ARKANSAS, a river of the United States, which gives its name to the above State, the largest affluent of the Mississippi after the Missouri. It rises in the Rocky Mountains, about lat. 39° N., long. 107° W., flows in a general south-easterly direction through Colorado, Kansas, the Indian Territory, and lastly through the State of Arkansas, and after a course of 2170 miles enters the Mississippi. During greater part of the year it is navigable for steamboats for 800 miles.
ARK´LOW, a town in Ireland, County Wicklow, on the right bank of the Avoca, which falls into the sea about 500 yards below the town; the scene of a severe fight during the rebellion of 1798. Fishing is the chief industry. Pop. 5042.
ARK´WRIGHT, Sir Richard, famous for his inventions in cotton-spinning, was born at Preston, in Lancashire, in 1732, died 1792. The youngest of thirteen children, he was bred to the trade of a barber. When about thirty-five years of age he gave himself up exclusively to the subject of inventions for spinning cotton. The thread spun by Hargreaves' jenny could not be used except as weft, being destitute of the firmness or hardness required in the longitudinal threads or warp. But Arkwright supplied this deficiency by the invention of the _spinning-frame_, which spins a vast number of threads of any degree of fineness and hardness, leaving the operator merely to feed the machine with cotton and to join the threads when they happen to break. His invention introduced the system of spinning by rollers, the carding, or _roving_ as it is technically termed (that is, the soft, loose strip of cotton), passing through one pair of rollers, and being received by a second pair, which is made to revolve with (as the case may be) three, four, or five times the velocity of the first pair. By this contrivance the roving is drawn out into a thread of the desired degree of tenuity and hardness. His inventions being brought into a pretty advanced state, Arkwright removed to Nottingham in 1768 in order to avoid the attacks of the same lawless rabble that had driven Hargreaves out of Lancashire. Here his operations were at first greatly fettered by a want of capital; but two gentlemen of means having entered into partnership with him, the necessary funds were obtained, and Arkwright erected his first mill, which was driven by horses, at Nottingham, and took out a patent for spinning by rollers in 1769. As the mode of working the machinery by horse-power was found too expensive, he built a second factory on a much larger scale at Cromford, in Derbyshire, in 1771, the machinery of which was turned by a water-wheel. Having made several additional discoveries and improvements in the processes of carding, roving, and spinning, he took out a fresh patent for the whole in 1775, and thus completed a series of the most ingenious and complicated machinery. Notwithstanding a series of law-suits in defence of his patent rights, and the destruction of his property by mobs, he amassed a large fortune. He was knighted by George III in 1786.
