  We report and discuss the first neutron reflection measurements from the free
surface of normal and superfluid 4He and of liquid 3He-4He mixture. In case of
liquid 4He the surface roughness is different above and below the lambda
transition, being smoother in the superfluid state. For the superfluid, we also
observe the formation of a surface layer ~200 A thick which has a subtly
different neutron scattering cross-section. The results can be interpreted as
an enhancement of Bose-Einstein condensate fraction close to the helium
surface. We find that the addition of 3He isotopic impurities leads to the
formation of Andreev levels at low temperatures.
