Reaction before Complete Equilibrium. 473 



At equilibrium T becomes C : 



^=c'Co(2o-f-K)^ c / C o (S o + K)=0. 



Thus we could understand the equation (a) or (a!), taking as 

 an instance for consideration the separation of salt from 

 supersaturated solution, in this way : 



and the resulting equation from it 



(£) -**«.+*), 



give the velocity with which the solid salt is passing into the 

 solution before and at equilibrium, G being the active mass 

 of the solid per unit surface expressed in the value of con- 

 centration of the solution at equilibrium ; and 



(J)'= c <c t(5 UK), 



and the equation resulting from it 



(J)' =<*X(2„ + K), 



give the velocity of separation of salt from the supersaturated 

 solution before and at equilibrium. This means that the 

 velocity of solution of the solid is directly proportional to its 

 surface at the time t* (+ the instability constant K) ; the 

 velocitv with which the dissolved salt transforms into solid 

 salt is directly proportional to its concentration in the solution 

 and to the surface of contact of the solid with the solution at 

 the time t* (+the instability constant K) ; equilibrium is 



* It should be remarked that the instability constant K cannot be dis- 

 posed of and explained as an increase of the surface produced by the 

 crystal of ice or salt which is introduced into the overcooled or over- 

 saturated solution in order to start the reaction. In cooling down in my 

 experiments, e.g., 4| litres of water 0°-4 below C , 22-5 c. cm. H 2 6 

 separated in form of ice ; the introduced small crystal cannot possibly 

 amount even to 0°01 c. cm. water or ice, i. e., it cannot amount to 

 1/2250 part of the total amount of ice separated. The value of K, however, 

 is found not to be so small, but in the above experiment =1/10 part of 

 t — Tov or of the total amount of ice separated during the reaction, and 

 much exceeds the value t — tot at the beginning of the reaction. It should 

 also be remarked that the instability constant shows an additional strain 

 in the liquid removed from the point of equilibrium, which forces the 

 same to strive at a state of equilibrium, it therefore always increases the 

 velocity of reaction and K is always positive. 



Phil. Mag. S. 6. Vol. 4. No. 22. Oct. 1902. 2 I 



