  The simultaneous study of deformation and heat transmission in a bar was
ignored for about 150 years.
  The traditional Fourier equation just allows to study the evolution of
temperature in a undeformable bar. The search for its relativistic variant is a
task which must fail because in Relativity there are no undeformable bars.
Rigid bodies, in the sense as rigid as possible, are deformables.
  In this work we show how to write in Relativity the system of equations
necessary to study simultaneously deformation and temperature evolution along a
rigid bar.
