12 



DAVID PRESSMAN 



TABLE 4 

 Van der Waals attraction due to benzene ring 



as is shown by Table 4 (Pressman, Bryden and Pauling, 1948; Pressman, 

 Maynard, Grossberg and Pauling, 1943; Pressman and Siegel, 1953a; Press- 

 man and Siegel, 1953b; Pressman, Siegel and Hall, 1954; Pauling, Pressman 

 and Grossberg, 1944). 



In the several systems listed, the benzene derivative gave good combination; 

 the methyl derivative gave essentially none, except in the case of the benzoyl 

 propionate system and the phenyl-trimethylammonium ion system, where 

 there was a slight combination with the methyl derivative. Moving the ben- 

 zene ring over by one methylene group also decreased combination, except 

 for the phenyl-trimethylammonium ion system. The fit around the latter 



