In the years before the outbreak of the Civil War…the future president of the Confederacy, Jefferson Davis, filed a patent claim on an improved riverboat propeller with the U.S. Patent Office. The novel design promised both increased efficiency and improved maneuverability compared with the paddlewheels then favored by most river steamships. His claim, however, was summarily denied. Davis is remembered for many things, though not for being an accomplished inventor, and for good reason: The improved propeller wasn’t his to patent. Instead, it was the work of Benjamin Montgomery, a slave on the plantation of Davis’s brother Joseph.