( 226 ) 



Pk Pk"" Pk* 



Pk ï>k 



and the reduced virial coefficients ^, ^, £),(?, 5 with t = 7— are 



Jk 



determined bj 



The calculations ^vhich show the systematical deviations of different 

 normal substances from a similar equation of state are progressing. 



§ 3. Validity of the law of corresponding states for mixtures. We 

 can judge of this much better now than when Comm. No. 59^7 Avas 

 written. The different applications given in this series of Contributions 

 to tlie knowledge of van der Waals' ifvsurface ^) seem to indicate 

 that the deviations in mixtures of normal substances are not much 

 larger than those Avhich occur in normal substances inter se. 



This is verv striking, especially if we look for the basis of the 

 law of corresponding states in the mechanical similarity of the move- 

 ments, as a mixture even geometrically is not at all similar to a simple 

 substance. It would seem to follow from this, that the linear quan- 

 tity which determines the geometrical scale of similarity is a mean 

 value of very different linear quantities, which play parts in different 

 collisions. In that case we should have to attach to the "volume of 

 a molecule" not so much a physical meaning and rather the geome- 

 trical meaning of a sphere drawn with this linear quantity as a radius. 



To establish a systematical relation in the deviations of the mix- 

 tures of normal substances from the law of corresponding states 

 is not likely to be feasible until this has been done for the devia- 



i) Comm. No. 59Ö Kamerlingh Onnes and Reinganum. Comm. No. 64, Hartman. 

 Comms. Nos. 65, 81, Suppls. Nos. 5, 6, 7 Verschaffelt. Comms. No. 75 and 

 No. 79 Keesom. 



