WATT. 357 



improvements on the apparatus ; and though he did not 

 use the vacuum as Papin had done, but only as it is 

 used in the sucking-pump, he yet produced it by apply- 

 ing cold water to the outside of the cylinder. The 

 machines made by him were so manageable that they 

 were brought into use for raising water in many 

 country houses. D'Alesme exhibited a machine before 

 1705 (as appears by the ' Histoire de 1' Academic des 

 Sciences' for that year, p. 1 37), in which water was made 

 to spout to a great height by the force of steam alone. 

 It is extremely doubtful if Papin ever erected any 

 steam engine, either upon his own or upon any other 

 principle. It is certain that he did not adhere to the 

 two great propositions which he had brought forward, 

 the operating by a piston, and the operating by the 

 pressure of the atmosphere ; he recurred to the old 

 plan of making the steam act directly upon the weight 

 to be raised. In 1711 Newcomen, an iron-master of 

 Dartmouth, and Galley, or Cawley, a glazier of the 

 same town, constructed an engine upon Papin's principle 

 of a piston and a condensing process, using, however, 

 Savery's mode of creating a vacuum by cold affusion, 

 for which they were led by an accident to substitute 

 the method of throwing a jet or stream of cold water 

 into the cylinder. This important improvement saved, 

 in a considerable degree, the waste of heat occasioned 

 by Savery's method of condensing. Their engine 

 could be applied with advantage to raise water from 

 mines, which Savery's was wholly incapable of effect- 

 ing, its power being limited to that of the sucking- 

 pump. Newcomen's engine, as it is generally called, 

 made no use at all of the direct force of steam ; it 



