24 Mr. D. L. Hammick on Surface Energy, 



whereas if a T is a function of v, 



/3J 



— * 



= \ 1 s.£ (vi.) 



r i 

 By substituting in (iv.) and (vi.) the value -j-j for 



Xj5 (of (iii.))> ve g et : 



1 Gp , .. . 



and /3 = j.~. ...... ^n.) 



In order to test the above conclusions, data are needed for 

 surface energy, latent heat, specific gravity, and compressi- 

 bility. For the latter, Tyrer's values (Trans. Chem. Soc. 

 1914, p. 2534) for pressures between 1-2 atmospheres have 

 been used ; his paper contains data for the evaluation of a, 

 the coefficient of expansion. T) r rer r s results extend over the 

 range 0° (-.-boiling-point; hence the latent heat data avail- 

 able are limited. Those used are due to Young unless other- 

 wise stated. The surface energy data have been taken from 

 Jaeger (Zeit. Anorg. Chem. ci. pp. 1-314 (1917)) and 

 from Ramsay, Shields, and Aston's results. It is noticeable 

 that though Jaeger's results, obtained by the "gas bubble'' 

 method, agree very well with the Ramsay values at low 

 temperatures, marked divergencies occur at higher tempera- 

 tures with the more volatile liquids. In most cases therefore 

 the two sets of results have been plotted and those values for 

 the surface energy used that lie on the straight line (or 

 smoothed curve) that runs through Jaeger's low temperature 

 and Ramsay's high temperature values. 



In the following Tables, (iv.) and (vi.) are applied to some 

 liquids and (vii.) and (viii.) to others. The number of liquids 

 available is necessarily limited by the paucity of data. In 

 the column headed e in each table is recorded either 



_L A 



the ratio — (— =e o r — &■ =e. It will be seen from (iv.), 



~d 

 (vi.), (vii.), (viii.) that the ratio e should be equal to 



f~ if a T =f(v) and equal to — 2 if a-^^fiy). In the cases 



where d, the molecular diameter, is required, it has been 

 calculated from the latent heat at the boiling-point from 

 the relation 



x I .j = 6 ^- 



a 

 * The sign of p will clearly be negative. 



