proprietor is in proportion, not to its absolute, but to what may be called its relative fertility, or to its superiority over other mines of the same kind.

If new mines were discovered as much superior to those of Potosi as they were superior to those Europe, the value of silver might be so much degraded as to render even the mines of Potosi not worth the working. Before the discovery of the Spanish West Indies, the most fertile mines in Europe may have afforded as great a rent to their proprietor as the richest mines in Peru do at present. Though the quantity of silver was much less, it might have exchanged for an equal quantity of other goods, and the proprietor’s share might have enabled him to purchase or command an equal quantity either of labour or of commodities. The value both of the produce and of the