In 1874, along with W.C. Brown, Latimer co-invented an improved of a train water closet, a bathroom compartment for railroad trains. Two years later, Latimer would play a part in one of the world’s most important inventions.

In 1876, Latimer was sought out as a draftsman by a teacher for deaf children. The teacher had created a device and wanted Lewis to draft the drawing necessary for a patent application. The teacher was Alexander Graham Bell and the device was the telephone. Working late into the night, Latimer worked hard to finish the patent application, which was submitted on February 14, 1876, just hours before another application was submitted by Elisha Gray for a similar device.

In 1880, after moving to Bridgeport, Connecticut, Latimer was hired as the assistant manager and draftsman for U.S. Electric Lighting Company owned by Hiram Maxim. Maxim was the chief rival to Thomas Edison, the man who invented the electric light bulb. The light was composed of a glass bulb which surrounded a carbon wire filament, generally made of bamboo, paper or thread. When the filament was burned inside of the bulb (which contained almost no air), it became so hot that it actually glowed.

Thus by passing electricity into the bulb, Edison had been able to cause the glowing bright light to emanate within a room. Before this time most lighting was delivered either through candles or through gas lamps or kerosene lanterns. Maxim greatly desired to improve on Edison’s light bulb and focused on the main weakness of Edison’s bulb – their short life span (generally only a few days.) Latimer set out to make a longer lasting bulb.

Latimer devised a way of encasing the filament within an cardboard envelope which prevented the carbon from breaking and thereby provided a much longer life to the bulb and hence made the bulbs less expensive and more efficient. This enabled electric lighting to be installed within homes and throughout streets.

Latimer’s abilities in electric lighting became well known and soon he was sought after to continue to improve on incandescent lighting as well as arc lighting. Eventually, as more major cities began wiring their streets for electric lighting, Latimer was dispatched to lead the planning team. He helped to install the first electric plants in Philadelphia, New York City and Montreal and oversaw the installation of lighting in railroad stations, government building and major thoroughfares in Canada, New England and London.

In 1890, Latimer, having been hired by Thomas Edison, began working in the legal department of Edison Electric Light Company, serving as the chief draftsman and patent expert. In this capacity he drafted drawings and documents related to Edison patents, inspected plants in search of infringers of Edison’s patents, conducted patent searches and testified in court proceeding on Edison’s behalf. Later that year wrote the worlds most thorough book on electric lighting, “Incandescent Electric Lighting: A Practical Description of the Edison System.” Lewis was named one of the charter members of the Edison pioneer, a distinguished group of people deemed responsible for creating the electrical industry. The Edison Electric Lighting would eventually evolve into what is now known as the General Electric Company.