Thomas Harriot

A contemporary of Shakespeare, Elizabeth I, Johannes Kepler, and Galilei Galileo, Thomas Harriot (1560-1621) was an English scientist and mathematician. His principal biographer, J. W. Shirley, was quoted in the website "Thomas Harriot's manuscripts," saying that in his time he was "England's most profound mathematician, most imaginative and methodical experimental scientist, and first of all Englishmen to make a telescope and turn it on the heavens." He was also an early English explorer of North America. He published very little in his life time, and the extensive scientific papers he left at his death suffered loss and then neglect until the twentieth century.

Educated at Oxford

Harriot was born in Oxfordshire, England, in 1560. Nothing is known about his parents except that his father was recorded as a plebeian when Harriot entered the University of Oxford on December 20, 1577. Of Harriot's early school years a boyhood friend, Tom Buckner, one day wrote, as quoted in Thomas Harriot: Science Pioneer, "Tom Harriot had a far greater gift for language than I had. He enjoyed reading the writings of the ancient Romans, sharpening his language abilities through disputation and debate, and writing poetry in Latin." Harriot was a good student. At Oxford he attended St. Mary's Hall with other students from the plebeian class. He became friends with two of his teachers, Richard Hakluyt, a geographer, and Thomas Allen, who had an interest in astronomy and was a suspicious figure to some because of the unusual instruments in his rooms. Harriot continued to do well in his studies and was one of only three in his class to receive a bachelor's degree in July 1580.

Sponsored by Raleigh

While Harriot was enrolled in St. Mary's Hall, Walter Raleigh had attended Oxford's Oriel College, the preserve of the gentry and nobility. Raleigh was already involved in exploration in North America when Harriot graduated. Raleigh and his half brother Sir Humphrey Gilbert had sailed with 11 ships to the Cape Verde Islands in 1578, and the ships had become badly scattered en route. Raleigh wanted someone to teach reliable navigation techniques to his ship captains. The principal at St. Mary's recommended Harriot, and Raleigh became Harriot's first patron. Harriot moved to Raleigh's London residence, Durham House.

Harriot made several investigations to prepare a course for English navigators. He interviewed ships' captains at the docks along the Thames River. His friends Allen and Hakluyt from Oxford helped him. He also read John Dee's translation of Martin Cortes' Arte de navigation. The result was a textbook he named Arcticon. Only the names of its chapters have survived; some of them were "Some Remembrances of taking the altitude of the Sonne by Astrolabe and Sea Ring," "How to find the declination of the Sonne for any time of the yeare & any place; by a speciall table called the Sonnes Regiment newly made according to late observations," and "Effect of longitude on declination."

Traveled to Virginia

When Raleigh received permission to sail to North America in 1584, Harriot may have accompanied him, but there are no records to confirm it. He is known to have sailed for the Western Hemisphere with Sir Richard Grenville in 1585. En route Harriot made many observations of the sun and stars to track his course, and he also observed a partial solar eclipse. The ship sighted Dominica in the Caribbean, then moved northward. On June 30, 1585, it anchored at Roanoke Island, off Virginia. On shore, Harriot observed the topography, flora, and fauna, making many drawings and maps, and the native people, who spoke a language the English called Algonquian. Harriot worked out a phonetic transcription of the native people's speech sounds and began to learn the language, which enabled him to converse to some extent with other natives the English encountered. Apparently Harriot favored friendly relations with the native people, but others in the party felt otherwise, and at least one of the native people was killed. At the same time, Sir Francis Drake, patrolling the Florida coast for Spanish treasure galleons to capture, heard the Spanish planned to attack the colony at Roanoke. He sailed north to warn the English and took most of them back to England in 1586. Harriot wrote his report for Raleigh and published it as A Briefe and True Report of the New Found Land of Virginia in 1588. Raleigh gave Harriot his own estate, in Ireland, and Harriot began a survey of Raleigh's Irish holdings. He also undertook a study of ballistics and ship design for Raleigh in advance of the Spanish Armada's arrival.

Security Shaken

Two events made Raleigh's and Harriot's lives stressful about this time. First, Raleigh's political situation became murky when he married Elizabeth Throckmorton, one of Queen Elizabeth's ladies in waiting, in 1587. He had been a favorite of Elizabeth, and the marriage may have displeased the queen. Second, the queen issued a proclamation on October 18, 1591, attacking Jesuits in England for trying to return the country to Catholicism. Perhaps in retaliation, Jesuit father Robert Parsons attacked Elizabeth's sometime friend Raleigh, as well as Harriot, accusing them of atheism.

Then in 1592, soon after Raleigh's son was born, Elizabeth imprisoned Raleigh and his family in the Tower of London. Coincidentally, one of Raleigh's ships captured a Spanish treasure ship, the Madre de Deus, not long after the imprisonment. With Raleigh in prison, the ship was being gradually looted. Elizabeth wanted the greater part of its fortune for England's treasury, so Raleigh and his family were released so that Raleigh could stop the looting. Harriot remained under Raleigh's patronage in Ireland, avoiding the plague that struck London in 1593.

