  Two Lagrangian functions are used to construct geometric field theories. One
of these Lagrangians depends on the curvature of space, while the other depends
on curvature and torsion. It is shown that the theory constructed from the
first Lagrangian gives rise to pure gravity, while the theory constructed using
the second Lagrangian gives rise to both gravity and electromagnetism. The two
theories are constructed in a version of absolute parallelism geometry in which
both curvature and torsion are, simultaneously, non-vanishing. One single
geometric object, {\it W-tensor}, reflecting the properties of curvature and
torsion, is defined in this version and is used to construct the second theory.
The main conclusion is that a necessary condition for geometric representation
of electromagnetism is the presence of a non-vanishing torsion in the geometry
used.
