A linear polonium source of about 2 millicuries strength is surrounded by beryllium contained in a brass cylinder coated with a layer of paraffin. This assembly is mounted on the piston in the center of a large automatic Wilson cloud chamber, in which the tracks due to protons projected from the paraffin layer by the neutrons are photographed. The angle between the proton track and its associated radius is measured. Corrections for scattering volume and effective solid angle of the cloud chamber are applied. On plotting the corrected number of proton tracks against the angle of projection a sharp maximum is found at 0°. The bearing of this distribution on the structure of the neutron is discussed.