OP ARTS AND SCIENCES. 195 



I. 0.61 IG grm. substance gave, on ignition with HgSO^, 0.1151 grm. 

 11. 0.o3*Jo grm. of substance gave 0.0959 grm. K._,SO^. 



Calculated for KCallUrjO, . CsUaBrjO,. Found 



I. n. 



K 7.85 8.45 7.98 



Dihromacrylic Acid. From the pure barium salt we "set free the 

 acid by the addition of liydrochloric acid, and extracted it from the 

 solution witli ether. The ether left, upon evaporation, a wliite, crys- 

 talline acid, which was very soluble in alcohol, ether, or chloroform, 

 and but sparingly soluble in benzol, carbonic disulphide, or ligroin. 

 Under water, it melted at about 20°, dissolved in every proportion on 

 heating, and was but slowly volatilized with steam. The acid, when 

 melted under water, could be made to crystallize either by cooling with 

 ice or by the addition of a mineral acid. After recrystallization from 

 benzol, it melted at 83-84°, and this melting point we were unable to 

 raise by further recrystallization from this or other solvents. 



Although our analyses left no doubt of the formula of the substance, 

 they showed that it was still impure. 



I. 1.3074 grm. substance gave 0.7692 grm. CO. and 0,1121 grm. 

 11,0. 

 II. 0.9833 grm. substance gave 0.5797 grm. COg and 0.0877 grm. 

 H,0. 



III. 0.2042 grm. gave 0.3366 grm. AgBr. 



IV. 0.2447 grm. gave 0.4044 grm. AgBr. 

 V. 0.2083 grm. gave 0.3453 grm. AgBr. 



VI. 0.2005 grm. gave 0.3309 grm. AgBr. 

 VII. 0.2132 grm. gave 0.3517 grm. AgBr. 



V. VI. TO. 



70.53 70.23 70.20 



Our results had sufficiently established the fiict that a dibromacrylic 

 acid was formed from mucobromic acid by the action of baric hydrate 

 in the cold, but a more extended investigation of it was evidently 

 needed to determine the nature of the impurity which was so difficult 

 of removal. Since Wallach and Reincke* had shortly before an- 



* Beridite der deutsch. cliem. Gesellscli. x. 2128. 



