352 TEE POPULAR SCIENCE MONTHLY, 



with glib readiness. But those who have looked at the history of 

 the steam-engine know, of course, that there were steam-engines 

 in abundance long before Watt's, and that Watt himself worked 

 deliberately on the basis of Newcomen's model, Newcomen, in 

 turn, had improved on Papin's invention, and Papin perhaps on 

 De Caux's, and finally on Hero's. Now, nobody denies that Watt 

 was a very great engineer ; if he had never invented the double- 

 acting engine at all, indeed, he would have been remembered 

 among the mechanical geniuses of the world by his numerous 

 other improvements and discoveries ; but he was not so absolutely 

 supreme and unique as the popular fancy bas made him out to 

 be. Indeed, taking into consideration the date of its construction, 

 Newcomen's engine was a much more remarkable triumph of hu- 

 man ingenuity that James Watt's. But Watt introduced the final 

 details which rendered steam a power in the world, and with him 

 accordingly rest the popular suffrages as "the inventor of the 

 steam-engine." Similarly, who invented the locomotive ? George 

 Stephenson, says everybody, as before. But those who have looked 

 at the history of the locomotive know, of course, that both loco- 

 motives and railways existed in plenty before Stephenson's, and 

 that the Rocket was merely the most successful competitor among 

 many contemporary competitors for public favor. Nobody denies 

 George Stephenson's marvelous native engineering abilities; on 

 the whole, taking into consideration his humble beginnings, he 

 seems to me more of a heaven-born genius in his own way than 

 almost anybody else with whose history I am acquainted. But 

 the work he did upon the locomotive was adaptive and develoj)- 

 mental, not original and novel. The great invention did not 

 spring in full panoply — like Athene from the head of Zeus — out 

 of any one engineer's profound brain ; it grew slowly, piece by 

 piece, like everything else, from a hundred men's co-operating in- 

 telligences. 



Like everything else, I say deliberately, for it is the same with 

 every great invention. Look at the telegraph, so hotly debated 

 between Morse and Wheatstone ; look at the telephone, equally 

 divided between Edison and Bell ; look at photography, whose 

 several stages owed so much successively to Wedgwood and Davy, 

 to Niepce and Daguerre, to Talbot and to Archer. " Great discov- 

 eries," says Prof. Fiske, with evident wisdom, " must always be con- 

 cerned with some problem of the time which many of the world's 

 foremost minds are just then cudgeling their active brains about." 

 It was so with the discovery of the differential calculus and of the 

 planet Neptune ; with the interpretation of the Egyptian hiero- 

 glyphics and of the cuneiform inscriptions ; with the undulatory 

 theory of light and the mechanical equivalent of heat ; with the 

 nebular hypothesis and with spectrum analysis. In some cases 



