( 238 ) 



Fig. 4 



llio hraiicbes A A' and /.7>" haw met, and so there is a miiiimnni 

 valne for the valne of .rj^. 



To tlie second case applies tig. 5. Then the curve AB will move 

 to the right witii decreasing teniperatnre. With decreasing \alne of 

 T the branches A' A and BB' will approach each other; and this 



Fisr. 



