Benjamin Banneker

Benjamin Banneker’s Contribution to Science

Benjamin Banneker was a self-educated African American scientist of the late eighteenth century. He lived in Baltimore County, on land in Catonsville that is now preserved as a park and museum (the Benjamin Banneker Historical Park and Museum) administered by the Baltimore County Department of Recreation and Parks and supported by the Friends of the Benjamin Banneker Historical Park and Museum. The Park and Museum has an active education program designed to teach about Banneker’s life and accomplishments.

Banneker is best known for two important scientific feats—his almanacs and his technical support during the survey of the boundary of the Federal City, present day Washington, D.C. With little formal training he learned the mathematical calculations needed to predict the positions of the Sun, Moon and planets for the last decade of the 18th century. These positions were recorded in a time ordered table, an ephemeris, and published in six annual almanacs in the 1790s which were wildly popular throughout the Chesapeake region. Farmers and sea fearers alike depended on Banneker’s forecasts of celestial events throughout the year to determine the best time to plant and harvest crops and forecast tides.

Banneker’s mechanical genius emerged early in his life and is best exemplified in his construction of a wooden-geared clock, based on his observations of a small pocket watch. This remarkable accomplishment and technical prowess set him apart and brought him in contact with other local scientists of his day. One of those scientists was Andrew Ellicott, a neighbor in nearby Ellicott’s Mills, who was commissioned around 1790 by the leaders of our young nation to survey the boundary line in the wilderness for a city that was to become our nation’s capital.

Banneker’s familiarity with the movements of celestial bodies and cutting-edge scientific instrumentation qualified him to participate in the survey. His job was to observe celestial events in the night sky, maintain the finicky celestial clock under wilderness conditions, and carefully record the time of certain celestial events in the night and daytime sky. The times and the observations were used to determine latitude and longitude, the precise locations needed for an accurate map. Even today, few understand or appreciate the complexity of the derivation of these critically important values. The fact that Banneker was a self-taught African American, the son and grandson of freed slaves from Africa, living at a time of great racial discrimination, makes his story all the more compelling and inspiring.

Banneker’s contribution to mathematics, science, and our nation’s history is told at the Benjamin Banneker Historical Park and Museum. The small museum contains professionally-designed exhibits relating to Banneker’s fascinating family story, his life as a farmer/naturalist and his scientific and social accomplishments. His way of life is interpreted in our replica cabin, gardens, and orchard on the 142 acre park property.