As long as the new situation shall be _far_ preferable to the old [he said], the emigration may possibly continue. But when many of those, who at home interfered with others of the same rank (in the competition for farms, shops, business, offices, and other means of subsistence), are gradually withdrawn, the inconvenience of that competition ceases; the number remaining no longer half starve each other; they find they can now subsist comfortably, and though perhaps not quite so well as those who have left them, yet, the inbred attachment to a native country is sufficient to overbalance a moderate difference; and thus the emigration ceases naturally. The waters of the ocean may move in currents from one quarter of the globe to another, as they happen in some places to be accumulated, and in others diminished; but no law, beyond the law of gravity, is necessary to prevent their abandoning any coast entirely. Thus the different degrees of happiness of different countries and situations find, or rather make, their level by the flowing of people from one to another; and where that level is once found, the removals cease. Add to this, that even a real deficiency of people in any country, occasioned by a wasting war or pestilence, is speedily supplied by earlier and more prolific marriages, encouraged by the greater facility of obtaining the means of subsistence. So that a country half depopulated would soon be repeopled, till the means of subsistence were equalled by the population. All increase beyond that point must perish, or flow off into more favourable situations. Such overflowings there have been of mankind in all ages, or we should not now have had so many nations. But to apprehend absolute depopulation from that cause, and call for a law to prevent it, is calling for a law to stop the Thames, lest its waters, by what leave it daily at Gravesend, should be quite exhausted. Twenty-three years before he had stated the same truths more sententiously in his essay on the _Increase of Mankind_. In fine [he said in that essay] a Nation well regulated is like a Polypus; take away a Limb, its Place is soon supply'd; cut it in two, and each deficient Part shall speedily grow out of the Part remaining. Thus if you have Room and Subsistence enough, as you may by dividing, make ten Polypes out of one, you may of one make ten Nations, equally populous and powerful; or rather increase a Nation ten fold in Numbers and Strength.