767 



used or another). Tlie value 580.10—^ given by K. Onnes seems 

 too low. From his experiments even the still lower value 566 is 

 calculated, whereas from those of Amagat 619 would follow. The 

 mean of the two values, viz. 593, will not be far from the truth. 



Also for 100° C. the |)robal)ly coi-)-ect value, viz. 934, will 

 probably lie near the mean value of the results of the two series of 

 experiments (this mean of 862 and 997 is 930). 



The advantage of the exponential expression for f{T) over the 

 other with l—2a\^T-\-Q{Q.. is apparent especially in the last three 

 values of 10^^, calculated from the experiments for the unsaturated 

 i:/,- vapour below T^, which values range from — 480 to about 

 — 630. The latter expression would give for this the values — 403 

 to — 429, which increase but little and ai-e much too low, while 

 the exponential formula yields thé better values from — 470 to — 570. 

 But here possibly also the effect of quanta comes into play. 



Exceedingly instructive is also the last column, in which the 

 values of lO'/i (found;, divided by TiTb — 1 are given. If namely 

 the relation h,,:a is really constant, as we have reason to suppose 

 in virtue of what was stated in § III and IV, the quotient 

 B:{7'ITb — 1) indicates the value of a at any temperature accord- 

 ing to (14). It is then seen still more clearly that at 0° and 100° 

 Amagat's observations yield too high values, those of K. Onnks too 

 low values (in connection with the fixed value at 20° C). And 

 further that the ^-values at — 183° and — 217° calculated from 

 K. O.'s observations do not at all fit in with the others, as they 

 yield too high values for \0^a, namely 517 and 506, which values 

 would be higher than those at T^, which is impossible. 



In the next paper I shall give something about the theoretical 

 derivation of the exponential formula, also in connection with the 

 earlier views of Reinganum and myself, and of the later ones of 

 Kresom in this respect, followed by the drawing up of an entirely 

 new theory on the virial of attraction and collision. Further the 

 influence of the volume will be discussed, and also the liquid volu- 

 mes in the region of saturation; then the calculation of the values 

 of the virial coefficient B from Amagat's and K. OnnesI material, 

 the results of which have already been mentioned in the above 

 table II. 



Fojitaniveni, 1916 — 1917. {To he continued). 



55* 



