value is not to depreciate,452 and he cannot be accused of the error of the mercantilists, that a country is impoverished by the export of money.453 He must also have understood clearly the importance of stability of value in a currency, since he deems it necessary to show that the increased output of silver will not decrease its value, and that silver is the least changeable of the monetary metals.454
Despite his enthusiasm for his thesis, which causes him to exaggerate the stability of silver, he does not fail to grasp the direct effect of supply and demand upon it,455 just as upon gold456 and other commodities.457
He shows also some understanding of the quantitative theory of the relation between gold and silver.458
It need hardly be added that, in strong contrast to Plato, his attitude toward the precious metals, especially silver, is very favorable.459