  The angular two-point correlation function between background QSOs and
foreground galaxies induced by gravitational lensing is derived. It is shown
that the shape of this correlation function depends sensitively on the spectrum
of the density fluctuations in the Universe, thus providing a possibility to
distinguish between different models for the spectrum. Using numerical
large-scale structure simulations, I estimate that the QSO-galaxy correlation
function can be measured from galaxy counts down to $\simeq21^{\rm
st}\ldots22^{\rm nd}$ magnitude in fields with radius $\la25'$ around
$50\ldots100$ QSOs with redshift $z\ge1$. Since the QSO-galaxy correlation
function is proportional to $(-a-1)b$, where $b$ is the biasing factor of
galaxy formation and $a$ is the effective slope of the QSO number counts, steep
number counts are favorable for this kind of analysis. I show that
$a=-4\ldots-5$ can be achieved with the 1-Jansky sample of radio-loud QSOs when
the double-waveband magnification bias is employed. Moreover, the
cross-correlation analysis allows to determine the galaxy-formation bias factor
$b$.
