by
emigration from Europe.

Emigration has certainly had some effect in increasing the population of
the United States. But so great has the rate of that increase been that,
after making full allowance for the effect of emigration, there will be
a residue, attributable to procreation alone, amply sufficient to double
the population in twenty-five years.

Mr Sadler states the results of the four censuses as follows:--

"There were, of white inhabitants, in the whole of the United States in
1790, 3,093,111; in 1800, 4,309,656; in 1810, 5,862,093; and in 1820,
7,861,710. The increase, in the first term, being 39 per cent.; that in
the second, 36 per cent.; and that in the third and last, 33 per cent.
It is superfluous to say, that it is utterly impossible to deduce
the geometric theory of human increase, whatever be the period of
duplication, from such terms as these."

Mr Sadler is a bad arithmetician. The increase in the last term is
not as he states it, 33 per cent., but more than 34 per cent. Now, an
increase of 32 per cent. in ten years, is more than sufficient to double
the population in twenty-five years. And there is, we think, very strong
reason to believe that the white population of the United States does
increase by 32 per cent. every ten years.

Our reason is this. There is in the United States a class of persons
whose numbers are not increased by emigration,--the negro slaves. During
the interval which elapsed between the census of 1810 and the census
of 1820, the change in their numbers must have been produced by
procreation, and by procreation alone. Their situation, though much
happier than that of the wretched beings who cultivate the sugar
plantations of Trinidad and Demerara, cannot be supposed to be more
favourable to health and fecundity than that of free labourers. In
1810, the slave-trade had been but recently abolished; and there were
in consequence many more male than female slaves,--a circumstance, of
course, very unfavourable to procreation. Slaves are perpetually passing
into the class of freemen; but no freeman ever descends into servitude;
so that the census will not exhibit the whole effect of the procreation
which really takes place.

We find, by the census of 1810, that the number of slaves in the Union
was then 1,191,000. In 1820, they had increased to 1,538,000. That is
to say, in ten years, they had increased 29 per cent.--within three
per cent. of that rate of increase which wo