442 Mr. Gervaise Le Bas on the 



Toluene. 



M.V. 118*25. 



// \ VC 6 H 6 96-0-3-2 92-8 



CH CH CH 3 25-45 



' | 2A.V 118-25 Schid 



CH C — CH 3 ^= aa - 



^ / A —14-5 



CH 



p-Xjlene. 



C — CH 3 M.Y. 140-40. 



P1 f \ R VC 6 H 4 96-0-2x3-2 89-6 



I ij 1 2CH 3 50-9 



CH CH 2A.V 140-5 



C — CH 3 a —14-1 



Mesitylene. 



CH 3 M.V. 162. 



I V C 6 H 8 960-3x3-2 86-4 



C 3CH 3 76-35 



CH CH ^5 



CH 3 -C C — CH 3 A ~~ U6 



CH 



The contraction of —15 in benzene is thus in part due to 

 the diminished volumes of the hydrogen atoms. 



The almost strict accuracy of the above results is not 

 usually met with, because minor effects cause the values to 

 vary a little. The average contraction for benzene deriva- 

 tives is about —14*7. 



% 



