From 1731 to 1806.
It is the indispensable duty of those who maintain for themselves the rights of human nature, and who possess the obligations of Christianity, to extend their power and influence to the relief of every part of the human race from whatever burden or oppression they may unjustly labor under.
Benjamin Banneker is best known for his work in surveying the District of Columbia, but it is just one of many achievements. Banneker's father, Robert, was a slave who was granted his freedom and converted to Christianity. His mother, Mary, along with the help of Robert, owned and managed a successful tobacco farm west of Baltimore, Maryland. Born a free black, Banneker had very little formal education because of the tasks required of him for farm life. His grandmother, Molly Welsh, taught him to read and write.
In a prelude to his scientific achievements, at the age of 22, Banneker borrowed a pocket watch and built a wooden clock from scratch, a major technical feat in the colonial era. The clock kept precise time his entire life and chimed every hour for more than 50 years.
Banneker revealed himself to be a capable laborer, manager, and owner of his tobacco farm. His biographer, Silvio Bedini, described him as a loner but because of the fame that followed the invention of his clock, neighbors in the community sought out Banneker's counsel. Bedini declared he was admired for his "dignity, reticence, and gentlemanly qualities." The first book he purchased was a copy of the Bible. Banneker's 1806 obituary in the Baltimore Daily Advertiser declared there was "no book he was more attached to than the Scriptures."
He was befriended by The Society of Friends and a wealthy family in the area named the Ellicotts. George Ellicott lent him a telescope and other equipment for astronomical studies, thus cultivating his lifelong fascination with the heavens. He later worked with George's cousin, Major Andrew Ellicott, on the team that surveyed Washington D.C. in 1791.
With the help of abolitionists, he published his first almanac in 1792 which included astronomical calculations for the setting and rising of the moon and sun, tide tables, and weather forecasts. Banneker's work not only received commercial success but his mathematic calculations were endorsed by some of the most prominent American astronomers. He published almanacs up to 1797 and they often included essays on abolition, poems, and works related to Christian devotion and virtue. In his 1793 edition, Banneker included correspondence between himself and Thomas Jefferson on issues of human liberty and slavery. Banneker's work allowed for him to retain a level of financial independence and he was able to devote his time more fully to astronomy.
He is admired by many black Americans for his achievements, but his life also serves as an example that it is never too late to learn. He started his formal self-education in mathematics and astronomy in his late 50s. Banneker was lauded by notable English parliamentarian William Wilberforce on the floor of the House of Commons for his scientific contributions. Despite the many obstacles Banneker faced in life, his witness points to the possibilities of human flourishing in a society that promotes freedom and virtue.