  There is the Gibbs theorem in thermodynamics, according to which the entropy
of the mixture of ideal gases is equal to the sum of the entropies of the
components of the mixture. J. W. Gibbs proved this by a mathematical derivation
from the beginnings of thermodynamics and the laws of ideal gases, in
particular Dalton's law. This message shows that this proof is mathematically
incorrect. It is also shown that the Gibbs theorem cannot be derived
mathematically from Dalton's law.
