NEW CONCEPTIONS IN SCIENCE 



Hero's engine was a sort of steam-turbine, ran 

 without piston or cylinder, was simple in design, 

 easy to build; a child could understand its opera- 



HERO S STEAM-TURBINE 



The steam was carried up from the closed caldron, p, through the tube, o, 

 into the ball, y, and escaping from the nozzles, w and s, caused the ball to 

 revolve. 



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