During the winter of 1584-1585 Ralegh and Harriot made preparations for a colonizing effort. On 9 April 1585, commanded by Sir Richard Grenville, the expedition sailed from Plymouth. Unable to go himself, Ralegh named Harriot as his representative, charged with assessing the area's economic potential and describing the natives. John White was to make maps and to prepare drawings of the new land and its inhabitants. During the voyage Harriot made a number of observations. He tested dead reckoning against celestial navigation, noted the variation of the compass, and must have observed the eclipse of the sun on 19 April. Harriot also gathered plants as samples of the richness to be obtained by colonization. Once in America Harriot and White began their task of making a permanent record of the people and products of the new world. They noted commercially profitable plants and mineral resources. Harriot may have been in the group that explored the Chowan and Roanoke rivers and he may have spent part of the winter of 1585-1586 on the shores of the Chesapeake Bay. His scientific knowledge impressed the Indians who learned to trust him.
By the summer of 1586, when Sir Francis Drake arrived, the colonists were in dire straits. Supplies were low and the Indians unfriendly. He gave them a ship; however, a storm forced it out to sea. He then offered the colonists passage home. In their haste to depart much of the work of Harriot and White was lost.
Although Ralegh sent a second colony to Roanoke Island in 1587, he also had a colonial venture in Ireland where Harriot joined him and lived at the Abbey of Molanna near Youghal in County Waterford. There he prepared for publication the first English treatise on the new world. A briefe and true report of the new found land of Virginia, published in 1588. An important early account of America, it was included by Hakluyt in 1589 in his Principal navigations. The following year Theodor De Bry issued elaborate editions in Latin, English, French, and German adding plates of twenty-one of John White's drawings for which Harriot wrote captions. It established Harriot and White as leading authorities on America. Harriot helped to prepare the defenses for the invasion of the Spanish Armada. He developed a large collection of maps and ruttiers, worked with Emery Molyneaux in improving terrestrial globes, and assisted Gerard Mercator in developing accurate map projections. Harriot was one of the first modern scientists to use mathematics to analyze natural phenomena. His study of the piling of bullets let him to study the atomic structure of matter. His study of the trajectory of bullets led him to consider the laws of motion and falling bodies; thus, he performed the same experiments in England that Galileo conducted in Italy. This research led him to discover the law of refraction many years before the Dutchman Willebrord Snell. He worked on mirrors and lenses and may have made an independent discovery of a telescope.
During this period Ralegh's fortunes declined. His colonization attempts in the new world and in Ireland were disastrous. His favor with Queen Elizabeth, source of his wealth, had been jeopardized by his marriage to one of her ladies in waiting. Though he continued to be close to Ralegh, Harriot found a new patron, Ralegh's longtime friend, Henry Percy, ninth Earl of Northumberland.
In 1595 Northumberland granted Harriot a lifetime interest in his land holdings at Brampton in county Durham and established him in a house adjacent to his residence, Syon House, Isleworth. By 1597, Harriot was listed as a regular pensioner at 80 pounds per annum-the same amount the Earl's younger brothers received. With the support of Ralegh and Northumberland, Harriot could live like a gentleman and pursue new scientific knowledge without worrying about income.
The accession of James I in 1603 was bad for Ralegh, who was soon charged with treason, convicted, and thrown into the Tower. Two years later, because of a remote connection with the Gunpowder Plot, Northumberland followed him there. Harriot, questioned about that plot and accused by James of casting the royal horoscope, was imprisoned for a time, but later released. He became the main link between Ralegh and Northumberland in the Tower and the outside world, assisted Ralegh in his writing of the Historie of the World, and instructed the Earl's heir in the elements of mathematics and navigation.
Between 1606 and 1608 Harriot was in correspondence with Johannes Kepler, comparing notes on their experiments in the refraction of light and giving the scientific explanation to the dispersion of light in the rainbow. By 1609 he possessed a six-power telescope and began a series of observations of the moon. He developed at least eight new telescopes (called perspective truncks) ranging in power from eight to fifty. Harriot observed the phases of Venus, which proved the validity of the Copernican cosmology; made more that thirty drawings of the moon, which led to the first telescopic moon map; and determined the time of quadrature so that he could calculate the distance of the moon from the sun. In December 1610, almost simultaneously with Galileo, he discovered sunspots. In October 1610 he first saw the satellites surrounding Jupiter; two years later he calculated the distances of the moons from the planet and computed the periods of their revolution. He also observed the comets of 1607 (Halley's comet) and 1618 and determined that they followed elliptical orbits.
Suffering from cancer of the nose in his later years, Harriot died in 1621 at the home of Thomas Buckner, a mercer who lived on Threadneedle Street near the Royal Exchange. Buckner may have been the "Thomas Bookener" who was with Harriot on Roanoke Island in 1585-1586. Harriot was buried in the chancel of St. Christopher le Stocks, on the site of the present Bank of England. His grave and monument were destroyed in the Great Fire of 1666.
Text by John Shirley; edited by lebame houston and Wynne Dough