THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



FEBRUARY 1892. 



XVI. On the Generalizations of Yan der Waals regarding 

 "Corresponding" Temperatures, Pressures, and Volumes, 

 By Sydney Young, D.Sc, Professor of Chemistry, Uni- 

 versity College, Bristol*. 



[Plates I.-IIL] 



IN his dissertation Die Continuitdt des gasformigen und flus- 

 sigen Zustandes (Roth's translation, Leipzig, 1881, p. 128) 

 Yan der Waals has deduced the following generalizations from 

 his fundamental equation 



(p+ £)(»-&) =R(l+«f). 



If the absolute temperatures of various substances be propor- 

 tional to their absolute critical temperatures, their vapour- 

 pressures will be proportional to their critical pressures, and 

 their volumes, both as liquid and as saturated vapour, will be 

 proportional to their critical volumes. 



At the time, however, that Yan der Waals's great work was 

 published, the available experimental data were insufficient to 

 satisfactorily test the accuracy of these generalizations. 



Since then the conclusions of Yan der Waals have been 

 subjected to a large amount of criticism, both adverse and 

 favourable; and while it is now generally recognized that the 

 relations between the temperatures, pressures, and volumes of 

 liquids and gases cannot be represented by so simple a 

 formula as that quoted above, it has nevertheless boon 

 accepted as correct by some authors, w r ho have made it the 

 basis of further generalizations. 



And although the general verdict with regard to the strict 

 accuracy of the formula itself can hardly be considered 



* Communicated by the Physical Society : read November <3, 1 89 1 . 

 Phil. Mag. S. 5. Yol. 33. No. 201. Feb. 1892. M 



