Sometimes the smallest invention can have an enormous impact far beyond anything ever imagine by its inventor. That was certainly the case when Eli Whitney invented the cotton gin. His invention made cotton a more economically viable cash crop and insured that the economy of the Southern states continued to rely on slavery. Thus, Eli Whitney probably more responsible for setting up the circumstances for the Civil War than many of the Presidents that served during his lifetime.
The invention of the cotton gin began with a chance encounter on a ship. Whitney needed money to attend Yale, so he traveled to South Carolina to be a private tutor. It just so happened that the widow of the Revolutionary war hero Nathaniel Greene was on the ship also. She invited Whitney to visit her at her plantation in Georgia. Georgia was a place where many Northerners at that time went to seek their fortunes, so Whitney decided to continue on to Georgia instead of stopping in South Carolina.
While at the Greene plantation, Whitney began thinking of some way to make cotton production more efficient. At that time, cotton was an extremely labor intensive crop. Not only did it have to be picked, but it had to be deseeded before it could be sold. That meant that not only did you have to have slaves to pick the cotton, but you had to have slaves pull the seeds out one at a time. Obviously, that took quite a while.
The story goes that Whitney invented the cotton gin when he saw a cat trying to pull a chicken through a fence. The chicken would not fit, however, so the cat only got some feathers. Whitney realized that if could invent a device to do something similar for cotton, it would take much less time to deseed cotton.
The device he invented was a wooden drum with hooks that pulled the cotton through a mesh. The seeds could not fit, however, so they were separated. Using this device, Whitney could deseed fifty-five pounds of cotton per day. This was much more cotton than a slave could deseed by hand in the same amount of time.
Whitney received a patent for his invention in 1794, but he did not market it well. Instead of selling his gins, he tried to make people pay him to use his while he took 40% of the profits. Obviously, few people were willing to do this, so many imitators came out with similar products. He went out of business just three years later.
The cotton gin had an enormous effect on the cotton industry. It made cotton a more viable cash crop, making it "King" in the south. Thanks to the new invention, cotton was so profitable that much of the economic production of the South became dependent upon it. That meant that they were also dependent upon the institution of slavery. Plantation owners needed slaves to pick the cotton from their enormous fields, so they needed to protect the institution of slavery to preserve their economic system. Thus, they became increasingly hostile to Northern attempts to regulate slavery.
This reliance on cotton production also had some other effects on the South. It depleted nutrients from the soil, making large sections of the South less fertile over time. It also kept the South more agricultural than the North which was beginning to industrialize in the early 19th century. This would make a difference during the Civil War.