OF ARTS AND SCIENCES. 221 



CBr„ — CHO CBr. — COOH 



! I 



= C — COOH = C — Clio 



The ease with which it is decomposed, even in the cold, by alkalies 

 and the aldehyde group thus converted into formic acid, would pos- 

 sibly incline one to adopt the first of these formulae. 



Unfortunately, no independent evidence concerning the position of 

 the bromine atoms can as yet be drawn from the constitution of the 

 dibromacrylic acid, which is formed at the same time, since none of its 

 reactions give a clew to its structure. It may only be asserted, with 

 tolerable certainty, that its formula is not, — 



CBr„ 



II 

 CH 



COOH 



since the corresponding chlorinated acid made from mucochloric acid 



appears to be essentially different from the dichloracrylic acid of 



Wallach, and the formation of the latter from chloralid shows its 



formula to be, — 



CCL 



II 

 CH 



I 

 COOH 



If the structure of mucobromic acid is represented by one of the 

 formulae given above, it follows that the dibromacrylic acid obtained 

 from it has one of the forms, — 



CBr„H = CH 



I I 



= C CBr„ 



1 I 



COOH COOH 



The formation of a tribrompropionic acid, melting at 116-117° by 

 the addition of hydrobromic acid, would in itself be a sufficient reason 

 for rejecting the second formula, if the structure of the tribrompro- 

 pionic acid, melting at 92°, could be shown to be, — 



