POLITICAL ECONOMY 667 1691). Among the doctrines held by him as fundamental were : " That the whole world as to trade is but as one nation ; that money is a merchandise whereof there may be a glut as well as scarcity, and that even to an inconve- nience ; that a people cannot want money to serve the ordinary dealing, and more than enough they will not have ; and that money exported in trade is an increase to the wealth of a nation." Sir William Petty, in " Quantu- lumcunque, or a Tract concerning Money," had in 1682 attacked the theory of u the balance of trade;" and at a subsequent day there were many champions on both sides of this vexed question; among others, Dr. Davenant (1695- 1712) and the Rev. Josiah Tucker (1753), who espoused the so-called mercantile theory, and Sir Matthew Decker (1744) and Joseph Harris (1757-'8), who opposed it. In 1698 appeared in London " Historical and Political Essays, or Discourses on Several Subjects," including money, government, &c., by John Locke, com- prising papers which had been previously pub- lished, in which he had for the first time pro- mulgated some of the favorite theories in re- gard to money now held by European econo- mists. He taught that men in their bargains contract " not for denominations or sounds, but for the intrinsic value, which is the quantity of silver by public authority warranted to be in pieces of such denominations;" and further, that " one metal alone can be the money of ac- count and contract, and the measure of com- merce in any country ; ... all other metals, gold as well as lead, are but commodities." In 1758 appeared at Versailles the Tableau econo- mique, et maximes generates du gouvernement econom.ique, by Francois Quesnay, followed by Theorie de Vimpot, by the elder Mirabeau (1760), La philosophic rurale, also by Mira- beau (1763), and various other works by Ques- nay and his disciples, expounding the physio- cratic or agricultural system of economy. The physiocratists held that the earth is the sole producer of wealth, and divided the industrial members of society into three classes : 1, the proprietors of the land; 2, the cultivators, whom they regarded as a productive class ; 3, the mechanics, manufacturers, and merchants, whom they styled the unproductive class. That portion of his income which the landlord laid out in the improvement of his land they char- acterized as productive expenses ; and in so far as the landlord by these expenditures aided the farmer in increasing the amount of his produce, the landlord became one of the productive class. They maintained that the labor of mechanics, manufacturers, and artisans was unproductive, because it merely replaced the stock which employed them, together with the ordinary profits of that stock ; and that mercantile stock j was unproductive because it merely continued j the existence of its own value. They admitted that mechanics, manufacturers, and merchants might augment the revenue and wealth of so- eiety, but that it could only be accomplished by parsimony or privation. They believed that the most perfect freedom of trade with all na- tions was the great desideratum for agricul- ture. Dissenting entirely from the central idea of this school and its logical deductions, Adam Smith, in 1776, expressed the opinion that u with all its imperfections it is, perhaps, the nearest approximation to the truth that has yet been published upon the subject of political economy." Among the most eminent of the physiocratists was Turgot, afterward comptrol- ler general of finances, who early embraced the views of Quesnay, and in 1771 published Re- flexions sur la formation et la distribution det> richesses, the ablest of the treatises of this school. A Spanish treatise well worthy of at- tention is " The Theory and Practice of Com- merce and Maritime Affairs," by Geronimo de Ustariz (Madrid, 1724; English, 2 vols., 1751). " Though imbued with the prejudices of the mercantile system," says McCulloch, "it is valuable for the information it affords re- specting the internal policy, trade, and state of Spain from the reign of Charles V. down- ward." Montesquieu's De V esprit des low (Ge- neva, 1748) is worthy of note in the history of political economy, on account of its refer- ence to such subjects, particularly in regard to foreign commerce, taxes, public debts, and money. His theory of money very closely re- sembles the views of Hume upon the subject, which are now held by so many economists. Among the contributions to political econ- omy up to the end of the 18th century, none evince greater reasoning power than the " Po- litical Discourses " of David Hume (1752). Among those essays which come within the limit of political economy are " Commerce," "Refinements in the Arts," "Money," "Inter- est," "The Balance of Trade," "The Jealousy of Trade," " Taxes," and " Public Credit," Ac- cording to the doctrines of these essays, every- thing in the world is purchased by labor, and our passions are the only causes of labor; when a nation abounds in manufactures and the mechanic arts, scientific agriculture becomes possible, and the cultivators of the soil redouble their industry and attention, the surplus pro- duce being readily exchanged for the products of those manufactures and mechanic arts, and the land furnishes more than is needed for the support of those who cultivate it ; while on the other hand, where this diversified industry does not flourish, therie is no inducement for the agriculturists to increase their skill and industry, because of the difficulty of exchanging any surplus. Foreign trade by its imports fur- nishes raw materials for new manufactures, and by its exports gives employment to labor, which in the absence of this trade might be wasted. Necessity is the great incentive to industry and invention rather the fears than the hopes, the aspirations, and the ambition of mankind. Money Hume considers not properly one of the subjects of commerce, but " only the instrument which men have agreed upon