Cotton Gin Patented

March 14, 1794:

 Eli Whitney is granted a patent for the cotton gin. A cotton gin (short for cotton engine) is a machine that quickly and easily separates cotton fibers from their seeds, a job that otherwise must be performed painstakingly by hand. The fibers are processed into cotton goods, and the seeds may be used to grow more cotton or to produce cottonseed oil; if they are badly damaged, they are disposed of.
The first modern mechanical cotton gin was created by American inventor Eli Whitney in 1793 and patented in 1794. It used a combination of a wire screen and small wire hooks to pull the cotton through, while brushes continuously removed the loose cotton lint to prevent jams. Larger, more complex, automated cotton gins remain a crucial part of the cotton industry today.

It might have been beneficial to the south, but it led directly to the Civil War:

Prior to the introduction of the mechanical cotton gin, cotton had required considerable labor to clean and separate the fibers from the seeds. With Eli Whitney’s introduction of “teeth” in his cotton gin to comb out the cotton and separate the seeds, cotton became a tremendously profitable business, creating many fortunes in the Antebellum South. New Orleans and Galveston were shipping points that derived substantial economic benefit from cotton raised throughout the South. Additionally, the greatly expanded supply of cotton created strong demand for textile machinery and improved machine designs that replaced wooden parts with metal. This led to the invention of many machine tools in the early 19th century.
The invention of the cotton gin caused massive growth in the production of cotton in the United States, concentrated mostly in the South. Cotton production expanded from 750,000 bales in 1830 to 2.85 million bales in 1850. As a result, the South became even more dependent on plantations and slavery, with plantation agriculture becoming the largest sector of the Southern economy.  The number of slaves rose in concert with the increase in cotton production, increasing from around 700,000 in 1790 to around 3.2 million in 1850.  By 1860, the southern states were providing two-thirds of the world’s supply of cotton, and up to eighty percent of the crucial British market.

Have I mentioned that I really don't like the South?