mucobromic acid. 



0.5225 grm. of the air-dried salt gave 0.2741 grm. BaSO^. 



Calculated for BaC«Br,04.2II,0. Found. 



Ba 30.78 30.84 



9.2092 grm. of an aqueous solution saturated at 18°. 5 according to 

 the method of V. Meyer, gave on evaporation with H^SO^ and ignition 

 0.2944 grm. BaSO,. 



According to this determination, an aqueous solution saturated at 

 18°. 5 contains 5.61 per cent of the anhydrous salt. 



This oxidation of mucobromic acid by means of argentic oxide 

 into dibrommaleic acid, 



C,H2BrA + = C,H,BrA, 



would seem to show conclusively that it is the half aldehyde of the 

 dibasic dibrommaleic acid. 



Decomposition by Heat. 



If mucobromic acid is quickly heated, the greater part of it distila 

 unchanged ; but, if the temperature is so regulated that it can distil 

 but slowly, a great part of it suffers decomposition. The reaction 

 which it undergoes I have, as yet, studied only so far as to prove that 

 dibrommaleic acid is one of the chief products. If the acid is mixed 

 with sand and slowly distilled, streams of hydrobromic acid and car- 

 bonic dioxide are given off, and a colorless oil passes over, which, on 

 standing, partially solidifies. On the addition of water, the solid por- 

 tion dissolves, leaving an oil which is volatile with steam, and is not 

 wholly insoluble in water. Its aqueous solution reduces argentic 

 oxide, and possesses an intolerably sharp, pungent odor. In the inves- 

 tigation of this oil, I have not yet obtained definite results. 



The aqueous solution contained dibrommaleic acid, which was 

 identified by an analysis of its barium salt. The solution of the barium 

 salt obtained, at first was highly colored, and from it pure material 

 could be made only by repeated precipitation from aqueous solution 

 with the smallest possible quantity of alcohol. In this way, a per- 

 fectly colorless salt was made, and it was then recrystallized from 

 water. 



0.6652 grm. of the air-dried salt gave 0.3498 grm. BaSO^. 



