Those three years were spent upon the Wealth of Nations.  Much of the book as we know it must have been written in London.  When he went up to London he had no idea that any fresh investigations he contemplated instituting there would detain him so long.  He wrote Pulteney, as we have seen, even in the previous September that the book would be finished in a few months, and he led not only Hume but Adam Ferguson also to look for its publication in 1773.  In a footnote to the fourth edition of his History of Civil Society, published in that year, Ferguson says, “The public will probably soon be furnished (by Mr. Smith, author of the Theory of Moral Sentiments) with a theory of national economy equal to what has ever appeared on any subject of science whatever.”  But the researches the author now made in London must have been much more important than he expected, and have occasioned extensive alterations and additions, so that Hume, in congratulating him on the eventual appearance of the work in 1776, writes, “It is probably much improved by your last abode in London.”  Whole chapters seem to have been put through the forge afresh; and on some of them the author has tool-marked the date of his handiwork himself.

A very circumstantial account of Smith’s London labours at the book comes from America.  Mr. Watson, author of the Annals of Philadelphia, says:  “Dr. Franklin once told Dr. Logan that the celebrated Adam Smith when writing his Wealth of Nations was in the habit of bringing chapter after chapter as he composed it to himself, Dr. Price, and others of the literati; then patiently hear their observations and profit by their discussions and criticisms, sometimes submitting to write whole chapters anew, and even to reverse some of his propositions."[232]

Franklin’s remark may have itself undergone enlargement before it appeared in print, but though it may have been exaggerated, there seems no ground for rejecting it altogether.  Smith became acquainted with Franklin in Edinburgh in 1759, and could not fail to see much of him in London, because some of the most intimate of his own London friends, Sir John Pringle and Strahan, for example, were also among the most intimate friends of Franklin.  Then a considerable proportion of the additions, which we know from the text of the Wealth of Nations itself to have been made to the work during this London period, bear on colonial or American experience.[233] And as Smith always obtained a great deal of his information from the conversation of competent men, no one would be more likely than Franklin to be laid under contribution or to be able to contribute something worth learning on such questions.  The biographer of Franklin states that his papers which belong to this particular period “contain sets of problems and queries as though jotted down at some meeting of philosophers for particular consideration at home,” and then he adds:  “A glance at the index of the