^4. J. Lotka — Mode of Growth of Material Aggregates. 207 



which, in the presence of excess of alcohol and water, is raono- 

 niolecular in either sense. According to the values of the 

 velocity coefficients observed by Kistiakowski,* at 25° C. in a 

 solution containing 73'2 per cent alcohol, the mean " length of 

 life " of a molecule of formic acid is here 7 hrs. 36 mins., while 

 that of a molecule of ethyl formate is 12 hrs. 6 mins. 



Representing the history of the aggregate A (ethyl formate) 

 by an ~N' t c(a) surface, we should obtain a figure such as that 

 indicated below. 



l 



k = -00138 



We have not the requisite data for constructing the entire 

 !S\ t c{a) surface for A'; when equilibrium is reached, however, 

 * Zeitschr. L phys. Chemie, xxvii, 1898, 250. 



