Benjamin Banneker Biography

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Encyclopedia of World Biography on Benjamin Banneker

Benjamin Banneker (1731-1806), an African American mathematician and amateur astronomer, calculated ephemerides for almanacs for the years 1792 through 1797 that were widely distributed.

On Nov. 9, 1731, Benjamin Banneker was born in Baltimore County, Md. He was the son of an African slave named Robert, who had bought his own freedom, and of Mary Banneky, who was the daughter of an Englishwoman and a free African slave. Benjamin lived on his father's farm and attended a nearby Quaker country school for several seasons. He received no further formal education but enjoyed reading and taught himself literature, history, and mathematics. He worked as a tobacco planter for most of his life.

In 1761, at the age of 30, Banneker constructed a striking wooden clock without having seen a clock before that time, although he had examined a pocket watch. The clock operated successfully until the time of his death.

At the age of 58 Banneker became interested in astronomy through the influence of a neighbor, George Ellicott, who lent him several books on astronomy as well as a telescope and drafting instruments. Without further guidance or assistance, Banneker taught himself the science of astronomy; he made projections for solar and lunar eclipses and computed ephemerides (tables of the locations of celestial bodies) for an almanac.

In February 1791 Maj. Andrew Ellicott was appointed to survey the 10-mile square of the Federal Territory for a new national capital, and Banneker worked in the field as his scientific assistant for several months. After the base lines and boundaries had been established and Banneker had returned home, he prepared an ephemeris for the following year, which was published in Baltimore in Benjamin Banneker's Pennsylvania, Delaware, Maryland and Virginia Almanack and Ephemeris, for the Year of Our Lord, 1792; Being Bissextile, or Leap-Year, and the Sixteenth Year of American Independence, which commenced July 4, 1776.

Banneker forwarded a manuscript copy of his calculations to Thomas Jefferson, then secretary of state, with a letter rebuking Jefferson for his proslavery views and urging the abolishment of slavery of the African American, which he compared to the enslavement of the American colonies by the British crown. Jefferson acknowledged Banneker's letter and forwarded the manuscript to the Marquis de Condorcet, the secretary of the Académie des Sciences in Paris. The exchange of letters between Banneker and Jefferson was published as a separate pamphlet and given wide publicity at the time the first almanac was published. The two letters were reprinted in Banneker's almanac for 1793, which also included "A Plan for an Office of Peace," which was the work of Dr. Benjamin Rush. The abolition societies of Maryland and Pennsylvania were largely instrumental in the publication of Banneker's almanacs, which were widely distributed as an example of the work of an African American that demonstrated the equal mental abilities of the races.

The last known issue of Banneker's almanacs appeared for the year 1797, because of diminishing interest in the antislavery movement; nevertheless, he prepared ephemerides for each year until 1804. He also published a treatise on bees and computed the cycle of the 17-year locust.

Banneker never married. He died on Oct. 9, 1806, and was buried in the family burial ground near his house. Among the memorabilia preserved was his commonplace book and the manuscript journal in which he had entered astronomical calculations and personal notations.

Banneker's memory was kept alive by writers who described his achievements as the first African American scientist. Recent studies have verified Banneker's status as an extremely competent mathematician and amateur astronomer.