View full lesson: http://ed.ted.com/lessons/how-inventions-change-history-for-better-and-for-worse-kenneth-c-davis Invented in 1793, the cotton gin changed history for good and bad. By allowing one field hand to do the work of 10, it powered a new industry that brought wealth and power to the American South -- but, tragically, it also multiplied and prolonged the use of slave labor. Kenneth C. Davis lauds innovation, while warning us of unintended consequences.