POLYMORPHISM AT HIGH PRESSURES. 



121 



numerical results in Table VIII. As is evident from the irregularity 

 of the points, there are difficulties in the way of accurate measurement 

 that need comment. On the II-IV line the change of volume is so 

 small that it was not possible to obtain equilibrium values of the pres- 

 sure even by the method of artificially ^■arying pressure after the 



12 3 4 

 Pressure, kgm./cm.^ x 10^ 

 Potassium Acid Sulfate 



Figure 15. Potassium Acid Sulfate. The observed differences of volume , 



12 3 4 5 6 

 Pressure, l<gm./cm.^ x 10^ 



Potassium Acid Sulfate 



FigureTIG. Potassium Acid Sulfate, 

 the changes of internal energy. 



The calculated latent heats and 



