  We consider the electromagnetic resolution of gravitational field. We show
that under the duality transformation, in which active and passive electric
parts of the Riemann curvature are interchanged, a fluid spacetime in comoving
coordinates remains invariant in its character with density and pressure
transforming, while energy flux and anisotropic pressure remaining unaltered.
Further if fluid admits a barotropic equation of state, $p = (\gamma - 1) \rho$
where $1 \leq \gamma \leq 2$, which will transform to $p = (\frac{2 \gamma}{3
\gamma - 2} - 1) \rho$. Clearly the stiff fluid and dust are dual to each-other
while $\rho + 3 p =0$, will go to flat spacetime. However the n $(\rho - 3 p =
0)$ and the deSitter $(\rho + p = 0$) universes ar e self-dual.
