By the early 1820s, Thomas L. Jennings owned one of the largest and best tailoring houses in the city. He didn’t like seeing his fine suits ruined, so he began experimenting with chemicals to clean fabrics without damaging them. On March 3, 1821, he became the first African American to receive a US patent. It was for “dry scouring” a forerunner of today’s dry cleaning.
Prior to 1836, the US didn’t number patents. After a fire destroyed the patent house that year, it assigned numbers to all patents registered between 1793 and 1836. These are known as the “X” patents. Jennings’s patent papers were lost in the fire, and recorded as patent 3306X. Other lost x-patents included Eli Whitney’s Cotton Gin, Samuel Colt’s improved firearms, and Samuel Morey’s combustion engine.
Despite all the limitations put upon them, slaves also did their share of inventing, for which their owners wanted compensation. Slaveholder Oscar Stewart tried to patent a “cotton scraper” invented by a slave known as Ned. Denied his patent, Stewart sold the product without it. Benjamin Montgomery invented a steam-driven propeller to replace riverboat paddlewheels. His owner happened to be Jefferson Davis’s brother.
In 1857, the US government ruled that inventions by slaves weren’t patent protected. Confederate president Jefferson Davis made sure the patent law was changed in his new government. In 2015, Thomas L. Jennings was elected to the National Inventors Hall of Fame in Alexandria, Virginia.
Blodgett’s Hotel housed the US Patent Office from 1810 until it burned down in 1836.