Upon the dangerous question of religious establishments and dissenting sects he wrote afterwards in the _Wealth of Nations_ (Book v. i.) with a boldness and an air of detachment that might well startle even that age of tolerant indifference. He contrasts the teachers of new religions with the clergy of an ancient system, who are frequently possessed of learning, eloquence, and all the gentlemanly virtues. “Such a clergy, when attacked by a set of popular and bold though perhaps stupid and ignorant enthusiasts, feel themselves as perfectly defenceless as the indolent, effeminate, and full-fed nations of the southern parts of Asia, when they were invaded by the active, hardy, and hungry Tartars of the north.” Commonly, the only resource of such a clergy upon such an emergency is to summon the government to persecute or expel their adversaries. “It was thus that the Roman Catholic clergy called upon the civil magistrate to persecute the Protestants, and the Church of England to persecute the Dissenters.” An established church may have a superiority of learning, but in the art of gaining popularity the advantage is always with its adversaries. He finds that, as dissenting bodies grow richer, their zeal and activity abate. The Independents, for instance, had many learned, ingenious, and respectable men; but the Methodists, without half the learning of the Dissenters, were more in vogue. The strength of the Church of Rome he attributed to the fact that the industry of its inferior clergy was better fostered by motives of self-interest than in the case of any established Protestant church; for many of the parish priests subsisted largely on voluntary gifts, “a source of revenue which confession gives them many opportunities of improving.” He notes also Machiavelli’s observation, that the establishment of the begging orders of St. Dominic and St. Francis revived, in the thirteenth and fourteenth centuries, the languishing faith and devotion of the Catholic Church. Upon the question of the value of a State Church, Smith quotes from a certain passage of Hume’s _History_, referring to his friend as “by far the most illustrious philosopher and historian of the present age.” Hume had come to the conclusion that the civil magistrate who neglects to establish a religion will find he has dearly paid for his frugality, “and that in reality the most decent and advantageous composition which he can make with the spiritual guides, is to bribe their indolence by assigning stated salaries to their profession,” so that ecclesiastical establishments, “though commonly they arose at first from religious views, prove in the end advantageous to the political interests of society.”