BRIDGMAN. — THERMODYNAMIC PROPERTIKS OF WATER. 359 



that is, the curves are goinj; to cross again, and the thermal (Hlation 

 become greater at the higher temperatures. This may possibly 

 indicate a reversal of the reversal of the effect mentioned above for 

 liquids, but more probably the meaning is simply that at pressure 

 above 12,000 the substance is practically a solid, and that for solids 

 the reversal of the effect found in liquids at high pressures does not 

 occur. 



There is one bearing which these observations have on the previous 

 data which should perhaps be mentioned. This is in connection with 

 the delayed freezing. Whenever freezing takes place there is usually 

 the possibility of subcooling before separation to the solid form takes 

 place. The amount of subcooling usually taking place depends on 

 the nature of the liquid. In some it is very considerable, while in 

 others it is negligible. If such subcooling took place here, it would 

 produce irregular results, because the change of volume in the kero- 

 sene transmitting pressure to the water would not always be the same 

 under the same pressure. The only answer to be made to this ob- 

 jection is that in this experiment the subcooling was not great enough 

 to produce sensible irregularity. No discrepancies were found in the 

 data suggesting that they were due to this effect. It was feared in the 

 beginning of the work that the effect might be very troublesome, but 

 such did not turn out to be the case. 



Also with respect to the solidification of the kerosene, the experi- 

 ments showed that the solidification could not be complete, but the 

 kerosene, even at the highest pressures, must remain a pasty mass like 

 vaseline in nature, always capable of transmitting pressure nearly 

 hydrostatically. But that on the other hand the kerosene does 

 undoubtedly become pretty stiff under pressure has been already 

 shown in the course of some measurements on the linear compressi- 

 bility of steel rods. 



The second bit of data collected incidentally in the course of the 

 work was a measurement of the expansion and the thermal dilatation 

 of the high temperature variety of ice. 



The Compressibility and Thermal Dilatation of Ice VI. 



Although these data are not directly concerned with the properties 

 of liquid water, which forms the subject matter of this paper, still 

 it was so easy to obtain them without any modification in the arrange- 

 ment of the apparatus, that it was thought worth while to measure 

 them. In the previous paper on the properties of water and the 



