154 



PROCEEDINGS OF THE AMERICAN ACADEMY 



The tribrompropionic acid melting at 118° would be written, — 



CHBr^ 



I 

 CHBr 



I 

 COOH 



and the tetrabrompropionic acid would have the form, — 



CHBr^ 



CBr, 

 I 

 COOH 



VI. Crystalline Form op Tribromacrylic Acid. 



By W. H. Melville. 



101 



001 



1.00 



MonocUnic System. 



Forms, {010} {110} {011} {101} |T01} {021} ; the last three 

 forms being rarely observed. 



Elements : Clinodiagonal a = 0.502 

 Orthodiagonal b = 1. 

 Vertical axis c = 0.559 

 Angle of axes XZ = 64° 29^' 



