In the very year, however, in which John Hargreaves, the poor weaver, migrated to Nottingham, Richard Arkwright, a poor barber's assistant, took out a patent for his still more celebrated machine for spinning by rollers. In one respect Arkwright was much worse off than Hargreaves: the latter had a helpmate meet for him, the former had a wife who is said to have destroyed the models her husband had made and to have opposed him in every step of his career. But Arkwright was not deterred from his life pursuit by the poverty of his circumstances or the scandalous conduct of his wife. After many years of intense and opposed devotion to the possible application of a simple principle he had conceived in his mind, namely, that of spinning by means of rollers revolving at varying rates of rapidity, he succeeded in contriving and patenting his memorable machine, which, more than any other one invention, localized and concentrated in England the gigantic cotton-industry of the world. Arkwright's idea and achievement was to pass the coarse thread drawn out from the rovings over two pairs of rollers in succession, the first of which revolving slowly fined the thread down evenly and gradually, and then this thread was passed over a second pair of rollers turning with a high velocity and drawing out the line into any requisite tenuity. Thus a cotton thread was spun capable of being used as warp. Cotton cloth as such could now be manufactured in England. From the circumstance that the mill, at which Arkwright's machinery was first erected, was driven by water power, the machine received the inappropriate name of the "water-frame"; and the thread spun on these rollers was commonly called the "water-twist." The old mode of carding the cotton by hand now furnished the "rovings" too slowly to meet the wants of the new spinning-jenny and the new water-frame; and these great inventions would consequently have proven comparatively useless, had not a more efficient and rapid process of carding the cotton superseded just at the right time the old system of hand-carding. Lewis Paul introduced revolving cylinders for carding the raw cotton into rovings preparatory to spinning, in partial imitation perhaps of Arkwright's principle of spinning the rovings by the rotatory motion of rollers. Paul's machine consisted "_of a horizontal cylinder, covered in its whole circumference with parallel rows of cards with intervening spaces, and turned by a handle. Under the cylinder was a concave frame, lined internally with cards exactly fitting the lower half of the cylinder, so that when the handle was turned, the cards of the cylinder and of the concave frame worked against each other and carded the wool. The cardings were of course only of the length of the cylinder, but an ingenious apparatus was attached for making them into a perpetual carding. Each length was placed on a flat broad riband, which was extended between two short cylinders, and which wound upon