453 



(3). 1<^<10. 



In this region the formulae can probably only be used as rough 

 approximations. Curve /// in fig. 3 has been obtained by reducing 

 the observations for hydrogen and oxygen to carbon dioxide by 

 means of the law of corresponding states. The values given by /// 

 have been used in this range for calculating the corrections. The 

 results under I corr. and II corr. agree fairly well with each other. 

 The observations are, however, not sufficient to draw conclusions 

 with regard to the value of thermal molecular pressure in this 

 intermediate region. 



This region has, therefore, not been sufficiently studied as yet 

 and new measurements in this range would be of the greatest 

 interest. 



In table II column 5 under "calc. according to Nernst" the pres- 

 sures are given calculated by the aid of Nernst's formula. In the 

 former paper use was made of the formula with the values of the 

 constants found by Falck ^), viz. 



6000 1 0.00913 



logü = .- + 1.75 log T T + 3.1700 . (/) 



*'^ 4.571 T ^ "" 4.571 ^ ^ ^ 



In order to obtain a satisfactory agreement at higher pressures 

 the constants had to be slightly modified as follows 



6007.9 1 , 0.009008 



logü= .-f 1.751ogr r+ 3.1700 . (//). 



"^ 4.571 T "^ 4.57 L ^ ^ ^ 



p is here expressed in atmospheres. 



The coefficient of log T and the chemical constant are unchanged, 

 and the other two constants have been only slightly altered. This 

 alteration can have no influence on Falck's theoretical deductions. 

 The very low vapour pressures which we measured before with 

 the absolute manometer are also unchanged, as the term proportio- 

 nal to T has but little influence in that region. In that case 

 Nermst's formula reduces to the vapour pressure formula according to 

 Kirchhoff-Rankine-Dupré *). 



It can hardly be expected that formula // should give good 

 agreement at temperatures much higher than those given in table 

 II. At higher temperatures Falck finds greater deviations which, 

 however, he considers to be due to errors of observation. I have 



1) F. Falck : Phys. Z. S. 1908, p. 433. 



2) H. Kamerlingh Onnes und W. H. Keesom: Die Zustandsgleichung Leiden 

 Gomm. Suppl. N". 23 pag. 300. 



