Cotton gin.
The cotton gin or cotton engine is a device used to separate cotton fibers from seeds. Prior to the invention of the cotton gin by the Connecticut inventor Eli Whitney in 1793, separating cotton fibers from seeds was a labor-intensive process that produced one pound of cotton fiber per day. Whitney's cotton gin, which used metal hooks to pull cotton fibers through a wire mesh that seeds were too large to pass through, increased the production of cotton fiber to 55 pounds per day.
Thanks to the breakthrough produced by the cotton gin, cotton went from being a marginal agricultural product to the most lucrative agricultural product in the Southern Confederation and Jefferson. In Jefferson cotton production rose from less than 1,000 bales in 1793 to over 30,000 in 1800. In the S.C., cotton production rose from 15,000 bales in 1793 to 60,000 in 1798 to 180,000 in 1810 to 998,000 in 1835. Two years later, as cotton production began to fall in the S.C., the amount produced in Jefferson outpaced that of the S.C.
As cotton production rose, so did the importation of Negro slaves to work the cotton fields. In Jefferson slavery had been almost extinct in 1793, but by 1800 there were 34,000 Negro slaves alongside a population of 65,000 free whites. In the S.C., the number of slaves rose from 590,000 in 1810 to 1,449,000 in 1837 even as the free white population rose from 2,998,000 to 5,369,000.
The cotton boom in both places ended with the Panic of 1836. Although the resulting economic slump had ended by the early 1840s, by then the disruptions of the Rocky Mountain War and competition from Egypt and India made cotton cultivation less profitable, and the economies of both Jefferson and the Southern Confederation became more diversified.