1121 
These equations enable us to calculate the differences of the required 
substitution energies from measurements of the velocity, at least for 
so far as they have been performed at different temperatures. 
If we now also apply equation 2, we get: 
BE Sin Sets 
ln as EE DR 4 By —B, . Fy a 4 5 e (4a) 
pe ae cap cement: te oe EAB) 
ky RT satan 
In fn EE Be ia an (ey 
kp RT Pp m 
With respect to the constants B from the equation 4 we know 
that each of them consists of the required entropy difference and of 
constants which do not depend on the nature of the reacting sub- 
stances. These Jatter disappear therefore in equation 4, where always 
differences between two 4-values occur, so that the value B,—B, 
of equation 4a can be replaced by »— , and just so for the 
other equations. 
So we see that the difference of the substitution energies and 
entropies can be directly calculated for these reactions from the 
experimental determinations. The accuracy with which these calcu- 
Jations can be carried out, is of course determined by the value of 
the errors of observation. 
When I applied equations + to the data, it soon appeared that 
the values for a, — 1, ete. in general possess small. amounts, and 
sometimes differ very little from zero. | have therefore examined 
whether it is possible to account for the observations only. by a 
difference of energy, lence by assuming that the difference in sub- 
stitution-entropy would be zero for the different hydrogen atoms. 
Mathematically this comes to this that every substitution might be 
represented by the aid of one constant, which would then have the 
meaning of the difference in substitution-energy. On this hypothesis 
the equations 4 are transformed into: 
he Te ak Er 
In 2 = RT mest NS seat (OM) 
k CS a 
ln = EE IE 5 . ° ° . ° ° . ° (56) 
D : 
i ft, JE a 
l SS 5e 
n a RT (50) 
73* 
