( 310 ) 
radiation” is, that we can aseribe a continuous existence to the 
entropy: when a body loses entropy by means of radiation and 
ancther gains entropy, we need not say, that in one place at least 
as much is created, as is lost in another place, but that the entropy has 
moved continuously through space from one place to another. The 
question about the localization of the entropy is, however, not of so 
much importance, as that about the localization of the energy. The 
constancy of this second quantity induces us to think of an identical 
continuance of existence, so that we postulate a perfectly continuous 
way of moving. This is not the case with the entropy and as the 
entropy of a point depends on the condition of the points round it, 
the entropy of a molecule may be modified by modifying its sur- 
roundings, there being no question of a continuous propagation. 
For if we assume the formula of BOLTZMANN: 
H = | Flog (F) do 
the amount which every molecule contributes to the entropy is 
—log(F’), as — H represents the entropy. This quantity is changed 
momentaneously for every molecule of the group /, when one or 
more molecules are added to that group, there being no question of 
propagation. It is remarkable that if the entropy in a volume element 
increases in consequence of shocks, the amount with which the 
entropy increases must be ascribed exclusively to the molecules 
which have collided. For in the quantity 4/ both F and log(/) change. 
The change may be represented by: 
Ik Flog (£) do + |E dlog (£) da. 
The first term is the increase of the entropy of the molecules 
which have collided, the second term that of the other molecules. 
The second term, however, appears to be 0, for: 
1 
[Pateg Mao fr arion dF do. 
This represents the change in the total number of molecules. This 
number is however, not changed by collisions, and the second term 
is 01). If however, the entropy of the volume elements as a whole 
1) See BOLTZMANN, Vorlesungen über Gastheorie, Iste Theil p. 35, 
