A two-page dictionary entry on the spinning mule from Knight's American Mechanical Dictionary. It defines the machine, recounts Samuel Crompton's invention and its later improvement by Roberts into the self-acting mule, and explains how the drawing rollers, spindle carriage, stretch and winding work. It also compares mule spinning with throstle spinning and includes an engraving (Fig. 3254) of a non-self-acting mule with parts labeled.