After graduating from Yale, Eli Whitney left Massachusetts to become a private tutor on a plantation in Georgia. He realized that the southern planters were looking for a way to make cotton growing profitable. Cotton growing was highly regarded especially after tobacco declined in profits due to oversupply and soil exhaustion.
In a secret workshop provided by Catherine Greene, Whitney created the cotton gin. A small gin could be hand-cranked while larger versions could be harnessed to a horse or driven by water power. Whitney produced many gins which he would let the farmers use at a fee paid in cotton; two-fifths of the profit. This didn’t work well with most farmers. They felt the ‘tax’ was too much. They instead made their own gins.
After the invention of the cotton gin, the yield of raw cotton doubled each decade after 1800. Demand was fueled by other inventions of the Industrial Revolution, such as the machines to spin and weave it and the steamboat to transport it.
Slaves demand also increased. More people were required to plant and pick the cotton. Because of the gin, slaves now labored on even-larger plantations. As large plantations spread to the southwest, the prices of slaves and land inhibited the growth of cities and industries.
Source: The Cotton Gin
Eli Whitney Museum and Workshop, CC BY-NC-SA 3.0