212 PROCEEDINGS OP THE AMERICAN ACADEMY 



The solubility of the acid in water at ordinary temperatures we 

 determined by neutralizing with baric carbonate the solution made 

 according to V. Meyer's method, a-nd evaporating the filtered solution 

 with sulphuric acid. 



I. 12.5364 grm. of a solution, saturated at 20°, gave 0.2070 grm. 



BaSO,. 

 11. 11.6241 grm. of a solution, saturated at 20^^, gave 0.1712 grm. 

 BaSO,. 



III. 8.4358 grm. of a solution, saturated at 20°, gave 0.1248 grm. 



BaSO,. 



IV. 10.6740 grm. of a solution, saturated at 20°, gave 0.1581 grm. 



BaSO^. 



As the result of these determinations, we find that an aqueous solu- 

 tion of the acid saturated at 20° contains the following percentages : — 



I. n. ni. rv. 



3.16 2.91 2.92 2.93 



Fittig and Petri found that the dibromacrylic acid made from tri- 

 bromsuccinic gave at 20° a solution which contained 3.355 per cent 

 of the acid. 



Baric Dibromacrylate, Ba(CgHBr202)2-2H20. An aqueous solution 

 of the acid was neutralized with baric carbonate, and the filtered solu- 

 tion evaporated on the water bath. On cooling, the barium salt crys- 

 tallized in rectangular plates, whose angles were, however, often more 

 or less modified. 



The air-dried salt lost, on heating to 100°, two molecules of water. 



I. 0.4018 grm. of air-dried salt lost at 100° 0.0226 grm. H.O. 

 11. 0.4644 grm. of air-dried salt lost at 100° 0.0261 grm. H^O. 

 in. 0.5086 grm. of air-dried salt lost at 100° 0.0299 grm. H2O. 



Calculated for Ba (C3HBr202)2.2H20. Found. 



I. II. in. 



H.O 5.71 5.62 5.62 5.88 



The anhydrous salt then gave : — 



I. 0.3425 grm. of substance, dried at 100°, gave on ignition 0.1353 



grm. BaSO^. 

 II. 0.4383 grm. of the salt, dried at 100°, gave 0.1723 grm. BaSO^. 

 III. 0.2934 grm. of the salt, dried at 100°, gave 0.1153 grm. BaSO^. 



Oaloulated for Ba(C3HBr,0i),. 



Ba 23.03 



I 



