That this is the way in which the increase of population powerfully acts in increasing rent, whoever, in a progressive country, will look around him, may see for himself. The process is going on under his eyes. The increasing difference in the productiveness of the land in use, which causes an increasing rise in rent, results not 80 much from the necessities of increased population compelling the resort to inferior land, as from the increased productiveness which increased population gives to the lands already in use. The most valuable lands on the globe, the lands which yield the highest rent, are not lands of surpassing natural fertility, but lands to which a surpassing utility has been given by the increase of population.
The increase of productiveness or utility which increase of population gives to certain lands, in the way to which I have been calling attention, attaches, as it were, to the mere quality of extension. The valuable quality of land that has become a center of population is its superficial capacity—it makes no difference whether it is fertile, alluvial soil like that of Philadelphia; rich bottom land like that of New Orleans; a filled-in marsh like that of St. Petersburg, or a sandy waste like the greater part of San Francisco.
And where value seems to arise from superior natural qualities, such as deep water and good anchorage, rich deposits of coal and iron, or heavy timber, observation also shows that these superior qualities are brought out, rendered tangible, by population. The coal and iron fields of Pennsylvania, that to-day are worth enormous sums, were fifty years ago valueless. What is the efficient cause of the difference? Simply the difference in population. The coal and iron beds of Wyoming and Montana, which to-day are valueless, will, in fifty years from now, be worth millions on millions, simply because, in the meantime, population will have greatly increased.
