One of the warmest of Smith's Swiss friends was Charles Bonnet, the celebrated naturalist and metaphysician, who, in writing Hume ten years after the date of this visit, desires to be remembered "to the sage of Glascow," adding, "You perceive I speak of Mr. Smith, whom we shall always recollect with great pleasure."[156] On the day this letter was written by Bonnet to Hume, another was written to Smith himself by a young Scotch tutor then in Geneva, Patrick Clason, who seems to have carried an introduction from Smith to Bonnet, and who mentions having received many civilities from Bonnet on account of his being one of Smith's friends. Clason then goes on to tell Smith that the Syndic Turretin and M. Le Sage also begged to be remembered to him. The Syndic Turretin was the President of the Republic, and M. Le Sage was the eminent Professor of Physics, George Louis Le Sage, who was then greatly interested in Professor Black's recent discoveries about latent heat and Professor Matthew Stewart's in astronomy, and was one of a group who gathered round Bonnet for discussions in speculative philosophy and morals, at which, it may be reasonably inferred, Smith would have also occasionally assisted. Le Sage seems to have met Smith first, however, and to have been in the habit of meeting him often afterwards, at the house of a high and distinguished French lady, the Duchesse d'Enville, who was living in Geneva under Tronchin's treatment, and whose son, the young and virtuous Duc de la Rochefoucauld, who was afterwards stoned to death in the Revolution, was receiving instruction from Le Sage himself. Le Sage writes the Duchesse d'Enville on 5th February 1766, "Of all the people I have met at your house, that is, of all the _elite_ of our good company, I have only continued to see the excellent Lord Stanhope and occasionally Mr. Smith. The latter wished me to make the acquaintance of Lady Conyers and the Duke of Buckleugh, but I begged him to reserve that kindness for me till his return."[157] This letter shows that Smith was so much taken with Geneva that he meant to pay it a second visit before he ended his tutorial engagement, but the intention was never fulfilled, in consequence of unfortunate circumstances to be presently mentioned.