182 PROTECTION OK FKEE TRADE.
profits in protected industries can only be kept above those of unprotected industries by some sort of monopoly which shields them from home competition as the tariff does from foreign competition. The first effect of a protective duty is to increase profits in the protected industry. But unless that industry be in some way protected from the influx of competitors which such increased profits must attract, this influx must soon bring these profits to the general level. A monopoly, more or less complete, which may thus enable certain producers to retain for themselves the increased profits which it is the first effect of a protective duty to give, may arise from the possession of advantages of different kinds.
It may arise, in the first place, from the possession of some peculiar natural advantage. For instance, the only chrome mines yet discovered in the United States, belonging to a single family, that family have been much encouraged by the higher prices which the protective duty on chrome has enabled them to charge home consumers. In the same way, until the discovery of new and rich, copper deposits in Arizona and Montana the owners of the Lake Superior copper mines were enabled to make enormous dividends by the protective duty on copper, which, so long as home competition was impossible, shut out the only competition that could reduce their profits, and enabled them to get three or four cents more per pound for the copper they sold in the United States than for the copper they shipped to Europe.
Or a similar monopoly may be obtained by the possession of exclusive privileges given by the patent laws. For instance, the combination based on patents