before that invention the United States exported less than one
hundred and forty thousand pounds of cotton; the year after it,
nearly half a million pounds; the next year over a million and a
half; a year later still, over six million; by 1800, nearly
eighteen million pounds a year. And by 1845 the United States was
producing producing seven-eighths of the world's cotton. Today
the United States produces six to eight billion pounds of cotton
annually, and ninety-nine per cent of this is the upland or
green-seed cotton, which is cleaned on the Whitney type of gin
and was first made commercially available by Whitney's
invention.*

* Roe, "English and American Tool Builders", pp. 150-51.


More than half of this enormous crop is still exported in spite
of the great demand at home. Cotton became and has continued to
be the greatest single export of the United States. In ordinary
years its value is greater than the combined value of the three
next largest exports. It is on cotton that the United States has
depended for the payment of its trade balance to Europe.

Other momentous results followed on the invention of the cotton
gin. In 1793 slavery seemed a dying institution, North and South.
Conditions of soil and climate made slavery unprofitable in the
North. On many of the indigo, rice, and tobacco plantations in
the South there were more slaves than could be profitably
employed, and many planters were thinking of emancipating their
slaves, when along came this simple but wonderful machine and
with it the vision of great riches in cotton; for while slaves