  The equilibrium shape of liquid drops on elastic substrates is determined by
minimising elastic and capillary free energies, focusing on thick
incompressible substrates. The problem is governed by three length scales: the
size of the drop $R$, the molecular size $a$, and the ratio of surface tension
to elastic modulus $\gamma/E$. We show that the contact angles undergo two
transitions upon changing the substrates from rigid to soft. The microscopic
wetting angles deviate from Young's law when $\gamma/Ea \gg 1$, while the
apparent macroscopic angle only changes in the very soft limit $\gamma/ER \gg
1$. The elastic deformations are worked out in the simplifying case where the
solid surface energy is assumed constant. The total free energy turns out lower
on softer substrates, consistent with recent experiments.
