Benjamin Bradley astounded his colleagues and the owner by constructing a steam engine out of a gun barrel, steel, and pewter, among other materials.
Awed by his brilliance, his owner arranged for him to serve as an apprentice at the Naval Academy’s Department of Natural and Experimental Philosophy in Annapolis, Maryland. Bradley had shown an interest in mechanical engineering as early as the age of 16.
He showed great promise at the Naval Academy and was given the opportunity to help with science experiments involving chemical gases. While at the Academy, he built a steam engine and sold it to the “Midshipmen”, according to the African-American Registry. He used the proceeds and money he saved from his academy service to build a larger steam that could propel “the first sloop-of-war (a small warship carrying guns on one deck) at a rate of 16 knots per hour,” according to BlackPast.
Bradley was well aware that his status as a slave would make it impossible for him to patent his invention under state law. So he sold the model engine to a Naval Academy colleague and went on to build the first steam engine capable of powering a warship. He sold this invention and used the proceeds including monies given to him by professors at the academy to purchase his freedom at $1000.
According to Maryland State Manumission, Bradley was freed from his owner, John T. Hammond, on September 30, 1859, in Anne Arundel, Maryland. When the Naval Academy relocated to Newport, Rhode Island during the American Civil War, he was hired as an instructor by the Philosophical Department. He began working as a free man for Prof. A.W. Smith.
Bradley devoted his efforts to the construction of small steam engines, fulfilling his ambition of becoming a mechanical guru. He was recognized for designing and building a “miniature steam engine and boiler about 6-fly power.”
Bradley, who was born in Anne Arundel County, Maryland, in March 1836, learned to read and write from his owner’s children. During his formative years, he worked at a printing company. In 1900, census officials recorded him as 64 years old and living in Mashpee, Massachusetts, with a job description of philosophical lecturer. According to the census, he was married to Gertrude Boardley for 19 years and they had three children. Bradley died in 1904 and was laid to rest in the Mashpee Town Cemetery in Massachusetts.