The establishment of trade and industry naturally rectifies this misapplication of agriculture, by purging the land of superfluous mouths, and thereby reduces it, as it ought to be, to a trade calculated to furnish a surplus, which comes to be sold for the labour of all the industrious. It is this alone which can rivet the bond of general dependence among free men who must live by their industry; by making one part laborious farmers, and the other ingenious tradesmen and manufacturers. It is by the vibration of the balance between these two classes, that multiplication and agriculture are carried to their height. When industry goes on too fast, free hands multiply above the standard, that is, their scale sinks; this raises the price of food, and gives an additional encouragement to agriculture: when this again becomes the more weighty, food becomes plentiful and cheap, then numbers augment a-new. These reflections lead me to consider the effects of plentiful and scarce years in modern times, when famines are almost things unknown; and I conclude, [Sidenote: CHAP. XVII.] That were plentiful years more common, mankind would be more numerous; that were scarce years more frequent, numbers would diminish. Then applying this observation to the state of exportations of grain from England, I am tempted to infer, that this kingdom, the most fertile perhaps in Europe, has never been found to produce, in one year, eighteen months full subsistence for all its inhabitants; nor ever less than ten months scanty provision in the years of the greatest sterility. [Sidenote: CHAP. XVIII.] When a country is fully peopled and continues to be industrious, food will come from abroad. When a loaf is to be had, the rich will eat it, though at the distance of a mile; and the poor may starve, though at the next door. It is the demand of the rich, who multiply as much as they incline, which encourages agriculture even in foreign nations; therefore I conclude, that this multiplication is the cause, and that the progress of agriculture is but the effect of it. A country once fully stocked may diminish in numbers, and still remain stocked. This must proceed from a change in the manner of living; as when an indolent people quit the consumption of the more abundant productions of the earth, to seek after delicacies. On the other hand, the industrious bring an additional supply from abroad, and by furnishing strangers with the produce of their labour, they still go on and increase in numbers. This is the case of Holland: and this scheme will go on, until abuses at home raise the price of labour; and experience abroad, that universal school mistress, teaches foreigners to profit of their own advantages. When food ceases to be augmented, numbers come to a stand; but trade may still go on and increase wealth: this will hire armies of foreigners; so the traders may read of their own battles, victories, and trophies, and by spending their money, never smell gunpowder.