246 



The tempei-atnre on the KEJA-iN-scale ^) corresponding to these 

 vapour pressures are taken from measurements by Kam krlingh Onnes 

 and Keesom, not yet published. Their results have not been definitely 

 calculated, but the small corrections which may be as yet required 

 are of no importance for the object of this paper. 



For the method of calcuhiting the volumes we may refer to the 

 paj)er on tlie diameter of argon quoted above. 



The results are contained in the table. It also gives the densities 

 calculated by the quadratic formula 



Or ;• = « + hT -\- CT"^ 

 s I iiq ' ' 



with the following values of the constants: 



a = + 0.084404 

 6 r=i — 0.0002230 

 c — — 0.00002183 

 made to fit the readings at — 258°.27, — 255°. 99 and the boiling 

 point. 



The deviations from this formula will be seen to be very small; 

 they are witliin the limits of accuracy of the observations, except 

 possibly at the highest temperature. It may be added, that the density 

 at the boiling point was not directly observed, but was calculated 

 from the neighbouring observations.- 



The first column contains the number of the observation, the 

 second the temperature below 0° C, on the KELviN-scale, the third 

 the density observed referred to the density of water at 4° C, the 



^) The corrections for the reduction of the hydrogen-scale to the KELViN-scale 

 are given by H. Kamerlingh Oknes and W. J. de Haas, Proc. Sept. 1912. 

 Gomm. NO. 127c. 



