1142 
that overlapping of the distance spheres takes permanently place. 
For an arbitrary direction of motion we shall probably not have 
to go any higher than to a sufficient approach of 4 molecules, and 
this would justify the above given calculation of vgn = bum. We 
should have calculated this point when with decrease of v, the 
decrease of 6 is equal to it. Then zl. With values of v < vun all 
the molecules are not yet in contact; then tbere are still motions 
possible in this space, e.g. flowing of the substance or vibratory 
motions. But the motion which we call heat, has become impossible. 
Not until », is reached does every motion become impossible. The points 
of the b-curve, which [T have continued as far as in 5, above, have 
of course, no physical significance. The portion of the d-curve between 
Dim = 6, is then only to be considered as a parasitical branch. In 
the formula for the calculation of 5 this branch is probably also 
included. Accordingly I have entirely returned to the idea that the 
diminution of 6 is an apparent diminution of the volume of the 
molecules. | 
In these remarks I have touched upon several points which are 
of importance for the theoretical treatment of exceedingly condensed 
substances — without being able as yet to bring the investiga- 
tion to a close. That I mention them already now is because I hope it 
may stimulate others to give their attention to it, and that they 
may try their strength to bring the investigation to a close. The 
determination of vy, seems to me of special importance. 
Summary of the results obtained in this and previous communi- 
cations. 
If it was rigorously valid the law of the corresponding states 
would bave taught that all substances belonged to the same genus. 
This has proved not to be eatirely complete. Experience teaches that 
from this point of view, there are differences. All the substances, 
indeed, belong to the same genus, but there are different species. If 
the quantities characteristic of a substance are called the quantities 
jf, s, and r, they appear to differ. But these differences need not be 
considered as differences in 3 characteristic quantities, but they may 
be reduced to a single quantity. If this single quantity is called h, 
8 
then Soak s=—Vh and 2 is at least approximately equal to 
3 
—. When we try to find the significance of this characteristic 
Vh 
quantity, it will be found, as was a priori to be expected in what 
was left out of account in the derivation of the law of corresponding 
