2 8 HER OES OF INVENTION AND DISCO VER Y. 



with the contrivance proposed by De Caus and the Marquis of 



Worcester for the appUcation of the expansive force of steam ; 



and, wherever the machine can be economically employed, the 



former part of it is that which operates with by far the most effect 



Not long after Savery had invented his engine, Thomas 



Newcomen, an ironmonger, and John Galley, a glazier, both of 



Dartmouth, in Devonshire, began also to direct their attention 



to the employment of steam as a mechanic power. Theii 



first engine was constructed about the year 1711. This 



contrivance, which is commonly known by the name of New- 



comen's engine, proceeded mainly upon the principle formerly 



adopted by Papin, but subsequently abandoned both by him 



and those who immediately followed him in the cultivation of 



this department of mechanics, of making the moving power of 



the machinery the weight of the atmosphere acting upon a 



piston, so as to carry it down through a vacuum created by the 



condensation of the steam. Newcomen's apparatus is, on this 



account, often distinguished by the name of the Atmospheric 



engine. Its inventors, however, instead of adopting Papin's 



clumsy method of cooling his steam by the removal of the fire, 



employed, in the first instance, the expedient of pouring cold 



water on the containing vessel, as Savery had done before them, 



though without being aware, it is said, of his prior claim to the 



improvement. They afterwards exchanged this for the still 



better method, already described as introduced by Desaguliers 



into Savery's engine, of injecting a stream of water into the 



cylinder, which is said to have been suggested to them by the 



accident of some water having found admission to the steam 



through a hole which happened to have worn itself in the 



piston. This engine of Newcomen, which in the course of a 



very few years after its invention was brought to as high a state 



