Figures. — Watt engine of 1782 (British Patent 1321, March 12, 

 1782) showing the rack and sector used to guide the upper end 

 of the piston rod and to transmit force from piston to working 

 beam. This engine, with a 30-inch cylinder and an 8-foot 

 stroke, was arranged for pumping. Pump rod SS is hung from 

 sector of the working beam. From James P. Muirhead, The 

 Origin and Progress of the Mechanical Inventions of James Watt 

 (London, 1854, vol. 3, pi. 15). 



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BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



