His characteristics as a lecturer are thus described by Millar:—
"There was no situation in which the abilities of Mr. Smith appeared to greater advantage than as a professor. In delivering his lectures he trusted almost entirely to extemporary elocution. His manner, though not graceful, was plain and unaffected, and as he seemed to be always interested in the subject, he never failed to interest his hearers. Each discourse consisted commonly of several distinct propositions, which he successively endeavoured to prove and illustrate. These propositions when announced in general terms had, from their extent, not unfrequently something of the air of a paradox. In his attempts to explain them, he often appeared at first not to be sufficiently possessed of the subject, and spoke with some hesitation. As he advanced, however, his manner became warm and animated, and his expression easy and fluent. On points susceptible of controversy you could easily discern that he secretly conceived an opposition to his opinions, and that he was led upon this account to support them with greater energy and vehemence. By the fulness and variety of his illustrations the subject gradually swelled in his hands and acquired a dimension which, without a tedious repetition of the same views, was calculated to seize the attention of his audience, and to afford them pleasure as well as instruction in following the same subject through all the diversity of shades and aspects in which it was presented, and afterwards in tracing it backwards to that original proposition or general truth from which this beautiful train of speculation had proceeded."[44]
One little peculiarity in his manner of lecturing was mentioned to the late Archdeacon Sinclair by Archibald Alison the elder, apparently as Alison heard it from Smith's own lips. He used to acknowledge that in lecturing he was more dependent than most professors on the sympathy of his hearers, and he would sometimes select one of his students, who had more mobile and expressive features than the rest, as an unsuspecting gauge of the extent to which he carried with him the intelligence and interest of the class. "During one whole session," he said, "a certain student with a plain but expressive countenance was of great use to me in judging of my success. He sat conspicuously in front of a pillar: I had him constantly under my eye. If he leant forward to listen all was right, and I knew that I had the ear of my class; but if he leant back in an attitude of listlessness I felt at once that all was wrong, and that I must change either the subject or the style of my address."[45]
The great majority of his students were young men preparing for the Presbyterian ministry, a large contingent of them—quite a third of the whole—being Irish dissenters who were unfairly excluded from the university of their own country, but appear to have been no very worthy accession to the University of Glasgow. We know of no word of complaint against them from Smith, but they were a sore trial both to Hutcheson and to Reid. Reid says he always felt in lecturing to those "stupid Irish teagues" as St. Anthony must have felt when he preached to the fishes,[46] and Hutcheson writes a friend in the north of Ireland that his Irish students were far above taking any interest in their work, and that although he had "five or six young gentlemen from Edinburgh, men of fortune and fine genius, studying law, these Irishmen thought them poor bookworms."[47] Smith had probably even more of this stamp of law students than Hutcheson. Henry Erskine attended his class on jurisprudence as well as his elder brother. Boswell was there in 1759, and was made very proud by the certificate he received from his professor at the close of the session, stating that he, Mr. James Boswell, was "happily possessed of a facility of manners."[48] After the publication of the Theory of Moral Sentiments, students came even from a greater distance. Lord Shelburne, who was an enthusiastic admirer of that work, sent his younger brother, the Honourable Thomas Fitzmaurice, for a year or two to study under Smith, before sending him to Oxford in 1761 to read law with Sir William Blackstone. Mr. Fitzmaurice, who married the Countess of Orkney, and is the progenitor of the present Orkney family, rose to a considerable political position, and would have risen higher but for falling into ill health in the prime of life and remaining a complete invalid till his death in 1793, but he never forgot the years he spent as a student in Smith's class and a boarder in Smith's house. Dr. Currie, the well-known author of the Life of Burns, was his medical attendant in his latter years, and Dr. Currie says his conversation always turned back to his early life, and particularly to the pleasant period he had spent under Smith's roof in Glasgow. Currie has not, however, recorded any reminiscences of those conversations.[49] Two Russian students came in 1762, and Smith had twice to give them an advance of £20 apiece from the College funds, because their remittances had got stopped by the war. Tronchin, the eminent physician of Geneva, the friend of Voltaire, the enemy of Rousseau, sent his son to Glasgow in 1761 purposely "to study under Mr. Smith," as we learn from a letter of introduction to Baron Mure which the young man received before starting from Colonel Edmonston of Newton, who was at the time resident in Geneva. It was of Tronchin Voltaire said, "He is a great physician, he knows the mind," and he must have formed a high idea of the Theory of Moral Sentiments to send his son so far to attend the lectures of its author. It was this young man who, on his way back from Glasgow, played a certain undesigned part in originating the famous quarrel between Rousseau and Hume, of which we shall have more to hear anon. He was living with Professor Rouet of Glasgow, at Miss Elliot's lodging-house in London, when Hume brought Rousseau there in January 1866, and the moment Rousseau saw the son of his old enemy established in the house to which he was conducted, he flew to the conclusion that young Tronchin was there as a spy, and that the good and benevolent Hume was weaving some infernal web about him.
