In 1874, Latimer along with Charles W. Brown patented an improved toilet system for railroad cars called the Water Closet for Railroad Cars. In 1876, Alexander Graham Bell employed Latimer, to draft the necessary drawings required to receive a patent for Bell's telephone. Latimer received a patent in January 1881 for the 'Process of Manufacturing Carbons', an improved method for the production of carbon filaments used in light bulbs. The Edison Electric Light Company in New York City hired Latimer in 1884, as a draftsman and an expert witness in patent litigation on electric lights. Latimer is credited with an improved process for creating a carbon filament at this time, which was an improvement on Thomas Edison's original paper filament, which would burn out quickly.