BRIDGMAN. — THERMODYNAMIC PROPERTIES OF LIQUIDS. 



73 



bility at 40° was 0.0020 inch on a total of 2.05 inches. The agree- 

 ment is quite perceptibly better than the average. The thermal 

 dilatation measurements show however, by far greater disagreement 

 than any other of the twelve liquids. 0.0030 inch on a mean of 

 0.070 inch. The discrepancy was greater at the higher temperatures; 



12 3 4 5 6 7 8 9 10 11 12 



Pressure* kgm. / cm.^ x 10^ 



Ethyl Iodide 



Figure 19. Ethyl Iodide. Volume at 20°, 40°, 60°, and 80° plotted 

 against pressiu-e. The lower curve is for 20°. 



0.0012 inch from 20° to 40°, 0.0026 inch from 40° to 60°, and 0.0052 

 inch from 60° to 80°. 



The reduction factor from the mathematical formula was 0.9817, 

 showing slightly less than normal compressibility. 



The density at 0° was assumed to be 1.973. The three constants 

 of the dilatation formula were as follows: a =0.0^1054, 6 =0.0c636, 

 and c =0.071004 .^^ Pierre also gives values for the volume at 20°, 

 40°, and 60° respectively; 1.0232, 1.0484, 1.0749, against 1.0214, 

 1.0438, and 1.0677 given by the formula. The agreement should 

 be better. Probably Pierre's values are better, as is shown by the 

 agreement of Amagat's value at 40°, but Pierre does not give the 

 volume at 80°; so the value of the formula was accordingly selected. 



The change of volume between 1 and 500 kgm. was taken from 

 Amagat as 0.0459. Amagat gives for the initial volume at 40° 

 1.0486 against 1.0438 of the formula. The low pressure determinar 



55 Dobriner, Lieb. Ann., 243, 1-23 (1888). 



