An encyclopedia article on the machinery that turns raw cotton into warp and weft yarn in 19th-century mills, with emphasis on American builders. It covers openers, eveners and lappers, carding engines and card-clothing manufacture, drawing frames, roving frames (speeders and fly frames), ring spinning frames and spindles, self-acting mules, spoolers, warpers and slashers (dressing). Each machine is explained with lettered engravings (Figs. 859-893), operating principles, and output and horse-power figures.