SCIENCE AT THE BEGINNING OF THE GENTUHY 



agency, whose limitations not even the enlarged vision 

 of our later century can pretend to outline. 



Of all the contests that were waging in the various 

 fields of science in this iconoclastic epoch, perhaps the 

 fiercest and most turbulent was that which fell within 

 the field of chemistry. Indeed, this was one of the 

 most memorable warfares in the history of polemics. It 

 was a battle veritably Napoleonic in its inception, scope, 

 and incisiveness. As was fitting, it was a contest of 

 France against the world ; but the Napoleonic parallel 

 fails before the end, for in this case France won not 

 only speedily and uncompromisingly, but for all time. 



The main point at issue concerned the central doc- 

 trine of the old chemistry the doctrine of Becher and 

 Stahl, that the only combustible substance in nature is 

 a kind of matter called phlogiston, which enters into 

 the composition of other bodies in varying degree, thus 

 determining their inflammability. This theory seems 

 crude enough now, since we know that phlogiston was a 

 purely fictitious element, yet it served an excellent pur- 

 pose when it was propounded and it held its place as 

 the central doctrine of chemical philosophy for almost a 

 century. 



At the time when this theory was put forward, it 

 must be recalled, the old Aristotelian idea that the four 

 primal elements are earth, air, fire, and water still held 

 sway as the working foundation of all chemical philoso- 

 phies. Air and water were accepted as simple bodies. 

 Only a few acids and alkalies were known, and these 

 but imperfectly ; and the existence of gases as we now 



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