Banneker's interest in mathematics began at an early age when he used his knowledge to build a clock that struck hourly. Later in life he took a strong interest in anstronomy, and was able to perform detailed calculations that predicted solar and lunar eclipses. He kept his information in a series of journals that also included additional advanced mathematical calculations.
Benjamin Banneker (1731-1806), an African American mathematician and amateur astronomer, calculated ephemeredes 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 ephemeredes (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…