( 1397) 
and compared this value with the given one. The values of / occur 
on p. 142 and those for s on p. 60. KueNeN’s numerical values, 
however, have been chosen so as to belong to the equation: 
_il—m 
—- log,, « = f' —— 
m 
; a 64 
and so to yield the values of f meant in the formula ana oi 
KUENEN’s values must be divided by 0,4345. 
se f s calculated — s given 
lel 2.10 4.835 3.01 2.94 _(P)') 
Argon 2.18 5.02 3.08 2.67 
0, 2.50 5.757 3.36 349 (°?) 
Ethylene 2.75 6.55 3.99 3.42 
CO, 2 86 6.58 3.636 3.99 
Ethane 2.60 6 3.443 3.99 
CCl, 2.81 6.47 3.606 3.67 
Benzene 2.89 6.65 3.67 3.75 
Fluor-benzene 2.99 6.885 3.735 3.78 
Ether 3.01 6.93 8.75 3.81 
Esters 2.97—3.25 6.84—7.48 3.715—3.92 3.86—3.94 
First of all in this table the great difference in calculated and 
given value of s for Argon is very striking and this led me to 
inquire into the cause for this great difference. Now before the 
appearance of the Proceedings of the Royal Society of Febr. 1911 
I happened to look through the proof, and in this way I got 
acquainted with the observations of KAMERLINGH ONNEs and CROMMELIN, 
who give values for f' and s for Argon. There the value 3,283 is 
given for s, so still greater than in Kurnen’s list. But on the other 
hand /’ is much greater than is given above. If we take the value 
of f' at t= — 125,49, viz. 2.577, then f= 5.934, and we calculate 
s=3.41; -- again appreciably greater than 3,283. This led me to 
calculate the value of 7; itself from the data occurring in the cited 
communication. Specially because a sudden increase takes place in 
the given value of /’ near the critical temperature, which is not the 
case for other substances to the same extent. Between ¢ = — 140.80 
and ¢= — 125.49 KAMERLINGH Onn»s and CROMMELIN give four values 
for f' for ascending temperatures, viz. 2.415, 2.421, 2.457, and 
finally 2.577. The last value I have re-calculated — and I come 
1) The (?) mark is KUENEN’s. 
80 
Proceedings Royal Acad. Amsterdam. Vol. XIII. 
