POLYMORPHISM AT HIGH PRESSURES. 



113 



between IV and II by raising or lowering the temperature, as is possi- 

 ble in the case of some other substances, because the boundaries of the 

 region of existence of V are so nearly vertical that a change of tempera- 

 ture does not carry the pressure far enough away from the equilibrium 



4» 6 



Cl 



E 4^11 



be ^ 



m-yy^ 



rv-vi i^^ ^. 



23456789 10 U 

 Pressure, kgm./cm.^ x 10^ 

 Camphor 



12 



Figure 13. Camphor. The calculated latent heats and the changes of 

 internal energy. 



value to ensure completion of the transition. The total change of 

 volume from IV to II can be determined with some accuracy, however, 

 by taking pressure steps long enough to step over the region of V. 



TABLE VII. 



/ Camphor. 



