Velocity of Reaction before Complete Equilibrium. 271 



in detail in my publications of 1896 (see Proc. of the Royal 

 Society, 1896; Zeitschrift fur physikalische Chemie, January 

 1896) are essentially necessary for securing reliable results 

 of great accuracy. In the theoretical treatment of the 

 subject of freezing-points, there were some essential differ- 

 ences between Nernst and myself, and as it is now intended 

 to extend the problem to a very much larger field (of vapour- 

 pressures, boiling-points, sublimation-pressures, solubility, &c.) 

 it becomes necessary to deal here in a few words with those 

 differences. 



In his theoretical consideration of the subject of freezing- 

 points Nernst started (see Zeitschr. fur physik. Chemie, 

 1896 ; see also full translation in my paper, Phil. Mag. 

 December 1897) from the experiments of Boguski on the 

 velocity of solution of metals and marble in acids. He there 

 makes the assumption that the velocity of ice-melting repre- 

 sents the same kind of phenomena as those observed by 

 Boguski, and that it consequently has to be expressed by the 

 equation given by Boguski for the above reactions. He further 

 correspondingly assumes that the apparent freezing-point 

 always depends on the velocity of ice-melting, the term 



V(t g -t) . . 



- — 7w~ having a positive or negative value according as 



t g (the convergence temperature) is greater or smaller than 

 t' or t , i. <?., is above or below the freezing temperature. On 

 the contrary, I thought that between the reactions of Boguski 

 and that of ice-melting there is no analogy whatever, both 

 representing reactions sui generis. My considerations of the 

 theory of the subject icere based on the notion of perfect equili- 

 brium, and the conclusion was arrived at that when the 

 convergence temperature is above the freezing-point the 

 reaction of ice-melting, and when below that of ice separation, 

 is to be taken into account. The two reactions are of opposite 

 kind, must or may have different velocity constants, and have 

 first to be studied and investigated independently. As will 

 be seen later on, this conception proved to be the correct one. 

 Not only does the reaction of Boguski and that of ice-melting 

 prove each to be sui generis, but Boguski's equation for the 

 velocity of solution of metals and of marble in acids is, in all 

 probability, an incorrect one, contradicting as it does the 

 well-established laws of mass action ; the phenomenon itself 

 represented by Boguski's reaction has not been (as will be 

 seen later on) even correctly conceived in its true nature, 

 though the misconception was a natural one. 



Having now arrived at the result that the velocity of all 



