  The surface free energy, or surface tension, of a liquid interface gives rise
to a pressure jump when the interface is curved. Here we show that a similar
capillary pressure arises at the interface of soft solids. We present
experimental evidence that immersion of a thin elastomeric wire into a liquid
induces a substantial elastic compression due to the solid capillary pressure
at the bottom. We quantitatively determine the effective surface tension from
the elastic displacement field, and find a value comparable to the liquid-vapor
surface tension. Most importantly, these results also reveal the way the liquid
pulls on the solid close to the contact line: the capillary force is not
oriented along the liquid-air interface, nor perpendicularly to the solid
surface, as previously hypothesized, but towards the interior of the liquid.
