1904] Physical Constants at Low Temperatures. 



257 



Oxygen v = 1-9305 - 0*5838 log (154 - f), 



V = 20-90, c/d = 3-3. 



Nitrogen v = 2*5659 - 0-7868 log (127 - t), 



V = 25-80, c/d = 3-27. 



Carbonic oxide v = 2-6181 - 0-7948 log (133 - f), 



Y = 26-04, c/d = 3-29. 



Argon v = 1*6331 - 0*5026 log (155 - 1), 



Y = 21-30, c/d = 3-70. 



This same formula has been adopted by Mallet and Friderich,* 

 subject to the modification that A is a unique temperature to be deter- 

 mined for each substance from experiment. On applying it to twenty- 

 five substances, studied by Sydney Young, they find that A is somewhat 

 higher than the critical temperature and that c/d is always very nearly 

 equal to 3*78. Baly and Donnan's observations give rise to these 

 AYaterston-Mallet equations : — 



Oxygen v = 3-88413 - 1-3604 log (253 - t), 



V = 19-68, c/d = 2-86. 



Nitrogen v = 3-1563 - 1-0560 log (143*67 - t), 



V = 24-58, c/d = 2-99. 



Carbonic oxide ... v = 4*60090 - 1*64207 log (191*1 - t), 

 V = 23-94, c/d = 2-80. 



Argon v = 0*98285 - 0*19263 log (112*4 



Y = 23*52, c/d = 5*10. 



VYith assumed values for A, in the neighbourhood of the range of 

 temperature in which we look for the critical temperature, two 

 Waterston-Mallet formulae were constructed for hydrogen based on the 

 results of Table III, namely : — 



v = 23*22 - 7*536 log (36*5 - t% Y = 22*90, 

 v = 26-83 - 9-592 log (41*5 - 1), Y = 22*62. 

 Assuming that for liquids Yanider Waals's equation may be written 



an assumption which has been employed by G. N. Lewis f and others, 

 the results of Table III give for hydrogen, with this equation, 

 6= 11*56 and hence Y = 23*12. 



For comparison these values may be arranged in tabular form 

 thus : — 



* 'Arch. Sci. Phys. et Nat.,' July, 1902. 



f ' Araer. Acad. Arts and Sci.,' 1900, vol. 35, pp. 1—27. 



