  A general calculation for the distribution of non-uniform demagnetization
fields in paramagnetic bulk solids is described and the fields for various
sample geometries are calculated. Cones, ellipsoids, paraboloids and
hyperboloids with similar sample aspect ratios are considered. Significant
differences in their demagnetization fields are observed. The calculation shows
that the demagnetization field magnitudes decrease along the axis of symmetry
(along $z$) where an externally applied magnetic field is aligned, and increase
in the vicinity of the lateral surfaces with the largest field values found in
the cone and the narrowest field distributions found in the hyperboloid.
Application is made to the theoretical modeling of the $^{1}$H-NMR spectra of a
single crystal of field-induced superconductor $\lambda$-(BETS)$_{2}$FeCl$_{4}$
with a rectangular sample geometry, providing a good fit to the measured NMR
spectra. This calculation is also applicable to diamagnetic or ferromagnetic
materials in general.
