Though we frequently, therefore, express a person’s revenue by the metal pieces which are annually paid to him, it is because the amount of those pieces regulates the extent of his power of purchasing, or the value of the goods which he can annually afford to consume. We still consider his revenue as consisting in this power of purchasing or consuming, and not in the pieces which convey it.
But if this is sufficiently evident, even with regard to an individual, it is still more so with regard to a society. The amount of the metal pieces which are annually paid to an individual, is often precisely equal to his revenue, and is upon that account the shortest and best expression of its value. But the amount of the metal pieces which circulate in a society, can never be equal to the revenue of all its members. As the same guinea which pays the weekly pension of one man to-day, may pay that of another to-morrow, and that of a third the day thereafter, the amount of the metal pieces which annually circulate in any country, must always be of much less value than the whole money pensions annually paid with them. But the power of purchasing, or the goods which can successively be bought with the whole of those money pensions, as they are successively paid, must always be precisely of the same value with those pensions; as must likewise be the revenue of the different persons to whom they are paid. That revenue, therefore, cannot consist in those metal pieces, of which the amount is so much inferior to its value, but in the power of purchasing, in the goods which can successively be bought with them as they circulate from hand to hand.
Money, therefore, the great wheel of circulation, the great instrument of commerce, like all other instruments of trade, though it makes a part, and a very valuable part, of the capital, makes no part of the revenue of the society to which it belongs; and though the metal pieces of which it is composed, in the course of their annual circulation, distribute to every man the revenue which properly belongs to him, they make themselves no part of that revenue.