WHITNEY, Eli, inventor, born in Westborough, Massachusetts, 8 December, 1765; died in New Haven, Connecticut, 8 January, 1825. During the Revolutionary war he was engaged in making nails by hand. Subsequently, by his industry as an artisan and by teaching, he was able to defray his expenses at Yale, where he was graduated in 1792. In the same year he went to Georgia under an engagement as a private tutor, but, on arriving there, found that the place had been filled. He then accepted the invitation of the widow of General Nathanael Greene to make her place at Mulberry Grove, on Savannah river, his home while he stud-led law. Several articles that he had devised for Mrs. Greene's convenience gave her great faith in his inventive powers, and when some of her visitors regretted that there could be no profit in the cultivation of the green seed-cotton, which was considered the best variety, owing to the great difficulty of separating it from the seed, she advised them to apply to Whitney "who," she said, "could make anything." A pound of green seed-cotton was all that a negro woman could at that period clean in a day. Mr. Whitney up to that time had seen neither the raw cotton nor the cotton seed, but he at once procured some cotton from which the seeds had not been removed, although with trouble, as it was not the season of the year for the cultivation of the plant, and began to work out his idea of the cotton-gin. He was occupied for some months in constructing his machine, during which he met with great difficulty, being compelled to draw the necessary iron-wire himself, as he could obtain none in Savannah, and to manufacture his own iron tools. Near the end of 1792 he succeeded in making a gin of which the principle and mechanism are both exceedingly simple. Its main features are a cylinder four feet long and five inches in diameter, upon which is set a series of circular saws half an inch apart and projecting two inches above the surface of the revolving cylinder. A mass of cotton in the seed, separated from the cylinder by a steel grating, is brought into contact with the numerous teeth on the cylinder. These teeth catch the cotton while playing between the bars, which allow the lint, but not the seed, to pass. Beneath the saws is a set of stiff brushes on another cylinder revolving in the opposite direction, which brush off from the saw-teeth the lint that these have just pulled from the seed. There is also a revolving fan for producing a current of air to throw the light and downy lint that is thus liberated to a convenient distance from the revolving saws and brushes. Such are the essential principles of the cotton-gin as invented by Whitney and as it is still used; but in various details and workmanship it has been the subject of many improvements, the object of which has been to pick the cotton more perfectly from the seed, to prevent the teeth from cutting the staple, and to give greater regularity to the operation of the machine. By its use the planter was able to clean for market, by the labor of one man, one thousand pounds of cotton in place of five or six by hand. Mrs. Greene and Phineas Miller were the only persons that were permitted to see the machine, but rumors of it had gone through the state, and before it was quite finished the building in which it was placed was broken into at night and the machine was carried off. Before he could complete Iris model and obtain a patent, a number of machines based on his invention had been made surreptitiously and were in operation. In May, 1793, he formed a partnership with Mr. Miller, who had some property, and went to Connecticut to manufacture the machines; but he became involved in continual trouble by the infringement of his patent. In Georgia it. was boldly asserted that he was not the inventor, but that something like it had been produced in Switzerland, and it was claimed that the substitution of teeth cut in an iron plate for wire prevented an infringement on his invention. He had sixty lawsuits pending before he secured a verdict in his favor. In South Carolina the legislature granted him $50,000, which was finally paid after vexatious delays and lawsuits. North Carolina allowed him a percentage for the use of each saw for five years, and collected and paid it over to the patentees in good faith, and Tennessee promised to do the same thing, but afterward rescinded her contract. For years--amid accumulated misfortunes, lawsuits wrongfully decided against him, the destruction of his manufactory by fire, the industrious circulation of the report that," his machine injured the fibre of the cotton, the refusal of congress, on account of the opposition of southern members, to allow the patent to be renewed, and the death of his partner--Mr. Whitney struggled on until he was convinced that he should never receive a just compensation for his invention. In 1791 the amount of cotton that was exported amounted to only 189,500 pounds, while in 1803, owing to the use of his gin, it had risen to more than 41,000,000 pounds. Despairing of gaining a competence, he turned his attention in 1798 to the manufacture of fire-arms near New Haven, from which he eventually gained a fortune. He was the first manufacturer of fire-arms to effect the division of labor to the extent of making it the duty of each workman to perform by machinery but one or two operations on a single part of the gun, and thus made interchangeable the parts of the thousands of arms in process of manufacture at the same time. His first contract was with the United States government for 10,000 stand of muskets to be finished in about two years. For the execution of this order he took two years for preparation and eight more for completion, lie gave bonds for $30,000, and was to receive $13.40 for each musket, or 8134,000 in all. Immediately he began to build an armory at the foot of East Rock, two miles from New Haven, in the present village of Whitneyville, where, through the successive administrations from that of John Adams, repeated contracts for the supply of arms were made and fulfilled to the entire approbation of the government. The construction of his armory, and even of the commonest tools, which were devised by him for the prosecution of the business in a manner peculiar to himself, evinced the fertility of his genius and the precision of his mind. The buildings became the model upon which the national armories were afterward arranged, and many of his improvements were transferred to other establishments and have become common property. His advance in the manufacture of arms laid this country under permanent obligations by augmenting the means of national defence. Several of his inventions have been applied to other manufactures of iron and steel and added to his reputation, he established, a fund of 8500 at Yale, the interest of which is expended in the purchase of books on mechanical and physical science. In 1817 he married a daughter of Judge Pierpont Edwards. Robert Fulton said that "Arkwright, Watt, and Whitney were the three men that did most for mankind of any of their contemporaries," and Macaulay said" "What Peter the Great did to make Russia dominant, Eli Whitney's invention of the cotton-gin has more than equalled in its relation to the power and progress of the United States." See " Memoir of Eli Whitney," by Denison Olmsted (New Haven. 1846).