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ILLINOIS STATE ACADEMY OF SCIENCE 



tained by dividing the experimental slopes of the log 

 N vs. 1/T curves by the ideal slope calculated from the 

 latent heat of fusion. 



In this chart naphthalene has been taken as the start- 

 ing point. The value of the ideal slope is taken to be 

 970. This corresponds to a latent heat of fusion of 4,450 

 calories per mole, a value which is somewhat less than 



Fig. i: 

 Chart of Relative Internal Pressures. 



that commonly accepted for naphthalene, viz., 4,550 

 calories. In order to fix the positions of the other sub- 

 stances relative to naphthalene, it was found convenient 

 to locate first those substances which had been used as 

 solvents for naphthalene. Now a large number of freez- 

 ing point and solubility curves of binary systems involv- 

 ing naphthalene as solute are given in the literature. 



