386 JAJIES WATT. 



them by means of movable pistons, was still in its in- 

 fancy. Wherefore in Newcomen's early engines, the 

 piston was covered with water intended to fill up the 

 vacancies between the circumference of this movable 

 piece and the surface of the cylinder. To the great sur- 

 prise of the manufacturers, one of their engines began 

 one day to oscillate much faster than usual. After many 

 examinations it was ascertained that on that day the pis- 

 ton was pierced, that some cold water fell into the cylinder 

 by little drops, and that by passing through the steam, 

 they annihilated it rapidly. From this fortuitous inci- 

 dent may be dated the entire abandonment of all exterior 

 refrigeration, and the adoption of a watering pot, to shed 

 a shotver of cold water throughout the capacity of the 

 cylinder at the instant of the piston's descent. The 

 alternate up and down motion now acquired all the de- 

 sired swiftness. 



But let us see whether there was not another equally 

 important improvement effected also by chance. 



Newcomen's first engine required the most uninter- 

 rupted attention from the pei'son who had to open and 

 shut the cocks either to introduce the steam into the 

 cylinder, or to throw in the cold shower intended to con- 

 dense it. It happened on a certain day that this person 

 was young Henry Potter.* The companions of this 

 child were then at play, and their exclamations of joy 

 tantalize him severely. He longs to go and join them ; 

 but the task entrusted to him would not allow of half a 

 minute's absence. His mind becomes excited ; strong 

 passion awakes his genius : he discovers relative con- 

 nections of which he had never dreamt before. Of the 



* The name of this play-loving and ingenious boy appears to have 

 been Humjjhrey Potter. — Translator. 



