As the efficacy of human industry, in increasing the quantity either of wool or of raw hides, is limited, so far as it depends upon the produce of the country where it is exerted; so it is uncertain so far as it depends upon the produce of other countries. It so far depends not so much upon the quantity which they produce, as upon that which they do not manufacture; and upon the restraints which they may or may not think proper to impose upon the exportation of this sort of rude produce. These circumstances, as they are altogether independent of domestic industry, so they necessarily render the efficacy of its efforts more or less uncertain. In multiplying this sort of rude produce, therefore, the efficacy of human industry is not only limited, but uncertain.
In multiplying another very important sort of rude produce, the quantity of fish that is brought to market, it is likewise both limited and uncertain. It is limited by the local situation of the country, by the proximity or distance of its different provinces from the sea, by the number of its lakes and rivers, and by what may be called the fertility or barrenness of those seas, lakes, and rivers, as to this sort of rude produce. As population increases, as the annual produce of the land and labour of the country grows greater and greater, there come to be more buyers of fish; and those buyers, too, have a greater quantity and variety of other goods, or, what is the same thing, the price of a greater quantity and variety of other goods, to buy with. But it will generally be impossible to supply the great and extended market, without employing a quantity of labour greater than in proportion to what had been requisite for supplying the narrow and confined one. A market which, from requiring only one thousand, comes to require annually ten thousand ton of fish, can seldom be supplied, without employing more than ten times the quantity of labour which had before been sufficient to supply it. The fish must generally be sought for at a greater distance, larger vessels must be employed, and more expensive machinery of every kind made use of. The real price of this commodity, therefore, naturally rises in the progress of improvement. It has accordingly done so, I believe, more or less in every country.