23 MULTI-SPEED HUBS, GEAR SHIFT AND POWER TRANSMISSION MECHANISMS, COMBUSTION, [ STEAM, WIND, AND HYDRAULIC ] MOTORS [ ,AND HYDRAULIC PUMPS ] , R.P.M. REGULATORS FOR MOTORS, [ BELT PULLEYS, ] CLUTCHES OF ALL KINDS; AGRICULTURAL, DOMESTIC AND INDUSTRIAL MACHINES AND DEVICES-NAMELY, MOTORIZED LAWN-MOWERS FOR USE BY GARDENERS [ , AND MOTORIZED BUILDING HOISTS AND ELEVATORS ] ; ALSO BICYCLE CHAINS, SPROCKETS AND GEARS, AND COMPONENT PARTS OF THE ABOVE MENTIONED ARTICLES