in the same ratio. The one is still a geometrical and the other
an arithmetical ratio, that is, one increases by multiplication,
and the other by addition. Where there are few people, and a
great quantity of fertile land, the power of the earth to afford
a yearly increase of food may be compared to a great reservoir of
water, supplied by a moderate stream. The faster population
increases, the more help will be got to draw off the water, and
consequently an increasing quantity will be taken every year. But
the sooner, undoubtedly, will the reservoir be exhausted, and the
streams only remain. When acre has been added to acre, till all
the fertile land is occupied, the yearly increase of food will
depend upon the amelioration of the land already in possession;
and even this moderate stream will be gradually diminishing. But
population, could it be supplied with food, would go on with
unexhausted vigour, and the increase of one period would furnish
the power of a greater increase the next, and this without any
limit.)

These facts seem to shew that population increases exactly in
the proportion that the two great checks to it, misery and vice,
are removed, and that there is not a truer criterion of the
happiness and innocence of a people than the rapidity of their
increase. The unwholesomeness of towns, to which some persons are
necessarily driven from the nature of their trades, must be
considered as a species of misery, and every the slightest check
to marriage, from a prospect of the difficulty of maintaining a
family, may be fairly classed under the same head. In short it is
difficult to conceive any check to population which does not come
under the description of some species of misery or vice.