CAPTIVE MOLECULES 



to speak of it as the germ merely; the thing itself was 

 there, requiring only the elaboration of details to bring 

 it to perfection. 



Watt immediately set to work to put his brilliant 

 conception of the separate condenser to the test of 

 experiment. He connected the cylinder of a Newcomen 

 engine with a receptacle into which the steam could be 

 discharged after doing its work on the piston. The 

 receptacle was kept constantly cooled by a jet of water, 

 this water and the water of condensation, together with 

 any air or uncondensed steam that might remain in the 

 receptacle, being constantly removed with the aid of an 

 air pump. The apparatus at once demonstrated its 

 practical efficiency, and the modern steam engine had 

 come into existence. 



It was in the year 1765, when Watt was twenty-nine 

 years old, that he made his first revolutionary experi- 

 ment, but his first patents were not taken out until 

 1769, by which time his engine had attained a relatively 

 high degree of perfection. In furthering his idea of 

 keeping the cylinder at an even temperature, he had 

 provided a covering for it, which might consist of wood 

 or other poorly conducting material, or a so-called 

 jacket of steam that is to say, a portion of steam ad- 

 mitted into the closed chamber surrounding the cylinder. 

 Moreover, the cylinder had been closed at the top, and 

 a portion of steam admitted above the piston, to take 

 the place of the atmosphere in producing the down 

 stroke. This steam above the piston, it should be ex- 

 plained, did not connect with the condensing receptacle, 

 so the engine was still single-acting; that is to say it 



VOL. vn. 7 [ 97 ] 