Harriot Studied Optics, Algebra

In 1595, the Duke of Northumberland, Henry Percy, a great friend of Raleigh's, became Harriot's patron and deeded him property in Durham as well as allowing him use of a house in London. Harriot undertook a study of optics, using part of the house as a laboratory. The studies eventually led to several important discoveries concerning the refraction of light, but Harriot never published his results. He also began to analyze the forces affecting projectiles and commenced various studies in algebra. He and earlier mathematicians may have made several discoveries often credited to Rene Descartes (1596-1650). He wrote Artis Analyticae Praxis ad Aequationes Algebraicas Resolvendas, an algebra text, and left specific instructions for its publication in his will, but knowledgeable mathematicians reportedly think that the work which was eventually published represents Harriot's efforts poorly. His body of work in algebra is considerable. He advanced the notation system for algebra (although the "greater than" and "less than" symbols that have been credited to him are now thought to have been introduced by the editor of Artis Analyticae Praxis ) and did novel work on the theory of equations, including cubic equations and negative and imaginary numbers.

Queen Elizabeth died in March 1603, and James I became king. Raleigh was implicated in a plot against the new king and was arrested and charged with high treason. After a failed suicide attempt, Raleigh was sentenced to death, and Harriot, who had tried to help his former friend and patron, was mentioned in the judgment as "an atheist and an evil influence." Harriot, apparently shaken, ceased scientific work for about a year. Raleigh's death sentence was withdrawn, but he remained in the Tower of London. Then Guy Fawkes was arrested on November 4, 1604, for a plot to blow up Parliament. Henry Percy's grandson was arrested with Fawkes, and Harriot was imprisoned in a place called the Gatehouse on suspicion. Later in November, Percy was imprisoned in the Tower to remain for 16 years.

Moons, Sunspots Observed

Harriot was released by the end of 1604 and quickly resumed his study of optics, still under Percy's generous patronage. He also visited Percy and Raleigh in the Tower from time to time. Harriot was working out a theory of color, and a correspondence began between him and the German astronomer Johannes Kepler, although nothing memorable seems to have resulted. Harriot went on to observe a comet, later identified as Halley's, on September 17, 1607. With his painstaking observations, later workers were able to compute the comet's orbit. Harriot also was the first in England to use a telescope to observe the heavens. He made sketches of the moon in 1609, then developed lenses of increasing magnification. By April 1611, he had developed a lens with a magnification of 32. Between October 17, 1610, and February 26, 1612, he observed the moons of Jupiter, already discovered by Galileo. While observing Jupiter's moons, he made a discovery of his own: sunspots, which he viewed 199 times between December 8, 1610, and January 18, 1613. These observations allowed him to figure out the sun's period of rotation. After this time, his scientific work dwindled.

Cancer Diagnosed

The cause of Harriot's diminished productivity may have been a cancer discovered on his nose. A doctor he consulted in 1615 made notes in which he called Harriot "a man somewhat melancloly… . A cancerous ulcer in the left nostril eats up the septum of his nose and in proportion to its size holds the lips hard and turned upwards… . This evil the patient has suffered the last two years," quoted the "Thomas Harriot" website. Harriot lost several friends during this time, and on October 29, 1618, he witnessed the public execution of his friend Raleigh.

Three days before Harriot died, he made his will. His mind was clear. He willed Percy charts and maps and his choice of books and papers. He remembered friends, servants, and Tom Buckner, a childhood friend with whom he maintained contact all his life and who had accompanied him on Grenville's trip to America. In the will, Harriot mentioned a sister, whose son he left fifty pounds, and a cousin. Most evidence suggests they were his only family when he died; it seems he never married. He remembered his servants generously, as well as Tom Buckner's wife (in whose house he died) and the Buckners' son.

Harriot died July 1 or 2 (accounts vary), 1621, in London and was buried in Saint Christopher's Parish Church, which burned in the fire of London in 1666. According to Thomas Harriot: Science Pioneer, after the fire an inscription was incorporated in a plaque in the Bank of England of London which reads, Harriot "cultivated all the sciences And excelled in all." The plaque calls him "A most studious searcher after truth." Harriot was several times accused of atheism during his lifetime, but the plaque adds that he was "a most devout worshiper of the Triune God."

Papers Rediscovered

Harriot's story did not end with his death. What some writers describe as his "thousands upon thousands of sheets of mathematics and of scientific observations" appeared to be lost-until 1784, when they were found in Henry Percy's country estate by one of Percy's descendants. She gave them to Franz Xaver Zach, her husband's son's tutor. Zach eventually put some of the papers in the hands of the Oxford University Press, but much work was required to prepare them for publication, and it has never been done. Scholars have begun to study them, and an appreciation of Harriot's contribution began to grow in the second half of the twentieth century. Today scholars, sometimes referred to as "Harrioteers," study the details of his life and work to understand both the man and the science of his time.


Staiger, Ralph C., Thomas Harriot: Science Pioneer, Clarion Books, 1998.


Apt, Adam Jared, "Harriot, Thomas," Encyclopaedia Britannica Library,, 2003.

O'Connor, J. J., and E. F. Robertson, "Thomas Harriot," (March 1, 2003).

—, "Thomas Harriot's Manuscripts," (March 16, 2003).

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