What does it mean
Thomas L. Jennings (New York 1791 – 1856) was a tailor and the first African-American to earn a patent in the United States; he invented a cleaning method called dry-scouring and patented it in 1821. Many people came out against an African-American being awarded a patent, but since he was a free man there was no way to prevent it. During that period, slaves could not be the legal owners of their ideas and inventions. He used the money from his invention to free the rest of his family and donate to causes in favour of abolishing slavery.