196 



Albert P. Mathews 



(2) Val. number = = 0.0043 T s c /P c s/ *(Mol. Wt.); or, if 

 the calculation is made from the temperature and volume: 

 (3) Val. number = 4.21 -X iQ- 5 X (V c T c ) 8/ */(Mol. Wt.). 



-37.56 



Fig. i Showing the relationship between the logarithm of M 2 K and the 



logarithm of the product of the molecular weight by the 



number of valences 



In these formulas V c is the critical volume of a gram mol. in 

 cubic centimeters; T c , the absolute critical temperature; 

 and P c the critical pressure in atmospheres. 



