The cotton engine A cotton gin (also known as a "cotton engine") is a machine that swiftly and simply separates cotton fibers from their seeds, allowing for far higher production than traditional cotton separation. Eli Whitney, an American inventor, invented and patented a modern mechanical cotton gin in 1793. The invention proved so effective that it greatly increased the demand for and consumption of cotton fabric during America's early industrial period. Whitney's gin used two screws to turn cotton bolls open, which allowed the oil-rich seeds to be separated from the fiber. This technology eliminated the need for human hand-separation which had been done before his invention. The refined cotton could then be used for fabrics or burned for fuel. Cotton gins played an important role in the expansion of slavery by providing a labor-saving device that allowed slave owners to obtain more cotton per acre and thus increase their profits. Around 1820, improvements were made to the design of the cotton gin by people including James H. Allen and Richard Owen Ellis. These new models were much less complex than Whitney's original gin and they remain in use today in some parts of the world where electricity is not available. In the United States, most cotton was processed using a variation on the Whitney machine. In 1872, John Harvey Kellogg invented the first successful automatic cotton gin.