( 655 ) 



mixtures of carbon dioxide and livdrogen to use the kui p, loq v 

 diagrams, as I found tiiat not onlj the logarithmical diagrams of 

 the pure substances but also tliose of the four mixtures investigated 

 could be made to coincide with the logarithmical diagram of carbon 

 dioxide hy shifting them parallel to each other. 



Unfortunately Quint made only few observations in the neigh- 

 bourhood of the critical point, a circumstance which rendered this 

 investigation rather diflicult. For it is by means of those very parts 

 situated in the neighbourhood of the point of inflection that the 

 superimposing of the diagrams may be obtained in the most accurate 

 way, while in the area of the larger volumes a shifting within rather 

 wide limits does not cause a perceptible deviatio]) of the superim- 

 posed diagrams. Especially the want of observations in the neigh- 

 bourhood of the critical point in the case of hydrochloric acid is to 

 l)e regretted because the ditFerence between the critical point given 

 by Quint and that found by shifting is much larger than we should 

 expect, the diagrams covering each other in a satisfactory way. The 

 more so because, when for ethane and carbon dioxide the diagrams 

 are made covering each other in the observed area the critical poiiits 

 too coincide. 



Here follow the values found, for the different mixtures, as ele- 

 ments of the critical point of the homogeneous mixture: 



In order to make a comparison I have written in this table the 

 plaitpoint elements of the mixtures as observed by Quint, and in 



NT' 



the last line the values of the expression C\ = ~ which here 



Pxk Vxk 



are about the same for all the mixtures, especially in the neigh- 

 bourhood of the special mixture. By means of Quint's data we find 

 however, for HCl, the much larger number C^ = 3,71 ; this deviation 

 evidently must be brought in connection with the other one I mentioned 

 before. 



