Thomas Harriot ('hæriət; 1560 – 2 July 1621), also spelled Harriott, Hariot or Heriot, was an English astronomer, mathematician, ethnographer and translator to whom the theory of refraction is attributed. Thomas Harriot was also recognized for his contributions in navigational techniques, working closely with John White to create advanced maps for navigation. While Harriot worked extensively on numerous papers on the subjects of astronomy, mathematics and navigation, he remains obscure because he published little of it, namely only The Briefe and True Report of the New Found Land of Virginia (1588). This book includes descriptions of English settlements and financial issues in Virginia at the time. He is sometimes credited with the introduction of the potato to the British Isles. Harriot invented binary notation and arithmetic several decades before Gottfried Wilhelm Leibniz, but this remained unknown until the 1920's. He was also the first person to make a drawing of the Moon through a telescope, on 5 August 1609, about four months before Galileo Galilei. After graduating from St Mary Hall, Oxford, Harriot traveled to the Americas, accompanying the 1585 expedition to Roanoke island funded by Sir Walter Raleigh and led by Sir Ralph Lane. He learned the Carolina Algonquian language from two Native Americans, Wanchese and Manteo, and could translate it, making him a vital member of the expedition. On his return to England, he worked for the 9th Earl of Northumberland. Born in 1560 in Oxford, England, Thomas Harriot attended St Mary Hall, Oxford. His name appears in the hall's registry dating from 1577. Harriot started to study navigation shortly after receiving a bachelor's degree from Oxford University. The study of navigation that Harriot studied concentrated on the idea of the open seas and how to cross to the New World from the Atlantic Ocean. He used instruments such as the astrolabe and sextants to aide his studies of navigation. After educating himself by incorporating ideals from his astronomic and nautical studies, Harriot taught other captains his navigational techniques in Raleigh.