44 Mr. D. L. Hammick on Latent Heat 



also makes it unnecessary to compare liquids at corresponding 

 temperatures. 



A " general " value for - — will now be calculated from 



(5) at the boiling-point, using the following data : — 



R = 2 calories = 2x4-18xl0 7 ergs, a =1-62, y = 2"7, 



* = l-4, ^=3'7, ~=1X10- 8 . 



We obtain - — = K— 2*17, in very good agreement with 



the empirical value. 



In Table IV. will be found some calculations of K for a 

 few individual liquids at the boiling-point and at some other 

 non-corresponding temperature. 



Here again, in the case of argon and nitrogen, theory is 

 able to predict " abnormal '' values. 

 From the equation 



pV ^_Li 

 d ' J ~ 6 

 we have T7 a T d 1 



At the boiling-point ^ has been found to be 1'OxlO -8 



for many liquids. We therefore have 



d( P V*) _d f 1 dL 1 _L } 1^ dV\ 



dT "6\V* ' dT 3 "Vt ' dTJ 



10- 8 « ^Li L, 



6 



)^T-3^j' 



where #=_ . _ —coefficient of expansion. 



Expressing L x in ergs (J = 4*18 X 10 7 ergs), 



-^r-^-{jF~ Lia )' • • • ( 6 ) 



<*m = . m$-X*). . . . (6a) 



This relation is implicit in the combination of equation (1) 

 and Bakker's equation used to calculate latent heats at 

 various temperatures, and a special test of it is therefore not 



