(402% } 
for argon, and the assumption was then justitied; we must, therefore 
put cq =O. But we have just found a value for A,, and, since 
K,= K,a*) it follows that 
Kasa = 3.283 and — ba = ay — 0.9027. 
From this we may conclude either that argon is an exception to 
Youne’s rule, or, as is not impossible, that its diameter is somewhat 
curved, in which case it would belong to the first group given by 
Youre. An accurate experimental research upon the diameter for 
argon would probably lead to important results bearing not only 
upon this point, but also upon the question of the value of the 
critical density of argon. 
For oxygen Marnias and K AMERLINGH ONNES ®) found 
hg dake, Ka 040, ei 
It appears, therefore, as if values of Asa in Youna’s criterion 
become smaller and smaller the lower the critical temperature of 
the substance. 
d. We can, in the meantime, say nothing definite about the function 
investigated by ReriNGANUM ®) and by Voeer®). An investigation of 
this point is, however, in progress. 
!) The subscript d in Asa is used to indicate the fact that the value of the 
eritical volume with which this number is calculated has been obtained from the 
diameter. Although the value here given for the critical virial quotient has been 
obtained fro:a a value of vj calculated from the isotherms, we have, nevertheless, 
assumed that we may write A4— Kya, seeing that probably the two values of 
vx obtained by the two different methods differ but little from each other. (See 
Comm. NO. 1182). 
2) Proc. Febr. 1911. Comm. No. 117. 
3) M. Retncanum, Diss. Göttingen 1899. Ann. d. Phys. (4). 18. 1008. 1905. 
Phys. Ztschr. 11. 735. 1910. 
') G. Voeer, Diss. Freiburg (Baden) 1910, Ztschr. f. phys. Chem. 73. 429. 1910. 
67 
Proceedings Royal Acad. Amsterdam. Vol. XIIL. 
