VELOCITY OF POLYMORPHIC CHANGES BETWEEN SOLIDS. 



71 



when the carbamide was restrained under mercury than when it was 

 free. This is merely another manifestation of some pecuHarity of 

 behavior during the transition that will l)e further commented on 

 in the paper containing the equilibrium data. 



There are measurements at onl\- three points with the carbamide 

 free under mercury; the results for the transition acceleration are 

 shown in Figure 10 and for breadth of the band of indifference in 

 Figure 17. The acceleration with falling pressure is greater than 



0° 



20° 40° 



Temperature 



Carbamide 



Figure 16. Carbamide. The pressure acceleration of the velocity of 

 transition at zero velocity as a function of temperature along the transition 

 line between I and III. 



400 



P 



E 



200 



20° 40° 60° 



Temperature 

 Carbamide 



80° 



Figure 17. Carbamide. The breadth of the band of indifference between 

 the modifications I and III as a function of temperature along the transition 

 line. 



normal, and both accelerations are greater at higher pressures. These 

 data suggest, however, and the suggestion is much strengthened by 

 the other discarded data, that at temperatures between 65° and 100° 

 the acceleration with rising pressure becomes greater, and that the 

 acceleration with falling pressure may even pass through a minimum, 

 to rise again. This may have some connection with the third phase. 

 The band of indifference becomes rapidly less in width at the higher 



