﻿988 Dr. J. R. Partington on the 



change of direction o£ motion of the air entering the channel 

 or orifice. 



The work detailed above was carried out in the Physical 

 Laboratory of the South Metropolitan Gas Company ; and 

 the author desires to express his sincere thanks to Dr. Charles 

 Carpenter, C.B.E., for the provision of facilities for carrying 

 out the investigations, and for his continued interest in the 

 work. 



709 Old Kent Road, S.E. 15. 

 14 Aug., 1922. 



LXXXVII. 2 he Chemical Constants of some Diatomic Gases. 

 By J. R. Partington, D.Sc* 



1. npHE Theorem of Nernst supplements the two Laws of 

 J- Classical Thermodynamics by assigning to the 

 constant of integration, I, of the Reaction Isochore of Van't 

 Hoff (1) a value otherwise determinable only by experiment 

 with the particular system of materials under consideration : 



d\og e K/dT = Q v /RT 2 (1) 



lo ge K=-Q„/RT + I (2) 



According to Nernst, I = £m, (3) 



i. e. the integration constant is represented as the algebraic 

 sum of the products of the numbers of interacting molecules 

 (n) by the chemical constants (i) of the various pure gaseous 

 materials taking part in the reaction. 



2. The value of i is the constant of integration of the 

 Clapeyron-Clausius equation, simplified by the usual approxi- 

 mations 



X T = RT a .rflog.p/rfT, (4) 



where X T is the latent heat of vaporization per gram molecule 

 at the temperature T. The value of X T as a function of 

 temperature is given by KirchhofFs equation 



\ T = \+((C p -c)dT, 



(5) 



where G p is the molecular heat of the vapour at constant 

 pressure, and c that of the condensed phase. Thence 



log e p=-^ + ^~^(C 1> -c)dT + i. . (6} 

 * Communicated hy the Author. 



