  The energy-level scheme and wave functions of the titanium ions in
LaTiO$_{3}$ are calculated using crystal-field theory and spin-orbit coupling.
The theoretically derived temperature dependence and anisotropy of the magnetic
susceptibility agree well with experimental data obtained in an untwinned
single crystal. The refined fitting procedure reveals an almost isotropic
molecular field and a temperature dependence of the van Vleck susceptibility.
The charge distribution of the 3d--electron on the Ti positions and the
principle values of the quadrupole moments are derived and agree with NMR data
and recent measurements of orbital momentum $<l>$ and crystal-field splitting.
The low value of the ordered moment in the antiferromagnetic phase is
discussed.
