AAE 
state a separation takes place of the “kritische Räume” of the 
hydrogen atoms and the chlorine atoms inter se, the dissimilar atoms 
remaining bound. Hence the energy quantity /“must be the energy which 
prevails, when the four “kritische Raume” coincide, while the value of 
the entropy must take account of the volume of the coinciding Räume. 
When we consider that the difference of energy between the 
reacting substances and the transitional state is no more to be cal- 
culated aprioristically than any other chemical change of energy, 
and that as yet we have no means at our disposal either, to predict 
the volumes of the “kritische Raume” by the aid of the properties 
of the substances, it is clear that we cannot test the above conside- 
rations except by examining whether we can assign plausible values 
of the energy and the entropy to the transitional states to get into 
harmony with the known material of facts. It is true that NeRnst’s 
theorem of heat, in the form as it is conceived by PLanck, fixes 
the values of the entropy of solid substances at the absolute zero, 
so that the entropy constants: of the gases are brought in relation 
with the integration constants of the vapour pressure, but even if 
one is convinced of the validity of the theorem of heat, yet the 
imperfect knowledge of the specific heats presents too great a diffi- 
culty up to now to calculate entropies a priori. With regard to the 
transitional states such a calculation is a fortiori impossible, as the 
facts known to us indicate that these transitional states greatly vary 
for different reactions, and are e. g. greatly influenced by catalysers. 
When we now inquire into what the material of facts can teach 
us with regard to the transitional states, we will examine in the 
first place whether the energy in the transitional state is greater or 
smaller than in the initial or in the final state, or whether it perhaps 
lies between these two latter values. To answer this question [ will 
(to keep the considerations as simple as possible), consider a reac- 
tion in a rarefied gas mixture that completely takes place in one 
direction. In this case the second partial velocity has a negligibly 
small value compared with the first. The velocity of the reaction is 
then represented by: 
ee Oy, PL Ogee ee By 
If we now insert the value of mw, for the dilute gas-mixture, 
which according to our preceding paper may be represented by: 
7. 
Cy 
ey TS ven i Duy [od ee Par | 
Uy bie Pils, 21 | ES | me (3) 
+ RTD vylne, + RTZv, 
