456 



Prof. T. Andrews on the 



[Apr. 27, 



with the temperature. The experiments on this subject are now com- 

 pleted, and are described at length in this paper. The final results will 

 be found in the two following Tables. In the first Table the values of a 

 are referred to a unit volume at 0° and under one atmosphere. In the 

 first column the pressure p in atmospheres is in terms of the air- 

 manometer. 



p. 



* (0°-7°'5). 



« (0°-64°). 



« (64°-100°). 



17*09 





0-005136 



0-004747 



20-10 



0-00607 



0-005533 



0-004958 



22-26 





0-005811 



0-005223 



24-81 



0-00700 



0-006204 



0-005435 



27-69 



0-00782 



0-006737 



0-005730 



31-06 



0-00895 



0-007429 



0-006169 



34-49 



0-01097 



0-008450 



0-006574 



For higher pressures than 35 atmospheres a different unit volume 

 must be taken, on account of the liquefaction of the carbonic acid. The 

 next Table contains the values of a, referred to the unit volume at 64°, 

 between 64° and 100° at constant pressures up to 223 atmospheres. 



p. 



a (64°-100°). 



P- 



a (64°-100°). 



17-09 



0-003572 



46-54 



0-004946 



20-10 



0-003657 



54-33 



0-005535 



22-26 



0-003808 



64-96 



0-006512 



24-81 



0-003892 



81-11 



0-008033 



27-69 



0-004008 



106-90 



0-013150 



31-06 



0-004187 



145-50 



0-018222 



34-49 



0-004266 



223-00 



0-008402 



40-54 



0-004596 







As the value of a changes with the temperatures, the coefficients given 

 above are average coefficients for the ranges of temperature specified. 

 It will be observed that the value of a increases with the pressure until 

 a very high pressure is attained, when it changes its direction and 

 diminishes. This apparent anomaly depends upon the carbonic acid at 

 the high pressure having passed from the gaseous state proper to the in- 

 termediate conditions, which the author has formerly described as esta- 

 blishing a continuity between the gaseous and liquid states of matter. 



If we designate by oC the coefficient of elastic force when a gas is 

 heated under a constant volume, we shall have in the case of a perfect 

 (ideal) gas 



