All this, however, was the slow preparation for a newer and greater movement in political economy than had yet been known, and which laid the foundation of the modern study as it exists to-day. The previous discussions on money and the prominence given to agriculture and economic considerations by the Economists made possible the great achievements of Adam Smith and the English school. A reaction in England against the mercantile system produced a complete revolution in political economy. Vigorous protests against mercantilism had appeared long before,(24) and the true functions of money had come to be rightly understood.(25) More than that, many of the most important doctrines had been either discussed, or been given to the public in print. It is at least certain that hints of much that made so astonishing an effect in Adam Smith’s “Wealth of Nations” (1776) had been given to the world before the latter was written. To what sources, among the minor writers, he was most indebted, it is hard to say. Two, at least, deserve considerable attention, David Hume and Richard Cantillon. The former published his “Economic Essays” in 1752, which contained what even now would be considered enlightened views on money, interest, balance of trade, commerce, and taxation; and a personal friendship existed between Hume and Adam Smith dating back as far as 1748, when the latter was lecturing in Edinburgh on rhetoric. The extent of Cantillon’s acquirements and Adam Smith’s possible indebtedness to him have been but lately recognized. In a recent study(26) on Cantillon, the late Professor Jevons has pointed out that the former anticipated many of the doctrines later ascribed to Adam Smith, Malthus, and Ricardo. Certain it is that the author of the “Wealth of Nations” took the truth wherever he found it, received substantial suggestions from various sources, but, after having devoted himself in a peculiarly successful way to collecting facts, he wrought out of all he had gathered the first rounded system of political economy the world had yet known; which pointed out that labor was at the basis of production, not merely in agriculture, as the French school would have it, but in all industries; and which battered down all the defenses of the mediæval mercantile system. In a marked degree Adam Smith(27) combined a logical precision and a power of generalizing results out of confused data with a practical and intuitive regard for facts which are absolutely necessary for great achievements in the science of political economy. At Glasgow (1751-1764) Adam Smith gave lectures on natural theology, ethical philosophy, jurisprudence, and political economy, believing that these subjects were complementary to each other.