  We study the non-equilibrium regime of the Kondo effect in a quantum dot
laterally coupled to a narrow wire. We observe a split Kondo resonance when a
finite bias voltage is imposed across the wire. The splitting is attributed to
the creation of a double-step Fermi distribution function in the wire. Kondo
correlations are strongly suppressed when the voltage across the wire exceeds
the Kondo temperature. A perpendicular magnetic field enables us to selectively
control the coupling between the dot and the two Fermi seas in the wire.
Already at fields of order 0.1 T only the Kondo resonance associated with the
strongly coupled reservoir survives.
