483 



If we take the value 1630 for the molecular heat of evaporation 

 for all the lempcralures in the field considered, a vahie which is 

 cliosen willi a view to obtaining the best correspondence, and which 

 is not contrary to an extrapolation of tlio values of X for the liquid 

 given below then we tlnd the following. 



The correspondence , obtained in this way, may be considered on 

 the whole satisfactor3\ 



I have to thanlv Mr. W. H. Keesom for many useful suggestions 

 in connection with these calculations. 



§ 3. The triple point. 



The triple point constants as observed are given in Table I. 

 Calculation showed that the break of the two curves in argon is in 



the usual direction. In order to determine the values of ( —j 



and I — 1 at the triple point as sharply as possible, I cal- 



y tt J y coex. vap. sol. 



culated for the triple point and for the two points lying immediately 

 above and below it, the constants in the formula of Wrede-Rankine- 

 Keesom % ;>coex. = öfRK + ^RK ^~' + ^'RK ^~^ c^nd by differentiation 

 of this formula, the values of the differential coefficients. 

 In this way I found 

 dp\ 



^dJ /coex. vap. liij. 



As may be seen from these values there is a break in the usual 

 direction although very slight. 



From tlie observation already mentioned, that in the triple point 



= 0.08162; 1-^,^ =0.08623. 



^(11 /cuex. vap. sol. 



