883 
volume is therefore 38,2.10°°*. If in this shortest distance we still 
assume approximate cubie distribution ') of the molecules, then s, 
becomes 5 3,37 .10~*, which agrees very well with the just cal- 
culated upper limit ’). 
We may therefore assume for argon s, = 3,5 . 10” cm. 
PERRIN gives for this (Conseil Solvay, German edition, p. 154), the 
somewhat too low value 2,7 .10 *, calculated from the length of path. 
For Hydrogen we tind 0,086 (Dewar) for the density at the melting 
paints). Hence. s° << (2,0152:: 0,086) .:6.1029) “ors <= S81. . 10-24 
Sed. 10% 
The value of 5, at H, being only known by approximation, no 
lower limit can be given. The value of 6, calculated by me before 
(These Proc. of April 24,1903) by means of VAN Der WAALS’ equation 
of state of the molecule is not suitable for this purpose. I found 
then namely 6, almost independent of the temperature, on the other 
hand 5, increasing with 7’, which is not probable. If for 5, the value 
0,000917, found before, is assumed, we find about 0,00076 for 0, 
with 6,:6,=1,2, hence 5,°S (0,00076 22412): 6.10235 28,3. 10-24, 
ors, = 3,00 10-2. 
[We once more draw attention to this, that if we had put = 4m 
according to the current assumption, and 6,= + 2m according to 
the theory of the apparent diminution of 6, we had found a much 
too small value for the lower limit}. 
For the present we can therefore assume s, = + 3,2.10 8 for H,. 
The value 4. 10-8, calculated from unknown data, which I found 
given somewhere, is therefore slightly too great. 
1) I. e. that even at the greatest density the molecules ‘do not occupy a smaller 
volume than S93. Only on the supposition of perfect spherical form, and the entire 
lack of impenetrable spheres of influence (see § 1) could it be assumed that a 
smaller minimum volume than s,° were possible. This, however, seems a physical 
impossibility to me, and — like the assumption of an apparent «iminution of 0 
in consequence of the partial overlapping of the distance spheres — only a mathe- 
matical fiction. Also the existence of crystal nets seems to plead strongly against 
the assumption of a denser accumulation than corresponds with s,% It might 
sooner lead us to the opposite conclusion. 
2) The sign of inequality > namely refers to the possibility that the molecules 
can occupy a somewhat smaller volume than 589°. 
3) To my regret I have no tabular works as the latest edition of Lanpotr und 
Bornstein, Recueil de constantes physiques, and others at my disposal, so that 
I had to be content with this slightly antiquated value of Dewar. I do not know 
any clear summary of the constants determined in the Leiden Laboratory for 
different substances. Neither in KAMERLINGH Onnes and Keesom’s book on the equation 
of state, nor in that of Kuenen did | find, except incidentally, numerical values 
of experimentally determined constants. 
