158 Mr. G. von Kauf mann on the Theory of Corresponding 



In fig. 1, the logarithms of <p l9 <£ 2 , tt, 0, as obtained by 

 these two equations, are plotted as functions of log 10 (l + ; 



Fig.l. 



log„OW 



The curves are all drawn to the same scale, the ^-curves being moved 

 tioo units upwards, and the 7r-curves moved seven units upwards 

 as indicated by the small figures. 



and fig. 2 gives the curves showing log it as f unction of log 0. 

 The latter curves may be compared with experimental loga- 

 rithmic vapour-pressure curves, as a test of the equations by 

 the method of Raveau. Clausius' equation here gives a curve 

 of the same shape as that given by Berthelot's, but shifted 

 according to the value of X, and the resulting values of ir k 

 and k . According to the usual value of ^ k ^ k \0 k — 0*266 

 approx. : the value of X for most substances would be 

 about 6*5. 



If the values of <f>i, (f> 2 according to Ciausius' equation 

 .are required, they are readily obtained from the tables as 

 follows : — Let <I> be any value of <£i or <p 2} as obtained from 



