428 



Whether an approach to the vahie of equilibrium occurs for constant 

 concentration will depend on the place which the point representing 

 the state, occupies. The part of the figure left of the equilibrium 



(^xaott>. id&fcjci 



Fig. 5, N N IS the equilibrium line. 



G G 'is the sol-gel boundary. 



L L is the line of the imbibition-maxima. 



M M M' M' are Iho boundaries of the region, in which the approach to the 



equilibrium takes place infinitely slowly. 

 aa', bb' etc. represent the changes which the system undergoes. 



line is split up into two parts by M—M, and likewise a line 

 M' — M' is given on the right side of the line of equilibrium. If 

 the state lies above M — M or under M' — M' , an approach to the 

 equilibrium takes actually place; in the portion of the figure between 

 M — M and M' — M' the velocity of the approach is, however, 

 infinitely small, so that every state remains practically constant here. 

 A change of the number of particles in this region can only be 

 the consequence of a change of the concentration. The representation 

 of these two lines rests on the supposition that a change in the 

 number of large particles will be the more difficult as there are 

 already more lai-ge particles present, and as the water-content is 

 smaller. 



