and 1li<' KI/H i/.Hn-i u HI Constants of Chemical Reactions, etc. 475 



factory. An equally good agreement was also shown in the other 

 cases which I investigated. From the considerable number of cases I 

 have studied, it would appear that the above method can l>e applied 

 to the calculation of solubilities with close approximation to the 

 truth. As to the range of temperatures or solubilities over which 

 the relationship holds good, no definite statement can be made as 

 yet. In almost all cases the relationship was tested over the whole 

 range of available data ; that is to say, over the range of tempera- 

 tures within which the two substances under comparison have equal 

 solubilities. Several of the deviations are no doubt due to inaccuracies 

 in the determination of the solubilities, and to errors in the drawing 

 of the curves or reading from them. 



II. Calculation of Equilibrium Constants. The formula of Ramsay 

 and Young, further, can be applied not only, as has already been 

 shown, to the calculation of vapour pressures and of solubilities, but 

 it can also be used for the purpose of calculating the equilibrium 

 constants of chemical reactions. In this case, R and R' denote the 

 ratios of the absolute temperatures at which the values of the equili- 

 brium constant of the two reactions arc equal. In this case, also, 

 if we know the temperature curve of the equilibrium constant 

 of one reaction, it will be possible to calculate the temperature 

 curve of the equilibrium constant of another reaction, by determin- 

 ing the value of that constant at t\vo temperatures. This is shown 

 by the figures given in Table VI. The two reactions which were 

 compared were those represented by the equations 2111^11... + I..,* 

 and 2CH 3 . CO . CH 3 ^CH ;! . CO . CHo . C(CH 3 ),.OH,t two reactions, 

 therefore, which are of a most dissimilar character. As the values 

 of the equilibrium constant of these two reactions were not determined 

 at a sufficient number of suitable temperatures for the present pur- 

 pose, it was necessary to calculate the values of the constant at 

 other temperatures. In the case of hydriodic acid, the constant was 

 calculated for the temperatures 520, 530\ 540, 550, 560, by means 

 of the formula given by Bodenstein :| 



log e K = ^1 8 - 1-5959 log, T + 0-0055454T + 2 -6981. 



The values found were : 



t 520 530 3 540' 550' 560' 



K 0-02063 0-02658 0-02759 0-02864 0-02974 



In the case of the condensation of acetone to diacetone alcohol, in 

 which case the equilibrium constant was determined at only two 



* Bodenstein, 'Zeitschr. Pliysik. Chein.,' 1899, vol. 29, p. 293. 

 t Koelichen, ' Zeitschr. Phvsik. Chem.,' 1900, vol. 33, p. 129. 

 T Loc. cit. 



