A one-page patent abstract from the journal Engineering (7 December 1900) describing R. Taylor's patent no. 22,771 of Oldham for self-acting mules. The invention uses flanged gears with a cut-away portion, or gears with an extra large tooth and matching recess, so the drawing-out scroll and check scroll can only be refitted in their correct relative positions. This prevents excessive strain and breakage of the ropes connecting the scrolls to the carriage. Two figures show the scroll wheels and a sectional elevation of the shafts and gearing.