378 PROCEEDINGS OF THE AMERICAN ACADEMY 



H 



c 



H 



The barium salt was also made by neutralizing the acid distillate 

 with baric carbonate. The salt obtained on evaporation was either 

 recrystallized from water, or precipitated from a concentrated aqueous 

 solution by alcohol. I failed to find any definite statements as to the 

 composition of the salt thus precipitated by alcohol, but experiments 

 of my own showed that it contained one molecule of water like the salt 

 crystallized from water. 



I. 1.1456 grm. of the air-dried salt lost at 150° 0.0780 grm. H 2 0. 



II. 0.9187 grm. of the air-dried salt lost at 125° 0.0609 grm. H 2 0. 



III. 0.4561 grm. of the air-dried salt gave 0.3899 grm. BaS0 4 . 



IV. 0.6868 grm. of the air-dried salt gave 0.5841 grm. BaS0 4 . 



Calculated for Found. 



Ba(C 2 H 3 2 ) 2 . H 2 0. I. II. IH. IV. 



H 2 6.59 6.80 6.62 



Ba 50.18 50.25 50.02 



0.8554 grm. of the salt dried at 125° gave 0.7811 grm. BaS0 4 . 



Calculated for 

 Ba^HA)* Found. 



Ba 53.73 53.69 



It thus appears that acetic acid is formed in the decomposition of 

 argentic dibrommaleate by water at 150° and the reaction may be 

 expressed by the equation : 



Ag 2 C 4 Br 2 4 + 2 H 2 = 2 AgBr + C0 2 + C 2 H 4 2 . 



The weight of baric acetate which was obtained from the distilled 

 liquid amounted to about 60 per cent of the theoretical yield required 

 by this equation, while 85 per cent of the theoretical amount of free 

 acid, calculated as acetic acid, was found by direct titration of the con- 

 tents of the tubes. The higher result in the latter case may in part 

 have been due to incomplete expulsion of the carbonic dioxide, but the 

 most careful search failed to show that any well defined organic acid 

 except acetic acid had been formed in the reaction. Dibrommaleic 

 acid therefore yields, under the conditions prescribed by Bourgoin for 

 its conversion into dioxymaleic acid, carbonic dioxide and acetic acid. 

 The facts observed give no certain information as to the mechanism 

 of the reaction. If it is assumed that the body 



