the formula of PLANCK: 
De ee Sg ee nes eee 
/ 
PA 
so the chance that the velocity of a vibrating particle has the value 
s will be represented by: 
*/, ms* 
4 a mn Lt 1 Ap 
Ce ds where ms = — U =— — 
¥ 2 2 Av 
e G 1 
It is true that the formula (11) has been calculated with the aid 
of an equation of the form. (1) p. 1177 and that such an equation 
cannot hold good. But here a difference between the theory of PLANCK 
and the conception indicated in this communication comes to light, 
For if the quanta-hypothesis is right, the equation (1) cannot even 
approximately be fulfilled, and it is to be considered as the- 
merest chance if it leads to the exact value for U. According to 
the here developed conception however, the equation (1) cannot be 
rigorously satisfied, but it can hold with a rather high degree of 
approximation, and the sharpness of the lines of the spectra seems 
to indicate that this is really the case. For this reason it seems to 
me that we have reason to expect, that we can find the average 
kinetic evergy of rotating particles, or of particles describing paths 
disturbed by collisions, with the aid of the ordinary fundamental 
equations of classical mechanics and electromagnetics. For this 
purpose we have to investigate the motions which those particles 
would perform according to those equations in an electromagnetic 
field whose partition of energy is that of the normal spectrum. 
According to the quanta-hypothesis it would seem doubtful whether 
such a calculation would yield the right value for the velocity of 
the particles. 
These conclusions would not be justified, if it should appear that 
the equations of motion of the electrons cannot be approximately 
represented by equation (1). In this case we should have no reason 
to expect that the velocities of the vibrating particles are distributed 
according to Maxwerr’s law for the partition of the velocities. It 
seems probable to me that the normal prohability-curve will rather 
apply to the momenta than to the velocities. If the mass is constant 
we have no reason to make this difference, but in the case that 
