before, so much food for so much labour employed in the growth of food: the return is now, a greater quantity of food, for the same labour employed in producing cottons or hardware or some other commodity, to be given in exchange for food. The one improvement, like the other, throws back the decline of the productive power of labour by a certain distance: but in the one case as in the other, it immediately resumes its course; the tide which has receded, instantly begins to re-advance. It might seem, indeed, that when a country draws its supply of food from so wide a surface as the whole habitable globe, so little impression can be produced on that great expanse by any increase of mouths in one small corner of it, that the inhabitants of the country may double and treble their numbers, without feeling the effect in any increased tension of the springs of production, or any enhancement of the price of food throughout the world. But in this calculation several things are overlooked.
In the first place, the foreign regions from which corn can be imported do not comprise the whole globe, but those parts of it principally which are in the immediate neighbourhood of coasts or navigable rivers. The coast is the part of most countries which is earliest and most thickly peopled, and has seldom any food to spare. The chief source of supply, therefore, is the strip of country along the banks of some navigable river, as the Nile, the Vistula, or the Mississippi; and of such there is not, in the productive regions of the earth, so great a multitude as to suffice during an indefinite time for a rapidly growing demand, without an increasing strain on the productive powers of the soil. To obtain auxiliary supplies of corn from the interior in any abundance, is, in the existing state of the communications, in most cases impracticable. By improved roads, and by canals and railways, the obstacle will eventually be so reduced as not to be insuperable: but this is a slow progress; in all the food-exporting countries except America, a very slow progress; and one which cannot keep pace with population, unless the increase of the last is very effectually restrained.
