What did Henry Blair invent?
According to Maryland's African-American Heritage Web Site, Henry Blair actually received two U.S. patents. One in 1834 for his corn seed planter and a second in 1836 for a cotton planter.
It is assumed by historians that Blair was free, considering slaves could not receive patents. He could not read, however, and he signed his patent with an "x." He died in 1860.
For many years Blair was thought to have been the first black American to receive a patent. Later, research revealed Thomas L. Jennings received a patent in 1821 for the invention of the dry cleaning process.
—The Fact Monster