(4.) “The wages of labor vary according to the small or great trust which must be reposed in the workmen. The wages of goldsmiths and jewelers are everywhere superior to those of many other workmen, not only of equal but of much superior ingenuity, on account of the precious materials with which they are intrusted.” The superiority of reward is not here the consequence of competition, but of its absence: not a compensation for disadvantages inherent in the employment, but an extra advantage; a kind of monopoly price, the effect not of a legal, but of what has been termed a natural monopoly. If all laborers were trustworthy, it would not be necessary to give extra pay to working goldsmiths on account of the trust. The degree of integrity required being supposed to be uncommon, those who can make it appear that they possess it are able to take advantage of the peculiarity, and obtain higher pay in proportion to its rarity. This same explanation of a natural monopoly applies exactly to the causes which give able executive managers, who watch over productive operations, the usually high rewards for labor under the name of “wages of superintendence.” If successful managers of cotton or woolen mills were as plentiful, in proportion to the demand for them, as ordinary artisans, in proportion to the demand for them, then the former would get no higher rewards than the latter. Able executive and business managers secure high wages solely on the ground—as explained above—of monopoly; that is, because their numbers, owing to natural causes, are few relatively to the demand for them in every industry in the land. (5.) Some employments require a much longer time to learn, and a much more expensive course of instruction, than others; and to this extent there is, as explained by Adam Smith, an inherent reason for their being more highly remunerated. Wages, consequently, must yield, over and above the ordinary amount, an annuity sufficient to repay these sums, with the common rate of profit, within the number of years [the laborer] can expect to live and be in working condition. But, independently of these or any other artificial monopolies, there is a natural monopoly in favor of skilled laborers against the unskilled, which makes the difference of reward exceed, sometimes in a manifold proportion, what is sufficient merely to equalize their advantages. But the fact that a course of instruction is required, of even a low degree of costliness, or that the laborer must be maintained for a considerable time from other sources, suffices everywhere to exclude the great body of the laboring people from the possibility of any such competition. Until lately, all employments which required even the humble education of reading and writing could be recruited only from a select class, the majority having had no opportunity of acquiring those attainments.