VALIDITY OF THE PRINCIPLE OF LE CHATELIER. 



33 



Th 



en 



dG 

 dt 



>0 



(54) 



Hence the point moves along the curve in the direction Ai A2, i.e. still 

 farther away from equilibrium. 



On the other hand, the same reasoning applied to a curve sloping 

 downward from left to right shows that the system after displacement 

 returns to its equilibrium position. 



So, for example, the curves representing the relation between pres- 



G 



Figure 1. 



sure and volume of a gas necessarily slope downward from left to 

 right; the same is true of the demand and supply curves of economics. 

 If it were true, as sometimes stated, that the more a man has, the more 

 he wants, economic equilibrium would be an unstable condition. 



External Stability and the Principle of Le Chatelier. Consider now 

 a system which obeys the condition 



^ {x, G, Hy= 



^- = according as H — He^O 

 at < < 



(55) 



(56) 



