THE STEAM-ENGINE. 



(SECOND LECTURE.) 



Mechanical Force of Steam. Facts to be remembered. Watt finds Condensation in the Cylinder 

 incompatible with a due Economy of Fuel. Conceives the notion of Condensing oat of the Cyl- 

 inder. Discovers separate Condensation. Invents the Air-Pump. Substitutes Steam Pressure 

 for Atmospheric Pressure. Invents the Steam Case or Jacket. His first Experiments to realize 

 these Inventions. His Experimental Apparatus. His Models at Delft House. Difficulties of 

 bringing the improved Engines into Use. Watt employed by Roebuck. His Partnership. His 

 first Patent. His Single- Acting Engine. Discovery of the Expansive Action of Steam. Its 

 Mechanical Effects. Its Variable Action. Methods of Equalizing it. Its extensive Application 

 in the Cornish Engines. Extension of the Steam-Engine to Manufactures. Attempts of Papiu, 

 Savery, Hull, Champion, Stewart, and Washborough. Watt's second Patent. Sun-and-Planet 

 Wheels. Valves' of Double- Acting Engine. 



VOL. II.-37 



