The final quantity 0-386 of y-pentane was practically the 

 same as the 0-387 left on heating pure y-pentane for 

 sixteen hours at 210-5, and the course of the reaction 

 corresponds to the equation that may be expected in such 

 a transformation : 



dx ' f . 7 

 = k(i-x)-k L x, 



that is, two unimolecular processes going in opposite senses. 

 In the final condition 



= o, so that k (i x) = k L x, 



tit 



and since 



x = 0-386, Jc 1 k i -591, 



so that 



dx 



= /c(i- 



whence 



-\ log (1-3-5910) 



must be constant, as the third column of the above table 

 shows. 



It may be added that Walden observed the same state of 

 equilibrium between two isomers in the spontaneous forma- 

 tion of racemates. Active bromosuccinic ethyl ester, e. g., 

 gradually loses its activity by transformation into a mixture 



I 



