Its likely you are thinking of general mechanization of industry during the Song dynasty in the 900s, likely the rise and fall of water-powered power-looms during this period, which wouldn't be recreated until the late 1700s. Ronald A. Edwards of Tamkang University in Taiwan mentions them in his "Textiles of the Tang-Song Dynasty", but I haven't been able to find a more comprehensive source covering them in the past few minutes I've checked