THE WEALTH OF NATIONS.

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the quantity either of labour or of any other commodity whichcan be had in exchange for it.

Gold and silver, however, like every other commodity,vary in their value, are sometimes cheaper and some-timesdearer, sometimes of easier and sometimes of more difficultpurchase. The quantity of labour which any particular quan-tity of them can purchase or command, or the- quantity ofother goods which it will exchange for, depends always uponthe fertility or barrenness of the mines which happen to beknown about the time when such exchanges are made. Thediscovery of the abundant mines of America reduced, in thesixteenth century, the value of gold and silver in Europe toabout a third of what it had been before. As it cost lesslabour to bring those metals from the mine to the market, sowhen they were brought thither they could purchase or com-mand less labour; and this revolution in their value, thoughperhaps the greatest, is by no means the only one of whichhistory gives some account. But as a measure of quantity,such as the natural foot, fathom, or handful, which is con-tinually varying in its own quantity, can never be an accu-rate measure of the quantity of other things; so a commo-dity which is itself continually varying in its own value cannever be an accurate measure of the value of other commo-dities. Equal quantities of labour, at all times and places^may be said to be of equal value to the labourer. In his or-dinary state of health, strength, and spirits; in the ordinarydegree of his skill and dexterity, he must always lay dowijithe same portion of his ease, his liberty, and his happiness-.The price which he pays must always be the same, whatevermay be the quantity of goods which he receives in returnfor it. Of these, indeed, it may sometimes purchase a greaterand sometimes a smaller quantity; but it is their value whichvaries, not that of the labour which purchases them. Atall times and places that is dear which it is difficult to comeat, or which it costs much labour to acquire; and that cheapwhich is to be had easily, or with very little labour, ^.abour,alone, therefore, never varying in its own value, is alone theultimate and real standard by which the value of all com-modities can at all times and places be estimated and com-s i pared. It is their real price; money is their nominal price

only.

But though equal quantities of labour are always of equalvalue to the labourer, yet to the person who employs him they

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