  Simple, self-similar, analytic solutions of 1 + 1 dimensional relativistic
hydrodynamics are presented, generalizing the Hwa - Bjorken boost-invariant
solution to inhomogeneous rapidity distributions. These solutions are
generalized also to 1 + 3 dimensional, cylindrically symmetric firetubes,
corresponding to central collisions of heavy ions at relativistic bombarding
energies.
