  We analyze a time sequence of Inter-Network (IN) magnetograms observed at the
solar disk center. Speckle reconstruction techniques provide a good spatial
resolution (0.5" cutoff frequency) yet maintaining a fair sensitivity (some
20G). Patches with signal above noise cover 60% of the observed area, most of
which corresponds to intergranular lanes. The large surface covered by signal
renders a mean unsigned magnetic flux density between 17G and 21G (1G \equiv
1Mx cm$^{-2}$). The difference depends on the spectral line used to generate
the magnetograms (Fe I 6302 or Fe I 6301). Such systematic difference can be
understood if the magnetic structures producing the polarization have intrinsic
field strengths exceeding 1 kG, and consequently, occupying only a very small
fraction of the surface (some 2%). We observe both, magnetic signals changing
in time scales smaller than 1 min, and a persistent pattern lasting longer than
the duration of the sequence (17 min). The pattern resembles a network with a
spatial scale between 5 and 10 arcsec, which we identify as the
mesogranulation. The strong dependence of the polarization signals on spatial
resolution and sensitivity suggests that much quiet Sun magnetic flux still
remains undetected.
