W mi 



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 out 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. — Metbods 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.— 27 



