M. Arago's Biographical Memoir of James Watt. 241 



rior to The Century of Inventions, and forty-one years before 

 the imprisonment of Worcester. 



Thus, brought to a compai'ison of dates, the controversy 

 seems to be terminated ; for who can maintain that the 

 yeai* 1615 did not precede the year 1663 ' But those whose 

 princijial aim seems to have been to remove every French name 

 from this important chapter in the history of science, suddenly 

 changed their ground as soon as La raison des forces mou- 

 vantes was resuscitated from the dusty shelves in which it had 

 been long entombed. They, without hesitation, broke their 

 former idol ; the Marquis of Worcester was sacrificed to 

 the desire of annihilating the claims of Solomon de Caus, and 

 the bomb placed upon a burning furnace, with its ascending 

 tube, ceased altogether to be the true germ of our present 

 steam-engine ! 



For my own part, I cannot allow that that individual accom- 

 plished nothing that was useful, who, pondering upon the 

 enormous power of steam, raised to a high temperature, was 

 the first to perceive that it might serve to raise great masses 

 of water to all imaginable heights. I cannot admit that no 

 gratitude is due to that engineer who was the first also to de- 

 scribe a machine which was capable of .realizing such efiFects. 

 It ought never to be forgotten, that we can only then cor- 

 rectly judge of an invention, when we transport om-selves 

 in thought to the time when it was proposed, and when 

 we banish from our minds all the knowledge which has been 

 accumulated during the ages posterior to its date. Let us 

 suppose some ancient mechanist, Archimedes, for example, 

 consulted upon the means of elevating water contained in a 

 vast close metallic receiver. He would have suggested great 

 levers, pulleys, simple and compound, the windlass, and pro- 

 bably his ingenious screw ; but what would have been his 

 surprise if, for the solution of the problem, some one had con- 

 tented himself -with a fagot and a match ? Who, then, can 

 refuse the title of an invention, to a contrivance at which the 

 immortal author of the primary and true principles of statics 

 and hydi-ostatics would have been astonished ? This appa- 

 ratus of Solomon de Caus, this close metallic vessel, in which 



