After being established in Kirkcaldy for some weeks Smith wrote Hume that he was immersed in study, which was the only business he had, that his sole amusements were long solitary walks by the seaside (which, with a man of his gift or infirmity of abstraction, would only be protractions of the study that preoccupied him), and that he never was happier or more contented in all his life.  The immediate object of this letter, as so usual with Smith, was to serve a friend—­a motive which never failed to overcome his aversion to writing.  A French friend—­“the best and most agreeable friend I had in France,” says Smith—­was then in London, and Smith wishes Hume, who was now Under Secretary of State, to show him some attentions during his residence there.  This friend was Count de Sarsfield, a gentleman of Irish extraction, an associate of Turgot and the other men of letters in Paris, and a man who added to almost universal knowledge a special predilection for economics, and indeed wrote a number of essays on economic questions, though he never published any of them.  He seems to have really been, as Smith indicates, the perfection of an agreeable companion.  John Adams, the second President of the United States, when envoy for that country in Paris, was very intimate with him, and says that Sarsfield was the happiest man he knew, for he led the life of a peripatetic philosopher.  “Observation and reflection are all his business, and his dinner and his friend all his pleasure.  If a man were born for himself alone, I would take him for a model."[201] He was “the greatest rider of hobby-horses” in all President Adams’s acquaintance, and some of his hobbies were for the most serious studies.  He published a work in metaphysics, and wrote essays against serfdom and slavery, and on a number of other subjects, which were found in MS. among President Adams’s papers.  Yet he was a problem—­and not a very soluble one—­to the worthy President, for he laid a weight on the merest trifles of ceremony or etiquette which seemed difficult to reconcile with his devotion to profound and learned studies.  He visited Adams at Washington during his presidency, and used constantly to lecture the President on his little omissions.  After any entertainment Sarsfield would say, writes Adams, “that I should have placed the Ambassador of France at my right hand and the Minister of Spain at my left, and have arranged the other principal personages; and when I rose from the table I should have said, Messieurs, voudrez vous, etc., or Monsieur or Duc voudrez vous, etc....  How is it possible to reconcile these trifling contemplations of a master of the ceremonies with the vast knowledge of arts, sciences, history, government, etc., possessed by this nobleman?"[202] Sarsfield kept a journal about all the people he met with, from which Adams makes some interesting quotations, and which, if extant, might be expected to add to our information regarding Smith.  Having said so much of Smith’s “best and most agreeable friend in France,” I will now give the letter:—­