Instruments of Trade Quotes in The Wealth of Nations
Every fixed capital is both originally derived from, and requires to be continually supported by, a circulating capital. All useful machines and instruments of trade are originally derived from a circulating capital, which furnishes the materials of which they are made, and the maintenance of the workmen who make them. They require, too, a capital of the same kind to keep them in constant repair.
No fixed capital can yield any revenue but by means of a circulating capital. The most useful machines and instruments of trade will produce nothing, without the circulating capital, which affords the materials they are employed upon, and the maintenance of the workmen who employ them. Land, however improved, will yield no revenue without a circulating capital, which maintains the labourers who cultivate and collect its produce.