the whole annual importation. As the water, however, must always be deeper behind the dam-head than before it, so the quantity of gold and silver which these restraints detain in Spain and Portugal must, in proportion to the annual produce of their land and labour, be greater than what is to be found in other countries.

The higher and stronger the dam-head, the greater must be the difference in the depth of water behind and before it. The higher the tax, the higher the penalties with which the prohibition is guarded, the more vigilant and severe the police which looks after the execution of the law, the greater must be the difference in the proportion of gold and silver to the annual produce of the land and labour of Spain and Portugal, and to that of other countries. It is said accordingly to be very considerable, and