of labour (or wages) does not vary much from year to year, though it does from generation to generation. On other occasions he speaks as if labour were intrinsically the most proper measure of value, on the ground that one day's ordinary muscular exertion of one man, may be looked upon as always, to him, the same amount of effort or sacrifice. But this proposition, whether in itself admissible or not, discards the idea of exchange value altogether, substituting a totally different idea, more analogous to value in use. If a day's labour will purchase in America twice as much of ordinary consumable articles as in England, it seems a vain subtlety to insist on saying that labour is of the same value in both countries, and that it is the value of the other things which is different. Labour, in this case, may be correctly said to be twice as valuable, both in the market and to the labourer himself, in America as in England.
If the object were to obtain an approximate measure by which to estimate value in use, perhaps nothing better could be chosen than one day's subsistence of an average man, reckoned in the ordinary food consumed by the class of unskilled labourers. If in any country a pound of maize flour will support a labouring man for a day, a thing might be deemed more or less valuable in proportion to the number of pounds of maize flour it exchanged for. If one thing, either by itself or by what it would purchase, could maintain a labouring man for a day, and another could maintain him for a week, there would be some reason in saying that the one was worth, for ordinary human uses, seven times as much as the other. But this would not measure the worth of the thing to its possessor for his own purposes, which might be greater to any amount, though it could not be less, than the worth of the food which the thing would purchase.
The idea of a Measure of Value must not be confounded with the idea of the regulator, or determining principle, of value. When it is said by Ricardo and others, that the value of a thing is regulated by quantity of labour, they do not
