470 Dr. Meyer Wilder man on the Velocity of 



place, but the equilibrium is nevertheless of a dynamic nature. 

 In other words the above equation (ii.) is to be understood 

 in this way : we have 'partial velocities of each of the two 

 opposite reactions : 



g)=K^^...,(|)'=KV»'W-'..-; 



the total velocity before equilibrium is : 



find at equilibrium we have I -j- ) = ( -j- ) 



It Y 

 or 



dt 



■~j-=Kp^p 2 n * K'p^'pJ^^O, . . (iv.) 



and ]^>F = ir = const * ( iv '-> 



* I. e., at equilibrium the substances taking part in the two opposite 

 reactions are all present, as before equilibrium, being regulated by iv. or 

 iv.', and none of the substances can disappear because none of the velocity- 

 constants K or K' equals zero. It should be remarked, reversing the 

 argument, that the same two reactions, which take place at equilibrium, 

 take place before equilibrium, witli the same velocity constants K and 



, (dt \ . (dt \ x ,dt\ 



Iv , ( r- J being either >or< f -r 1 . At equilibrium neither I -v- 1=0, 



/dt \i (dt\ (dt\f 



nor i-r ) =0, but ( -^ J — ( ^- J =0. This conception can be shown 



to be true in homogeneous systems, and not to be a mere theoretical 

 (dynamical) conception which can just as well be replaced by another 

 one, for the reason that it can be shown to be true in all its details 

 experimentally : in cases of chemical equilibrium in homogeneous systems, 

 each of the two opposite reactions can be isolated and studied separately 

 so as to get the constants K or K/ separately. For this it is enough to 

 start with a system in which the reacting substances of one reaction are 

 in great preponderance over the substances of the opposite reaction, 



so that (-T- J — I -j ) can for a sufficient time be taken to be equal to 



(j-j or to \-j~) respectively, and the values K and K' separately 



determined. We find then that equilibrium actually takes place just when 



becomes = ^ =C, i, e., the whole conception in all its elements 



from the beginning to the end can be tested (in homogeneous systems) 

 -experimentally, and proves to be correct. 



