Benjamin Banneker

Benjamin Banneker, born as a free African American, became largely through self-education a prominent mathematician, astronomer, surveyor, and compiler and publisher of almanacs that combined both scientific information and social commentary. He is best known for helping Andrew Ellicott survey the original boundaries of the District of Columbia (1791), for publishing a series of popular annual almanacs (1792–1797), and for building a wooden clock (circa 1750s) modeled solely from a pocket watch lent by a wealthy acquaintance–the first wooden clock constructed in America that kept accurate time for more than fifty years.

In 1789, Banneker made astronomical calculations that enabled him to forecast successfully a solar eclipse. His estimate, made well in advance of the celestial event, improved upon predictions of better-known mathematicians and astronomers. His 1791 correspondence with then-Secretary of State Thomas Jefferson emphasized the injustice of slavery and sought Jefferson’s aid in bringing about better conditions for African Americans. In his last years, he published a treatise on bees, conducted a mathematical study on the cycle of the seventeen-year locust, and became a pamphleteer for the anti-slavery movement.