The lectures Smith then delivered on English literature were burnt at his own request shortly before his death.  Blair, who not only heard them at the time, but got the use of them—­or, at least, of part of them—­afterwards for the preparation of his own lectures on rhetoric, speaks as if there was some hope at one time that Smith would publish them, but if he ever entertained such an intention, he was too entirely preoccupied with work of greater importance and interest to himself to obtain leisure to put them into shape for publication.  It has been suggested that they are practically reproduced in the lectures of Blair.  Blair acknowledges having taken a few hints for his treatment of simplicity in style from the manuscript of Smith’s lectures.  His words are:  “On this head, of the general characters of style, particularly the plain and the simple, and the characters of those English authors who are classed under them, in this and the following lecture, several ideas have been taken from a manuscript treatise on rhetoric, part of which was shown to me many years ago by the learned and ingenious author, Dr. Adam Smith; and which it is hoped will be given by him to the public."[21] Now many of Smith’s friends considered this acknowledgment far from adequate, and Hill, the biographer of Blair, says Smith himself joined in their complaint.  It is very unlikely that Smith ever joined in any such complaint, for Henry Mackenzie told Samuel Rogers an anecdote which conveys an entirely contrary impression.  Mackenzie was speaking of Smith’s wealth of conversation, and telling how he often used to say to him, “Sir, you have said enough to make a book,” and he then mentioned that Blair frequently introduced into his sermons some of Smith’s thoughts on jurisprudence, which he had gathered from his conversation, and that he himself had told the circumstance to Smith.  “He is very welcome,” was the economist’s answer; “there is enough left."[22] And if Smith made Blair welcome to his thoughts on jurisprudence, a subject on which he intended to publish a work of his own, we may be certain he made him not less heartily welcome to his thoughts on literature and style, on which he probably entertained no similar intention.  Besides, if we judge from the two chapters regarding which he owns his obligation to Smith, Blair does not seem to have borrowed anything but what was the commonest of property already.  He took only what his superficial mind had the power of taking, and the pith of Smith’s thinking must have been left behind.  To borrow even a hat to any purpose, the two heads must be something of a size.