  It has been shown that t00 component of the energy-momentum pseudotensor in
the case of cylindrically symmetrical static gravitational field cannot be
interpreted as energy density of the gravitation field. An approach has been
suggested allows one to express the energy density of the cylindrically or
spherically symmetrical static gravitation field in terms of the metric tensor
components. The approach based on the consideration of the process of
isothermal compression of a cylinder consisted of incoherent matter.
