COTTON. The soft vegetable down in the seed vessels of the cotton plant (gossypium herlmesum), cultivated in this country, South America, the East and West Indies, and Egypt. It is an annual plant, which forms its seed in pods, which are triangular, and have each three cells ; in these fie the downy cotton. The fibres of cotton are very fine, delicate, and flexible ; under the microscope they are flat, triangular, and somewhat con torted ; their sides are serrated, which explains the cause of their adhering to gether, and enables them to be spun into thread. In the southern states, three kinds are cultivated : the nankeen cotton, the green seed, and the black seed cotton. The two first are upland and short staple variety. The last has a long fine staple.
Two machines are used to clean the cotton from the seed,—the roller gin and the saw gin. The first consists of two small cylinders, between which the cotton is drawn, while the seed is prevented by its size from passing. The saw gin, in
vented by E. Whitney, is used for the black seed, which adhere too strongly to be separated by the rollers. His appa ratus is a receiver, fitted on one side with wires an eighth of an inch apart; between these pass a number of circular saws, revolving on a common axis. The cotton is caught by the teeth of the saws, and drawn through the grating, which is too narrow to admit the seeds to pass. The cotton thus separated is swept off the saws by a revolving brush ; the seeds fall out at the bottom. The cot ton crop of this country in 1848 was estimated at 1,066,000,000 lbs., value $74,620,000. The following is a tabular view of the value of raw and manufac tured cotton for the last five years, with the amount of export to Britain and France.