Smith's popularity as a lecturer grew year by year. It was felt that another and perhaps greater Hutcheson had risen in the College. Reid, when he came to Glasgow to succeed him in 1764, wrote his friend Dr. Skene in Aberdeen that there was a great spirit of inquiry abroad among the young people in Glasgow—the best testimony that could be rendered of the effect of Smith's teaching. It had taught the young people to think. His opinions became the subjects of general discussion, the branches he lectured on became fashionable in the town, the sons of the wealthier citizens used to go to College to take his class though they had no intention of completing a university course, stucco busts of him appeared in the booksellers' windows, and the very peculiarities of his voice and pronunciation received the homage of imitation. One point alone caused a little—in certain quarters not a little—shaking of heads, we are told by John Ramsay of Ochtertyre. The distinguished professor was a friend of "Hume the atheist"; he was himself ominously reticent on religious subjects; he did not conduct a Sunday class on Christian evidences like Hutcheson; he would often too be seen openly smiling during divine service in his place in the College chapel (as in his absent way he might no doubt be prone to do); and it is even stated by Ramsay that he petitioned the Senatus on his first appointment in Glasgow to be relieved of the duty of opening his class with prayer, and the petition was rejected; that his opening prayers were always thought to "savour strongly of natural religion"; that his lectures on natural theology were too flattering to human pride, and induced "presumptuous striplings to draw an unwarranted conclusion, viz. that the great truths of theology, together with the duties which man owes to God and his neighbours, may be discovered by the light of nature without any special revelation,"[50] as if it were a fault to show religious truth to be natural, for fear young men should believe it too easily. No record of the alleged petition about the opening prayers and its refusal remains in the College minutes, and the story is probably nothing but a morsel of idle gossip unworthy of attention, except as an indication of the atmosphere of jealous and censorious theological vigilance in which Smith and his brother professors were then obliged to do their work.
