CHAPTER II.

for one pound of silver, seems by no means incredible. But as the productive powers of labor in society are developed and the product of unskilled labor rises in value as compared with the product of skilled labor; as the earth’s crust is more thoroughly broken up and the original superficial sources of gold supply give out, the value of silver begins to fall in proportion to that of gold. At a given stage of development of engineering and of the means of communication, the discovery of new gold or silver fields become the decisive factor. In ancient Asia the ratio of gold to silver was 6 to 1 or 8 to 1; the latter ratio prevailed in China and Japan as late as the beginning of the nineteenth century; 10 to 1, the ratio in Xenophon’s time, may be considered as the average ratio of the middle period of antiquity. The exploitation of the Spanish silver mines by Carthage and later by Rome had about the same effect in antiquity, as the discovery of the American mines in modern Europe. For the period of the Roman empire 15 or