BRIDGMAN. — WATER UNDER PRESSURE. 



485 



The Curve III-L. 



The points on this curve were more difficult to obtain accurately 

 than those on any of the other nine equilibrium curves. This is 



TABLE XII. 

 Data for the Equilibrium Curve Ice III-Water. 



because of the extreme slowness of the 

 reaction, accounted for in part by the 

 comparatively small change of volume 

 and the large heat of reaction. This 

 does not prevent, however, a fairly 

 accurate knowledge of the properties 

 of the curve, since the curve is short, 

 reaching over only 1500 kgm., and it 

 is tied down by a triple point at 

 either end. 



The apparatus used for this curve 

 was that of the mercury determina- 

 tions, temperature being kept constant 

 with a thermostat. This was neces- 

 sary because of the great effect of 

 temperature on the equilibrium pres- 

 sure on this curve. 



Five points on the equilibrium curve 

 were obtained, and two on the change 

 of volume curve. These are shown 

 in Table XII. and Figures 9 and 12. 

 The equilibrium points are satisfac- 



Y 



---\ 



.045 





.040' 





.035 



5 



tiJ 



.030^ 



> 



025 u 

 o 



,020 



< 



X 



o 



-2^° -20° -18" -16 

 TEMPERATURE 



Figure 12. The change of vol- 

 ume when III passes to the liquid. 



