VALIDITY OF THE PRINCIPLE OF LE CHATELIER.' 23 



established. But, starting from the stationary state, at which 



dx 



— = f = 0, increase in G leads to a positive value of /. That is to 

 dt 



say, a change actually takes place with a velocity directed towards the 

 new stationary state, i,e. increased oc. 



b.) — :; < 0; i.e. increase in the paramenter G retards the trans- 

 dG 



formation. Here it follows by similar reasoning that increase in G 

 shifts the position of the stationary state towards diminished trans- 

 formation. Furthermore, in this case the increment 56' initiates a 

 retrograde change, i.e. a change toward the new stationary state. 



In both cases, (La) and (l.b), therefore, a change 8G in the para- 

 meter G is followed by a transformation 8xi towards the new sta- 

 tionary state, in the direction of the influence of the parameter G 

 upon tl^ie velocity of transformation. 



5, Unstable State. 



df 

 Consider now the case in which — > 0. The stationary state de- 



dx 



fined by (2) is then unstable. A train of reasoning precisely analogous 



to that set forth above leads, in this case, to the conclusions: 



(1) A change 8G in the parameter G determines a shift of the 

 stationary state in the direction opposed to the influence of the para- 

 meter G upon the transformation. 



(2) The system, disturbed from existing stationary state by a 

 change 56', moves, not towards, but away from the new stationary 

 position. 



Application to Influence of Initial Masses. Consider a transforma- 

 tion 



Sl+ ^2+ ...+ SrZ S'l-\- S'o+ . . . + S\ (6) 



Let ^1, ^2, . .^r be the masses (expressed in mols) at time t of the 

 components Si, S2 . .Sr', similarly let ^'1, ^'2 -^'s be the masses of 



S 1, S 2- ■ ■ S s 



Let X measure the progress of the transformation from left to right, 

 and let pi x be the amount . (in mols) of S, transformed from time 

 t = to time t = t. 



Let Ai be the initial value of the mass (in mols) of some component 



