 In his model the planet had a semi-major axis of ∼300 AU, and he based locations from clustering of the aphelion distances of periodic comets.In 1882, Forbes became manager of the British Electric Light Company, manufacturers of carbon filaments and arc lamps.He experimented with using carbon for the brushes in electric motors, rather than wire or gauze and in 1885 took out a patent for the "Improved Means for Establishing Electric Connection between Surfaces in Relative Motion Applicable to the Collectors of Dynamo Machines".