THE GROWTH OF THE STEAM-ENGINE. 145 



economy in working steam in this manner, it seems gradually dis- 

 placing all other forms of engine. 



"""somwA \ =- 



Fig. 19. Hornblower's Compound Engine, 1781. 



44. An example of this form of pumping-engine, and one which is 

 a favorite with many engineers, is the beam and crank engine (Fig. 



Fig. 20. Compound Pumping-Engine, 1800. 



20), C D,E F, with double cylinder, A, B, working the "combined 

 bucket and plunger," or double-acting pump, J. In its cylinders steam 



VOL. XII. 10 



