  On the basis of a simultaneous description of the isoscalar s-wave channel of
the $\pi\pi$ scattering (from the threshold up to 1.9 GeV) and of the
$\pi\pi\to K\bar{K}$ process (from the threshold to $\sim$ 1.4 GeV) in the
model-independent approach, a confirmation of the $\sigma$-meson at $\sim$ 660
MeV and an indication for the glueball nature of the $f_0(1500)$ state are
obtained.
