  A one-dimensional harmonic chain model is used to study the non-equilibrium
distribution function of phonons induced by a heat flux across the interface
between two crystals. Conditions are derived which govern the matching of
distribution functions on both sides of the interface. A generalization of the
Enskog--Chapman method for calculating the Kapitza conductance is introduced. A
precise relation is obtained under some simplifications.
  This version contains improved translation, modernized notation, and corrects
one mistake, that does not affect the final formulae.
