In a state therefore of great equality and virtue, where pure
and simple manners prevailed, and where the means of subsistence
were so abundant that no part of the society could have any fears
about providing amply for a family, the power of population being
left to exert itself unchecked, the increase of the human species
would evidently be much greater than any increase that has been
hitherto known.

In the United States of America, where the means of
subsistence have been more ample, the manners of the people more
pure, and consequently the checks to early marriages fewer, than
in any of the modern states of Europe, the population has been
found to double itself in twenty-five years.

This ratio of increase, though short of the utmost power of
population, yet as the result of actual experience, we will take
as our rule, and say, that population, when unchecked, goes on
doubling itself every twenty-five years or increases in a
geometrical ratio.

Let us now take any spot of earth, this Island for instance,
and see in what ratio the subsistence it affords can be supposed
to increase. We will begin with it under its present state of
cultivation.

If I allow that by the best possible policy, by breaking up
more land and by great encouragements to agriculture, the produce
of this Island may be doubled in the first twenty-five years, I
think it will be allowing as much as any person can well demand.