Two employees of the Holmes Gin Company collect some cotton that overflowed from the gin machine. Whitney's cotton gin is only one of his inventions that reshaped American industry.

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We sometimes fault machines for taking people's jobs, but some actually create them. Technology can boost productivity, which increases the demand for labor. It can also streamline complex tasks, opening the door for less skilled workers. American inventor Eli Whitney devised innovations that did both. Through his inventions, he transformed America's antebellum North and South, inadvertently setting them on a road toward conflict while helping America become more prosperous.

Whitney's most famous invention, the modern "saw" cotton gin was patented in 1794. The word "gin" is short for "engine," and it revolutionized cotton production in the South by automating its processing. His device consisted of a set of wheels on an axle attached to a crank. Each wheel sported metal hooks, akin to circular saw blades. As the blades turned, the metal hooks caught bits of cotton, pulling them through a screen that kept out seeds and hulls. A wire brush periodically swept the cotton off the blade as it came around, preventing the machine from jamming.

The cotton gin was especially useful to inland cotton farmers, who could only cultivate "green seed" cotton. This cotton was so labor-intensive that it required 10 arduous hours of hand labor to produce a single unit of useful "lint cotton." One Whitney cotton gin could do the day's work of several men in an hour.

Although it was a laborsaving device, the cotton gin strengthened slavery. The southern states bought more slaves to meet the ensuing productivity boost. Cotton was once a crop too labor-intensive for any but the largest plantations to produce. But the cotton gin helped it spread throughout the South. Raw cotton yield doubled each decade after 1800 until America supplied three-quarters of the world's cotton by the middle of the century.

Ironically, although the American South became a global cotton powerhouse because of the cotton gin, Whitney went broke fighting more than 60 lawsuits to defend his patent against copies. He was so discouraged that he never tried to patent his inventions again. As he put it, "An invention can be so valuable as to be worthless to the inventor."

Desperate for money, and with the U.S. possibly facing a war with France, Whitney sought and won a contract from the War Department to produce 10,000 to 15,000 muskets in only two years. This was quite a feat for a man with no firearms manufacturing experience. Trying to meet his ambitious contract led to his other great inventions, which helped set the stage for the Industrial Revolution in America. Whitney's inventions made him one of the fathers of American mass production.