When he was studying law, he lived in Mrs. Green's house and introduced him to some gentlemen who cared about the cotton industry. For the south, cotton is a rich thing, but it is very difficult to separate cotton fiber from cottonseed. But Whitney thinks it's easy to make a device with a metal hook to finish the job. 1793 in April, he invented the cotton gin, that is, the metal hook teeth passed through the slats, wrapped the cotton fibers, and finally peeled off the cotton fibers. A gin can gin 50 pounds a day. Such gin has caused such rare serious and even disastrous consequences. In the United States, even in the south, slavery is on the decline, because slavery is not economically comparable to the combination of free labor and machines. However, the cotton gin made cotton planting a big business, and slavery seemed to be the most suitable for cotton plantations. So slavery was revived, developed and strengthened. The South would rather wage war than give up its "unique system" peacefully. If there were no cotton gin, the American Civil War might not have broken out. When the South Carolina legislature awarded Whitney a $50,000 prize, Whitney returned to New England to make cotton gin. However, the cotton gin is so easy to manufacture and its principle is so easy to understand that Hui Xingni spent all his bonuses and profits to protect his patent right. As a result, he got nothing economically.
Whitney was one of the first members of the American Hall of Fame established by 1900.