354 The principle of the division of labor was known to the ancients: _Xenophon_, Cyri Discipl., VIII, 2, 5. _Plato_, de Rep., II, 369, III, 394, IV, 443; _Isocrat_., Busir., 8. _Aristot_., Polit., II, 8, 8. Among the more modern writers, compare _Thomas Aquin_., De Reg. pr., I, 1, II, 3. _Luther_ (Works by Walch, I, 388), in his Commentary on Genesis, 3, 19. _Petty_, Several Essays, 1682, p. 113. Considerations upon the East India Trade, London, 1701. _Roscher_, Geschichte der englischen Volkswirthschaftslehre, 118. _Mandeville_, The Fable of the Bees, enlarged edition of 1723, p. 411. _Berkeley_, Querist, 1735, No. 415, 430, 520 ff., 586: “What is everybody’s business is nobody’s.” _Harris_, on Money and Coins (1757), I, 16. _J. J. Rousseau_, Emile (1762), L. III. _Turgot_, Sur la Formation et la Distribution des Richesses, § 3, p. 50, 62, 66. _Diderot_, Encyclopédie de l’Art, s. v. Art. _J. Tucker_, Four Tracts (1774), p. 25 ff. _Boccaria_, Economia pubblica, I, 1, 9. But the author to whom we owe most on this score is undoubtedly _Adam Smith_. To him we are indebted almost entirely for our knowledge of the natural laws developed in § 59 seq. 355 According to _Adam Smith_, a nailer can make 2,300 nails (_Rau_ says 3,000 shoemaker’s tacks in the Odenwalde) per day; a smith who is only occasionally employed in the manufacture, from 800 to 1,000; and smiths who never made nails before, from 200 to 300. A clever filer makes 200 strokes in a minute; a skilled comb-maker can make in a day from 60 to 70 combs of such fineness that there are from 40 to 48 teeth to the inch in them; eight Liege brick-makers, working together, produce 4,800 bricks per day; children employed in a needle manufactory, in making the eyes of needles, grow so skillful at it that they can make a small hole in the finest hair and draw another hair through it. _Rau_, Lehrbuch I, § 115. The old proverb, “practice makes perfect,” is followed even by thieves in their great division of labor. See _Thiele_, Die jüdischen Gauner I, 87. _Fregier_, Des Classes Dangéreuses. 356 Children, with their thinner fingers, can point twice as many needles in the same time as a grown person. 357 The manufacture of English needles demands, on the part of workmen, degrees of skill so different that their pay varies from 6 pence to 20 shillings per day. If the most skillful workman were to manufacture whole needles alone, he would partly be obliged to be satisfied with one-fortieth of what he might otherwise receive. _Babbage_, loc. cit. 358 In the case of machines and in the chemical branches of industry, the labor increases in a much smaller ratio than the material used in production.