Scale of Oscillation Frequenciet. 



:/5o 



1/100 



1/500 



1/2,50C 



Cui'ves of Molecular Vibrations. 



Ethyl a.-, ^-, and y-dibenzoylsuccinates. The curves for the /3- and y-esters are identical, and are indi- 

 cated by stars upon the line at points where measurements of the spectra were made. The curve of the 

 a-ester is indicated by o. 



