THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.] 



JULY 1896. 



I. Thermodynamic Properties of Air. 

 By A. W. Witkowski. 



[Plates I. & II.] 



Part II * 



Specific Heat. 



§ 1. TN order to obtain a full knowledge of the thermo- 

 JL dynamic properties of a homogeneous gaseous sub- 

 stance it is indispensable to perform upon it a twofold experi- 

 mental investigation : besides its thermometric and dynamic 

 behaviour the calorimetric properties ought to be studied 

 independently. It is known that, in order to solve the first 

 part of the problem, it is sufficient to test the thermal expan- 

 sion of the gas under different pressures and its compressibility 

 at one temperature — or conversely, the compressibility at 

 different temperatures, together with the expansion under a 

 single pressure. This part of the problem I worked out 

 experimentally four years ago ; the results have been pub- 

 lished in the 23rd volume of the Rozpraivy. In the present 

 paper I intend to supplement these investigations by the 

 second, calorimetric part. 



In this respect we may make use of the general laws of 



* Translated from the 32nd volume (1896) of the " Rozprawy " of the 

 Cracow Academy of Science (Math. Class) and communicated by the 

 Author. For Part I., see p. 288, vol. xli. 



Phil. Mag. S. 5. Vol. 42. No. 254. July 1896'. B 



