A free Black tobacco farmer taught himself the heavens after fifty — then put them in print.
In 1788, on a hundred-acre farm in the Patapsco valley of Maryland, a man of fifty-six borrowed a telescope, drafting instruments and a small stack of astronomy books from a Quaker neighbour. Nobody taught him how to use them. Within a year he had calculated a coming eclipse; within three he had computed a full ephemeris — the positions of sun, moon and planets for every day of a year — and sent it, with a letter, to the Secretary of State of the United States.
That letter asked Thomas Jefferson, author of the words all men are created equal, to square them with slavery. Benjamin Banneker was born free, the grandson of an enslaved African, in a Maryland that by 1790 held more than 100,000 people in slavery. His almanacs sold in seven cities as living proof against the argument Jefferson himself had made in print: that Black Americans lacked the capacity for science.
A life by the Patapsco
The lifeline
1731
Born free on 9 November in Baltimore County, Maryland, to Robert and Mary Banneky
c.1753
Carves a working wooden clock, modelled on a borrowed pocket watch
1788
Borrows astronomy books and instruments from George Ellicott; teaches himself
1791
Helps survey the new federal capital; writes to Jefferson on 19 August
1792
His first almanac goes on sale — the start of a six-year run
1806
Dies at 74; on the day of his funeral his cabin burns, clock and papers with it
By the numbers
The measure of him
28
Editions of his almanacs, printed in 7 cities across 5 states, 1792–1797
50+ yrs
How long his hand-carved wooden clock kept time — until his death
40
Boundary stones set around the 10-mile square his survey party laid out
17
Years between cicada swarms — he logged them in 1749, 1766 and 1783
What he made and measured
The work
c.1753
The wooden clock. Having studied a borrowed watch, he scaled up each gear and carved it by hand. It is said to have struck the hours for the rest of his life.
1789
An eclipse, predicted. A year after opening his first astronomy book, he sent George Ellicott his own calculation of a coming solar eclipse.
1791
The capital's first survey. From February to April he kept the observatory tent for Major Andrew Ellicott, fixing positions by the stars as the boundary of the federal district was run.
1791
The letter to Jefferson. Sent with his manuscript ephemeris, calling the author of the Declaration to account for slavery. Jefferson replied on 30 August and forwarded the almanac to the Marquis de Condorcet in Paris.
1792–97
The almanacs. Tide tables, eclipses, planetary positions and weather, alongside essays and anti-slavery writing. The 1793 edition printed both letters.
1800
The cicada journal. In his one surviving notebook he described the 17-year cicada, among the earliest records of its cycle.
Doubted, then honoured
Recognition
In his lifetime
Praised by Jefferson in 1791, yet privately dismissed by him in 1809 as likely helped by Ellicott
His almanacs stopped after 1797 for want of a publisher
Nearly all his papers, and the clock, burned on the day of his funeral
Later remembered through a legend that he redrew L'Enfant's city plan from memory — untrue, as he had left the survey ten months before L'Enfant was dismissed
Today
A 15¢ U.S. stamp in the Black Heritage series, issued 15 February 1980
A 138-acre historical park and museum on the site of his farm, dedicated 1998
A statue in the Smithsonian's National Museum of African American History and Culture
A boundary stone, parks, schools and streets bear his name
The place that made him
The Patapsco Valley
He lived his whole life on one farm above the Patapsco River, west of Baltimore, growing tobacco and keeping bees. When the Ellicott brothers built their mills just upriver, their Quaker family became his neighbours, lenders of books and, in time, his road to print. The land is now Oella, and the farm a park.
100 acres
The family farm, deeded to his father and him in 1737
1772
The year the Ellicotts began their mills on the river nearby
138 acres
Today's Benjamin Banneker Historical Park, on the farm site
"However variable we may be in Society or religion, however diversified in Situation or colour, we are all of the Same Family, and Stand in the Same relation to him."
— Benjamin Banneker, to Thomas Jefferson, 19 August 1791
