“Suppose, he observes, that we had such a commodity as Mr. Ricardo requires for a standard: suppose, for instance, all commodities to be produced by labour alone, and silver to be produced by an invariable quantity of labour. In this case, silver would be, according to Mr. Ricardo, a perfect measure of value. But in what sense? What is the function performed? Silver, even if invariable in its producing labour, will tell us nothing of the value of other commodities. Their relations in value to silver, or their prices, must be ascertained in the usual way; and, when ascertained, we shall certainly know the values of commodities in relation to each other; but in all this, there is no assistance derived from the producing labour of silver being a constant quantity.”[75] I have already described the function which silver would have to perform in this case, namely, either to measure the different powers of purchasing possessed by commodities at different periods, or to measure the different degrees of estimation in which they were held at these different periods. Now, in the first place, with regard to the general power of purchasing, can it be denied for a moment, that, granting all the premises, as the author does hypothetically, silver, so produced, would be, beyond comparison, a better measure of the power of purchasing generally, than silver as it has been actually produced? It would be secured from that greatest source of variation in the general power of purchasing occasioned by the variation in its own producing labour; and an ounce of such silver would command much more nearly the same quantity of labour and commodities, for four or five hundred years together, than an ounce of silver derived from mines of greatly varying fertility. Secondly, with regard to the estimation in which a commodity is held, it is not easy to conceive a more complete measure. If all commodities were produced by labour alone, and exchanged with each other according to the producing labour; and if silver were produced by an invariable quantity of labour, the quantity of silver given for a commodity in the market at different periods, would express almost accurately the relative estimation in which it was held at these periods; because it would express at once the relative sacrifice which people were willing to make, in order to obtain such a commodity at these different periods; the relative conditions of the supply, or elementary costs of production, of such commodity at these periods; and the proportion of the produce to the producer, or the relative state of the demand, as compared with the supply of such commodity at these different periods. And if the value of a commodity means, as the author has told us in the first sentence of his book, the esteem in which it is held, Mr. Ricardo’s measure would certainly do all which he proposed it should do; and this specifically on account of its invariability in relation to the estimation in which it was held.