Correcting Identities: Image, This is Not Nathaniel Alexander.
This is Lewis Howard Latimer. (September 4, 1848 – December 11, 1928).

While both were Black inventors, there is NO verified image of Nathaniel Alexander to date.
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Lewis Howard Latimer was born in Chelsea, Massachusetts, on September 4, 1848, the youngest of the four children of Rebecca Latimer (1823–1910) and George Latimer (1818–1897).

He was an American inventor and patent draftsman. His inventions included an evaporative air conditioner, an improved process for manufacturing carbon filaments for light bulbs, and an improved toilet system for railroad cars.

In 1884, he joined the Edison Electric Light Company where he worked as a draftsman. The Lewis H. Latimer House, his landmarked former residence, is located near the Latimer Projects at 34-41 137th Street in Flushing, Queens, New York City.

Before Lewis was born, his mother and father escaped from slavery in Virginia and fled to Chelsea, Massachusetts on October 4, 1842. The day they arrived in Boston, George was recognized by a colleague of his former slave owner and was arrested a few days later, on October 20, 1842.

George's trial received great notoriety; he was represented by Frederick Douglass and William Lloyd Garrison. He was eventually able to purchase his freedom and live with his family in Chelsea, Massachusetts.

When Latimer was young he spent time (before his father left) helping his father in his barbershop. Lewis Latimer also spent time at night hanging wallpaper with his father.

When Latimer was 10, his mother decided to split the family after the Dred Scott case ruled individual slaves needed to prove they had the consent of their owner to legally become free; many slaves at the time such as the Latimers had lived free by escaping into free states and becoming state citizens who often would not be sent back to their owners if apprehended by interstate slave catchers.

This caused Lewis's father, George Latimer, to flee for his family's safety because he had nothing to prove he was free from enslavement. So, he fled to protect his family.

After his father had to flee and his mother had to split the family, Lewis and his brothers were sent to a farm school, and his sisters were sent to stay with a family friend.

Lewis Howard Latimer joined the U.S. Navy at the age of 16 on September 16, 1864, and served as a Landsman on the USS Massasoit. After receiving an honorable discharge from the U.S. Navy on July 3, 1865, he gained employment as an office boy with a patent law firm, Crosby Halstead and Gould, with a $3.00 per week salary. He learned how to use a set square, ruler, and other drafting tools. Later, after his boss recognized his talent for sketching patent drawings, Latimer was promoted to the position of head draftsman earning $20.00 a week by 1872 ($438.59 today).

Lewis H. Latimer married Mary Wilson Lewis on November 15, 1873, in Fall River, Massachusetts. Mary was born in Providence, Rhode Island, the daughter of Louisa M. and William Lewis. The couple had two daughters, Emma Jeanette (1883–1978) and Louise Rebecca (1890–1963). Jeanette married Gerald Fitzherbert Norman, the first black person hired as a high school teacher in the New York City public school system, and had two children: Winifred Latimer Norman (1914–2014), a social worker who served as the guardian of her grandfather's legacy, and Gerald Latimer Norman (1911–1990), who became an administrative law judge.

In 1879, Latimer and his wife, Mary, moved to Bridgeport, Connecticut, along with his mother, Rebecca, and his brother, William. They settled in a neighborhood called "Little Liberia," which had been established in the early 19th century by free blacks. (The landmark Mary and Eliza Freeman Houses are the last surviving buildings on their original foundations of this community.)

Other family members already living there were his brother, George A. Latimer, his wife, Jane, his sister, Margaret, and her husband, Augustus T. Hawley, and their children. Mary died in Bridgeport in 1924.

Source: Wikipedia
Image: Latimer in 1882