79. In comparing the value of money with that of commodities, we consider silver as a metal, which is an object of comme

In the market a measure of corn is purchased with a certain weight of silver, or a quantity of silver is bought with a certain commodity, it is this quantity which is valued and compared with the value of other commodities. In a loan upon interest, the object of the valuation is the use of a certain quantity of property during a certain time. It is in this case no longer a mass of silver, compared with a quantity of corn, but it is a portion of effects compared with a certain portion of the same, which is become the customary price of that mass for a certain time. Let twenty thousand ounces of silver be an equivalent in the market for twenty thousand measures of corn, or only for ten thousand, the use of those twenty thousand ounces of silver for a year is not worth less on a loan than the twentieth part of the principal sum, or one thousand ounces of silver, if interest is at five per cent.