THE CONQUEST OF NATURE 



The practical steam engine in its modern form dates, 

 as just mentioned, from the latter part of the eighteenth 

 century, and was perfected by James Watt, who is com- 

 monly thought of as being its inventor. In point of fact, 

 however, the history of most inventions is duplicated 

 here, as on examination it appears that various fore- 

 runners of Watt had been on the track of the steam 

 engine, and some of them, indeed, had produced a 

 workable machine of no small degree of efficiency. 



The very earliest experiments were made away back 

 in the Alexandrian days in the second century before 

 the Christian era, the experimenter being the famous 

 Hero, whose work in an allied field was referred to in 

 the preceding chapter. Hero produced or at least 

 described and so is credited with producing, though 

 the actual inventor may have been Ctesibius a little 

 toy mechanism, in which a hollow ball was made to 

 revolve on an axis through the agency of steam, which 

 escaped from two bent tubes placed on opposite sides 

 of the ball, their orifices pointing in opposite directions. 

 The apparatus had no practical utility, but it sufficed 

 to establish the principle that heat, acting through the 

 agency of steam, could be made to do mechanical work. 

 Had not the age of Hero been a time of mental stasis, 

 it is highly probable that the principle he had thus 

 demonstrated would have been applied to some more 

 practical mechanism in succeeding generations. As it 

 was, however, nothing practical came of his experi- 

 ment, and the steam turbine engine was remembered 

 only as a scientific toy. 



No other worker continued the experiments, so far 



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