OP ARTS AND SCIENCES. 153 



CH 



II 

 CBr 



I 



coon 



and the tribrompropionic acid made from it by the addition of bromine 

 must of course have the corresponding form, — 



CH^Br 



I 

 CBfj 



I 

 COOH 



Since the formnlte with dyad carbon are in this case excluded, there 

 remains for the dibromacrylic acid in question onlv the structure, — 



CHBr 



II 

 CBr 



I 

 COOH 



Ahhough this conchision is directly at variance with the results 

 which Mabery and I obtained in the study of the dichlordibrompro- 

 pionic acids, it must be confessed, I think, that it is probably correct. 

 Still, since its adoption presents undoubted difficulties, I shall endeavor 

 to bring more direct experimental evidence as to its correctness. 



The dibromacrylic acid of Fittig and Petri, which, as Mabery and I 

 have shown, can be made from brompropiolic acid, would naturally 

 have the form, — 



CBr, 



II 

 CH 



I 

 COOH 



and the acids made in the same way containing two halogens the 

 corresponding, — 



CBrI CBrCl 



II II 



CH CH 



I I 



COOH COOH 



