_Standards of value._--More important still in the machinery of exchange is a standard unit of value. We have seen that value in any article of commerce can be fixed in terms of any other article, but prices remain indefinite so long as there is want of universal appreciation or appraisal in essentially the same terms and ideas. The tendency toward definite prices in well understood units of value is as clearly perceptible in the progress of commerce as is the tendency toward definiteness in weights and measures.
In early ages almost any article of common use, so that its qualities might be generally understood, has served as a standard of value, in terms of which all wealth has been estimated. Communities engaged in grazing counted all their wealth by cattle. Homer's heroes wore armor valued in cattle, and early Roman coins bore the images of cattle, while the very name of Roman coins, _pecunia_, is supposed to have been derived from the name of the flock. Communities of fishermen for a long period have estimated wealth in dried fish. More mechanical peoples have used some article of manufacture, like nails in some Scottish villages and the country cloth of western Africa. Sometimes a single prime article of export has served the purpose, like tobacco in the colony of Virginia and dried hides on the plains of South America. In most of pioneer America the hunters' pelts have served the same purpose, the average "coonskin" having a value which all could understand. As communities became more wealthy the display of wealth in ornaments made of precious metals and in precious stones has led to the use of these as standards of value. American Indians used their wampum, and African tribes employed peculiar shells. But as commerce increased, embracing wider regions, gold and silver became the staple article of value everywhere, since these, so easily tested for purity, could have their value estimated definitely by weight. Thus the standard unit of value has been definitely connected with standard weights.
_Coinage._--Gradually these weights, for greater ease of transfer and for clearer understanding of values, became the basis of coinage. The stamp of the coiner became a certificate of quality and quantity, and finally, as in the case of weights and measures, governments assumed the whole responsibility for fixing the weight and fineness of coins, and reduced all coinage to system, that every citizen might know the value of the unit in which he estimates any article of commerce.