  We derive source-free Maxwell-like equations in flat spacetime for any
helicity "j" by comparing the transformation properties of the 2(2j+1) states
that carry the manifestly covariant representations of the inhomogeneous
Lorentz group with the transformation properties of the two helicity "j" states
that carry the irreducible representations of this group. The set of
constraints so derived involves a pair of curl equations and a pair of
divergence equations. These reduce to the free-field Maxwell equations for j=1
and the analogous equations coupling the gravito-electric and the
gravito-magnetic fields for j=2.
