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]