In his lectures on jurisprudence and politics he had taught the doctrine of free trade from the first, and not the least remarkable result of his thirteen years' work in Glasgow was that before he left he had practically converted that city to his views. Dugald Stewart was explicitly informed by Mr. James Ritchie, one of the most eminent Clyde merchants of that time, that Smith had, during his professorship in Glasgow, made many of the leading men of the place convinced proselytes of free trade principles.[51] Sir James Steuart of Coltness, the well-known economist, used, after his return from his long political exile in 1763, to take a great practical interest in trying to enlighten his Glasgow neighbours on the economical problems that were rising about them, and having embraced the dying cause in economics as well as in politics, he sought hard to enlist them in favour of protection, but he frankly confesses that he grew sick of repeating arguments for protection to these "Glasgow theorists," as he calls them, because he found that Smith had already succeeded in persuading them completely in favour of a free importation of corn.[52] Sir James Steuart was a most persuasive talker; Smith himself said he understood Sir James's system better from his talk than from his books,[3] and those Glasgow merchants must have obtained from Smith's expositions a very clear and complete hold indeed of the doctrines of commercial freedom, when Steuart failed to shake it, and was fain to leave such theorists to their theories. Long before the publication of the Wealth of Nations, therefore, the new light was shining clearly from Smith's chair in Glasgow College, and winning its first converts in the practical world. One can accordingly well understand the emotion with which J.B. Say sat in this chair when he visited Glasgow in 1815, and after a short prayer said with great fervour, "Lord, let now thy servant depart in peace."[53]
Dugald Stewart further states, on the authority of gentlemen who were students in the moral philosophy class at Glasgow in 1752 or 1753, that Smith delivered so early as that lectures containing the fundamental principles of the Wealth of Nations; and in 1755—the year Cantillon's Essai first saw the light, and the year before Quesnay published his first economic writing—Smith was not only expounding his system of natural liberty to his students, but publicly asserting his claim to the authorship of that system in a Glasgow Economic Society—perhaps the first economic club established anywhere. The paper in which Smith vindicates this claim came somehow into the possession of Dugald Stewart, and so escaped the fire to which Smith committed all his other papers before his death, but it is believed to have been destroyed by Stewart's son, very possibly after his father's directions. For Stewart thought it would be improper to publish the complete manuscript, because it would revive personal differences which had better remain in oblivion, and consequently our knowledge of its contents is confined to the few sentences which he has thought right to quote as a valuable evidence of the progress of Smith's political ideas at that very early period. It will be observed that, as far as we can collect from so small a fragment of his discourse, he presents the doctrine of natural liberty in a more extreme form than it came to wear after twenty years more of thought in the Wealth of Nations. Stewart says that many of the most important opinions in the Wealth of Nations are detailed in this document, but he cites only the following:—
"Man is generally considered by statesmen and projectors as the materials of a sort of political mechanics. Projectors disturb nature in the course of her operations on human affairs, and it requires no more than to leave her alone and give her fair play in the pursuit of her ends that she may establish her own designs.... Little else is required to carry a state to the highest degree of affluence from the lowest barbarism but peace, easy taxes, and a tolerable administration of justice; all the rest being brought about by the natural course of things. All governments which thwart this natural course, which force things into another channel, or which endeavour to arrest the progress of society at a particular point, are unnatural, and, to support themselves, are obliged to be oppressive and tyrannical.... A great part of the opinions enumerated in this paper is treated of at length in some lectures which I have still by me, and which were written in the hand of a clerk who left my service six years ago. They have all of them been the constant subjects of my lectures since I first taught Mr. Craigie's class the first winter I spent in Glasgow down to this day without any considerable variations. They had all of them been the subjects of lectures which I read at Edinburgh the winter before I left it, and I can adduce innumerable witnesses both from that place and from this who will ascertain them sufficiently to be mine."[54]
The distinction drawn in the last sentence between that place, Edinburgh, and this place, shows that the paper was read to a society in Glasgow. Smith was a member of two societies there, of which I shall presently have something more to say, the Literary Society and a society which we may call the Economic, because it met for the discussion of economic subjects, though we do not know its precise name, if it had any. Now this paper of Smith's was not read to the Literary Society—at least, it is not included in the published list of papers read by it—and we may therefore conclude that it was read to the Economic Society.
Nothing is now known of the precise circumstances in which the paper originated, except what Stewart tells us, that Smith "was anxious to establish his exclusive right" to "certain leading principles both political and literary," "in order to prevent the possibility of some rival claims which he thought he had reason to apprehend, and to which his situation as a professor, added to his unreserved communications in private companies, rendered him peculiarly liable"; and that he expressed himself "with a good deal of that honest and indignant warmth which is perhaps unavoidable by a man who is conscious of the purity of his intentions when he suspects that advantages have been taken of the frankness of his temper." It would appear that some one, who had got hold of Smith's ideas through attending his class or frequenting his company, either had published them, or was believed to be going to publish them as his own.