  Using two simple and robust inputs to constrain the mixing matrix of the
isosinglet scalar mesons $f_0(1710)$, $f_0(1500)$, $f_0(1370)$, we have shown
that in the SU(3) symmetry limit, $f_0(1500)$ becomes a pure SU(3) octet and is
degenerate with $a_0(1450)$, while $f_0(1370)$ is mainly an SU(3) singlet with
a slight mixing with the scalar glueball which is the primary component of
$f_0(1710)$. These features remain essentially unchanged even when SU(3)
breaking is taken into account. We have deduced the mass of the pseudoscalar
glueball $G$ from an $\eta$-$\eta'$-$G$ mixing formalism based on the anomalous
Ward identity for transition matrix elements. With the inputs from the recent
KLOE experiment, we find a solution for the pseudoscalar glueball mass around
$(1.4\pm 0.1)$ GeV. This affirms that $\eta(1405)$, having a large production
rate in the radiative $J/\psi$ decay and not seen in $\gamma\gamma$ reactions,
is indeed a leading candidate for the pseudoscalar glueball. It is much lower
than the results from quenched lattice QCD ($>2.0$ GeV).
