  The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250
GeV/c are analysed in the framework of the hydrodynamical model of
three-dimensionally expanding cylindrically symmetric finite systems.
  A satisfactory description of experimental data is achieved.
  The data favour the pattern according to which the hadron matter undergoes
predominantly longitudinal expansion and non-relativistic transverse expansion
with mean transverse velocity <u_t> = 0.20(7), and is characterized by a large
temperature inhomogeneity in the transverse direction: the extracted freeze-out
temperature at the center of the tube and at the transverse rms radius are
140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal)
space-time rapidity distribution of the pion source is found to be Delta eta =
1.36(2).
  Combining this estimate with results of the Bose-Einstein correlation
analysis in the same experiment, one extracts a mean freeze-out time of the
source of <tau_f> = 1.4(1) fm/c and its transverse geometrical rms radius, R_G
(rms)=1.2(2) fm.
