It is well known that Richard Hakluyt in a publication of 1581 congratulated Sir Walter Ralegh for employing Harriot to teach him and his many sea captains the sciences of navigation. Even more important, however, was the navigational research carried out by Harriot on behalf of Ralegh. He made important theoretical advances in map theory and in navigational astronomy, carried out the astronomical observations needed for a reform in navigational tables, and designed and himself tested at sea improved navigational instruments. Harriot had many other responsibilities in connexion with Ralegh's enterprises. From August 1585 to June 1586 Harriot was in Virginia, and in 1589 he was listed as one of Ralegh's colonists in Munster. He collected intelligence concerning America for Ralegh, and his publication of 1588 was effective as propaganda for Virginia. Harriot was also entrusted with financial, and even political responsibilities by Ralegh. Instructing Ralegh and his captains in navigation was an important part of Harriot's work but it is more likely that he did this as the occasion demanded, rather than on a regular basis.

The Philosophical Society of Edinburgh which had flourished for a few years after 1738 was as good as dead in 1748. Lord Morton, its President, now lived most of the time in London whence he wrote to Sir John Clerk in 1747 that he regarded the Society as ‘annihilated’, apparently thinking that the death of Colin MacLaurin in 1746 and the temporary retirement to the countryside of its other Secretary, Andrew Plummer, had put an end to it. Sir John had hoped to revive it through association with the Royal Society of London, but Morton did not encourage him in this scheme, about which he had ‘great doubts’. The Society needed a mathematician and an experimenter who could carry on the consulting work which MacLaurin had done, but Morton glumly wondered if ‘the new professor of Mathematics [Matthew Stewart] will be as zealous as MacLaurin had been.’ The Society's other officers, Dr John Clerk and Alexander Lind, are not known to have tried to revive the Society. Perhaps they were discouraged by the fact that ten (22%) of the members of the Society were dead, and that six more (1396) had left the kingdom. At least three others (7%) were likely to have been habitually absent from meetings because they lived some distance from Edinburgh. Of the remaining forty-five known members in 1748, nine (20%) were over sixty-one years of age with four being between seventy-one and seventy-six. In 1737 the average age of thirty-eight of the founders had been 46.0, but by 1748 it had risen to 53.9 for the thirty-three men for whom it can be calculated. Disruption, death, and age had diminished enthusiasm for the Society and jeopardized its survival. Only two meetings are known to have been held in 1746. Sir John's letter to Morton about affiliation with the Royal Society is the only clear sign of life in 1747. We may well ask why this floundering body survived, to whom and to what it owed its revival? The answers to these questions tell us something about the intellectual needs and interests of the Edinburgh intelligentsia of the mid-eighteenth century.