The subject therefore of the first chapter shall be, 1. To point out the principles which determine the value of things; 2. The use of an invariable scale to measure their value; 3. How the invention of money of account is exactly adapted for measuring the value on the one hand, and measuring the price on the other; and 4. How it preserves itself invariable amidst all the fluctuations, not only of the value of things themselves, but of the metals which are commonly considered as the measures of their value.
Money, a scale for measuring value.
1mo. Money of account, which I shall here call money, performs the same office with regard to the value of things, that degrees, minutes, seconds, &c. do with regard to angles, or as scales do to geographical maps, or to plans of any kind.
In all these inventions, there is constantly some denomination taken for the unit.
In angles, it is the degree; in geography, it is the mile, or league; in plans, the foot, yard, or toise; in money, it is the pound, livre, florin, &c.
The degree has no determinate length, so neither has that part of the scale upon plans which marks the unit: the usefulness of all those inventions being solely confined to the marking of proportion.
Just so the unit in money can have no invariable determinate proportion to any part of value, that is to say, it cannot be fixed to any particular quantity of gold, silver, or any other commodity whatsoever.
The unit once fixed, we can by multiplying it, ascend to the greatest value; and when we descend below the subaltern divisions of this unit, we have the assistance of measures and weights, which render the operation easy. Thus in England, where a farthing is the lowest denomination of money, the grains of wheat are bought by measure, and cherries by the pound.
Principles which determine the value of things.
II. The value of things depend upon the general combination of many circumstances, which however may be reduced to four principal heads: