Of course I do not pretend that they have the same force as if they represented the value of the ox everywhere in one particular epoch, or as if we had found the ox directly equated to gold in every case. But on the other hand the persistency of prices in semi-civilized countries is a fact well known: for example, prices have changed but very slightly in India38 during a long course of years, for although the silver rupee has sunk to about two-thirds of its nominal value in exchanges for gold, it purchases as much as ever in India. It is likely therefore that the conventional value of the ox would have remained unchanged for a long period of time, and the fact that our approximate values taken from various countries and from various centuries so closely coincide is a strong indication that such was the case.
Savages are still more conservative in their ideas of the relative value of certain articles; and when once a standard price has been fixed for certain commodities, it is almost impossible to get them to change.
Thus I am told by Mr W. H. Caldwell that, when he gave half-a-crown to a Queensland black for the first specimen of a certain kind of animal brought into camp, henceforth he had to pay the same amount for every specimen, even when they came in considerable numbers. So with the early men of Asia and Europe who first possessed cattle, and later on gold. Once a certain amount of gold was taken as the recognized value of a cow of certain age, the idea would become strongly rooted that so much gold was the proper equivalent of a cow. And it would only be in the lapse of centuries and with the development of cities and general commerce that the price of cattle would begin to fluctuate.
But even when such variation in price arose, it made no difference as regards the weight standard. The unit had already long been fixed and it remained unaltered, just as the beaver skin of account still means only two shillings, although a real beaver skin is now worth many times that amount.