BRIDGMAN. — WATER UNDER PRESSURE. 



501 



of volume. It would probably not be possible to extend this curve to 

 very much lower temperatures than are given here. In partial expla- 

 nation of the difference in the behavior of the reaction velocity with 



TABLE XX. 

 Data for the Equilibrium Curve Ice II-Ice V. 





temperature on the two curves II-III and II- V, it is to be noticed that 

 on the latter curve decreasing temperature is accompanied by increas- 

 ing pressure, which of itself would tend to slow the reaction because of 

 increasing viscosity, whereas on the former curve the retarding effect ; >f 

 decreasing temperature is offset by the accelerating effect of deciv-cS- 

 ing pressure. 



The equilibrium points, four in number, are given in Table XX. and 

 Figure 9. These points lie on a 

 straight line, the temperature ris- 

 ing with falling pressure. 



The change of volume points, 

 obtained by the method already 

 described for the II-III curve, are 

 shown in Table XX. and Figure 

 21. The change is sensibly con- 

 stant on this curve. This means 

 that the relation between com- 

 pressibility and dilatation is such 



that the changes of temperature and pressure on the equilibrium curve 

 produce the same change of volume in both II and V. 



•041 



".039 

 N -35° 



o 



o • 



o 



-30° -25° 



TEMPERATURE 



-20" 



Figure 21. The change of volume 

 when V passes to II. 



