Eli Whitney's cotton gin mechanically separated cotton fibers from seeds. It processed raw cotton rather than turning cotton directly into cloth.
More efficient ginning helped expand cotton production in the American South. That expansion was also tied to the plantation economy and increased demand for enslaved labor.
Eli Whitney's patent
Eli Whitney (1765–1825) applied for a patent of his cotton gin on October 28, 1793; the patent was granted on March 14, 1794, but was not validated until 1807. Whitney's patent was assigned patent number 72X. There is slight controversy over whether the idea of the modern cotton gin and its constituent elements are correctly attributed to Eli Whitney. The pamphlet "Woman as Inventor," published in 1883, claimed Catharine Littlefield Greene suggested to Whitney the use of a brush-like component instrumental in separating out the seeds and cotton.
Whitney's cotton gin model was capable of cleaning 50 pounds (23 kg) of lint per day. The model consisted of a wooden cylinder covered by rows of slender wires which caught the fibers of the cotton bolls. Each row of wires then passed through the bars of a comb-like grid, pulling the cotton fibers through the grid as they did. The comb-like teeth of the grids were closely spaced, preventing the seeds, fragments of the hard dried calyx of the original cotton flower, or sticks and other debris attached to the fibers from passing through. A series of brushes on a second rotating cylinder then brushed the now-cleaned fibers loose from the wires, preventing the mechanism from jamming.
Many contemporary inventors attempted to develop a design that would process short staple cotton, and Hodgen Holmes, Robert Watkins, William Longstreet, and John Murray had all been issued patents for improvements to the cotton gin by 1796. Patent courts eventually decided, after years of legal battles, to nullify Hodges Holmes's patent for the saw gin and to declare Whitney the inventor. Although he spent many years in court attempting to enforce his patent against planters who made unauthorized copies, a change in patent law ultimately made his claim legally enforceable – too late for him to make much money from the device in the single year remaining before the patent expired.
Early cotton gins
The earliest versions of the cotton gin consisted of a single roller made of iron or wood and a flat piece of stone or wood. The earliest evidence of the cotton gin is found in the fifth century, in the form of Buddhist paintings depicting a single-roller gin in the Ajanta Caves in western India. These early gins were difficult to use and required a great deal of skill. A narrow single roller was necessary to expel the seeds from the cotton without crushing the seeds. The design was similar to that of a mealing stone, which was used to grind grain. The early history of the cotton gin is ambiguous, because archeologists likely mistook the cotton gin's parts for other tools.
Effects in the United States
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 gin, cotton became a tremendously profitable business, creating many fortunes in the Antebellum South. Cities such as New Orleans, Louisiana; Mobile, Alabama; Charleston, South Carolina; and Galveston, Texas, became major shipping ports, deriving 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 region became even more dependent on plantations that used black slave labor, with plantation agriculture becoming the largest sector of its economy. While it took a single laborer about ten hours to separate a single pound of fiber from the seeds, a team of two or three slaves using a cotton gin could produce around fifty pounds of cotton in just one day. 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.