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PROCEEDINGS OF THE AMERICAN ACADEMY. 



pressures was also a surprise. The grand average for the dilatation 

 at 12000 kgm. for the twelve liquids is 0.00025, about 40% more than 

 that of mercury at atmospheric pressure and much higher than for 

 any solid except possibly gutta-percha. It is ten times as great as 

 that of aluminum, for example. The very slow change of dilatation 



TABLE XVIII. 



Pressure at which the Thermal Expansion is twice as large as it is 



AT 12000 KGM. 



with pressure is shown in Table XVIII, giving the pressure at which 

 the dilatation has twice its value at 12000 kgm. The table shows 

 that between atmospheric pressure and 2400 kgm. (on the average) 

 the dilatation falls to about 0.4 its initial value, while over a further 

 pressure range four times as large it falls off only an additional 50%. 

 From these data it would appear that the dilatation must remain very 

 considerable for pressures far in excess of those reached here. The 

 approximate equality of the pressures for the twelve liquids at which 

 the dilatation is double its value at 12000 kgm. indicates that the 

 liquids behave similarly over much the greater part of the pressure 

 range. 



The curves in general fall with increasing pressure, but all the 

 alcohols show a tendency to become stationary or to rise ; while carbon 

 bisulphide shows an extended stationary region between 6000 and 

 10000 kgm. but beyond 10000 its curve drops with unusual steepness. 



The four normal alcohols show a dilatation continually decreasing 



