A comparative study of the writings and characters of Petty and Boisguillebert, outside of the light which it would throw upon the difference of French and English society at the end of the seventeenth and the beginning of the eighteenth centuries, would disclose the origin of the national contrast between English and French Political Economy. The same contrast reasserts itself in Ricardo and Sismondi.

Petty had illustrated the productive power inherent in the division of labor on a much grander scale than that was done later by Adam Smith. See his “Essay concerning the multiplication of mankind, etc.,” 3rd edition, 1686, p. 35-36. He not only brings out the advantages of the division of labor on the example of the manufacture of a watch, as Adam Smith did later on that of a needle, but considers also a city and an entire country from the point of view of a large manufacturing establishment. The Spectator, of November 26, 1711, refers to this “illustration of the admirable Sir William Petty.” McCulloch is, therefore, mistaken when he supposes that the Spectator confounded Petty with a writer forty years his junior. See McCulloch, “The Literature of Political Economy, a classified catalogue,” London, 1845, p. 105. Petty is conscious of being the founder of a new science. His method, he says, “is not yet very usual, for instead of using only comparative and superlative Words, and intellectual Arguments,” he has undertaken to speak “in Terms of Number, Weight or Measure; to use only Arguments of Sense, and to consider only such Causes, as have visible Foundations in Nature; leaving those that depend upon the mutable Minds, Opinions, Appetites, and Passions of particular Men, to the Consideration of others.” (Political Arithmetick, etc., London, 1699.