oj the Liquid and Gaseous States of Matter. GC7 



and <£(-)(£ v^mj) 2 is the attraction between two molecules, 

 and 



z — SB a { (n -f iv) 2 + u 2 + v 2 }. 

 t?'„ being the distance between two molecules situated on 

 the same edge of one of the squares. For a proof of this 

 expression see paper («) p. 791. The attraction of the 

 slab of liquid on a cylinder of the liquid of infinite length 

 and unit cross-section, standing with one of its bases on the 

 surface of the liquid, is therefore 



1 n = co v = x> t/ = co tc=ca / v \ r 



"2(2^.5 X 2 2 <f>2 (A 0)5 (n + w), 



&a 71=1 r— -xi u = — » ic=0 X&c / ~ 



where for <p(z) we have now put — <fi 2 ( — , ft ), the factor 2 



giving the number of molecules lying on a plane cutting the 

 cylinder of liquid parallel to the surface of the slab. This 

 expression gives the intrinsic pressure of the liquid. On 



bringing -g a factor of -4 outside the summation sign it 

 may be written 



where 





and K 2 is a constant which is the same for all liquids at 



corresponding states. Since </> 2 ( -,/3) in the expression 



for the attraction between two molecules varies only slightly 

 with the temperature, the value of K 2 will also vary only 

 slightly with the temperature. 



On the assumption, that </> 2 (— -, /3) or K is constant, the 



intrinsic pressure in any given liquid can be calculated. 

 The value of K 2 then becomes equal to 



n = co r=oo «— 00 w- 



1-66 xlCT 4 * 2 2 2" 2 



H= i »=_« «=_„ h.=o {(n + ^ + ^ + w 2 } 3 ' 



where 1'66 X 1()~ 46 * j s the mean value of K obtained from 

 ether and carbon tetrachloride at T c |. The value of the 



* (a) p. 802. 



