Wealth of Nations will suffice to show that its author possessed just that kind of knowledge of the American Colonies which Franklin was of all men the best fitted to impart.  The allusions to the Colonies may be counted by hundreds; illustrations from their condition and growth occur in nearly every chapter.  We may go further and say that the American Colonies constitute the experimental evidence of the essential truth of the book, without which many of its leading positions had been little more than theory."[234] It ought of course to be borne in mind that Smith had been in the constant habit of hearing much about the American Colonies and their affairs during his thirteen years in Glasgow from the intelligent merchants and returned planters of that city.

After coming to London Smith seems to have renewed his acquaintance with Lord Stanhope, who sought Smith’s counsel as to a tutor for his ward the Earl of Chesterfield, and appointed Adam Ferguson on Smith’s recommendation.  The negotiations with Ferguson were conducted through Smith, and some of Ferguson’s letters to Smith on the matter still exist, but contain nothing of any interest for the biography of the latter.  But in contemplation of Ferguson’s going abroad with the Earl of Chesterfield, Hume, ever anxious to have his friend near him, sounds Smith on the possibility of his agreeing to act during Ferguson’s absence as his substitute in the Moral Philosophy chair at Edinburgh.  Smith, however, was apparently unwilling to undertake that duty.  As we have already seen, he was strongly opposed to professorial absenteeism, and in the present case it was associated with unpleasant circumstances.  The Town Council, the administrators of the College, refused to sanction Ferguson’s absence, and called upon him either to stay at home or to resign his chair.  Ferguson merely snapped his fingers, appointed young Dugald Stewart his substitute, and went off on his travels, quietly remarking that fools and knaves were necessary in the world to give other people something to do.  Hume’s letter is as follows:—­

     ST. ANDREW’S SQUARE, 13th February 1774.

DEAR SMITH—­You are in the wrong for never informing me of your intentions and resolutions, if you have fix’d any.  I am now obliged to write to you on a subject without knowing whether the proposal, or rather Hint, which I am to give you be an absurdity or not.  The settlement to be made on Ferguson is a very narrow compensation for his class if he must lose it.  He wishes to keep it and to serve by a Deputy in his absence.  But besides that this scheme will appear invidious and is really scarce admissible, those in the Town Council who aim at filling the vacancy with a friend will strenuously object to it, and he himself cannot think of one who will make a proper substitute.  I fancy that the chief difficulty would be removed if you could offer to supply his class either as his substitute or his successor, with a purpose