A Relation Between the Fluidity and the Temperature 

 OF Liquids. — By Henry Jermain Maude Creighton, 

 Assistant Professor of Chemistry in Swarthmore College, 

 Swathmore, Pennsylvania. 



(Read 13 March. 1922) 



Some years ago it was shown by Ramsay and Young* that 

 for any pair of closely related substances — such as methyl 

 acetate and ethyl acetate, or propyl propionate and propyl 

 butyrate — the ratio of the absolute temperatures (T) corres- 



T', T, 

 ponding to equal vapour pressures is constant, /. e., = = 



T' T 



* B * B 



constant. For substances not closely related it was found that 

 the relation was less simple, but that it might be expressed by 

 the equation, R' = R + c(t' - t), where R' is the ratio of the 

 absolute temperatures of the two substances corresponding to 

 any vapor pressure, the same for both; R is the ratio of the 

 absolute temperatures at any other vapor pressure, again the 

 same for both; c is a constant; and <' and t are the temperatures 

 of one of the substances corresponding to the two vapour pres- 

 sures. This relationship was tested by Ramsay and Young 

 for 23 pairs of substances, and has also been found to hold up 

 to the critical point. The method has been employed by Ram- 

 say and Travers* to calculate the vapor pressure of the inert 

 gases argon, krypton and xenon. 



At the suggestion of Ramsay, Findlay^ showed that a pre- 

 cisely similar equation to that of Ramsay and Young connects 

 the absolute temperatures at which two substances have equal 

 solubilities, and also the two absolute temperatures at which 

 two chemical equilibria have equal equilibrium constants. 



The writer has recently found that the two absolute temper- 

 atures at which two substances have the same value for other of 

 their physical constants are related by an equation having this 

 same form. In this paper the relation between the fluidity 

 (reciprocal of viscosity) and the absolute temperature of liquids 

 is presented briefly. 



The constant c in the equation R' = R + c(t' - t), where 

 R' and R are the ratios of the absolute temperatures of two 



1. Phil. Mag.. (5), 20. 515 (1885): 21. 33 (1886). 



2. Phil. Trans.. A.. 197. 47 (1901). 



3. Proc. Roy. Soc.. 69. 471 (1902). 



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