244 The Rise of the Modern [lect. 



was it is true a philosopher, a real investigator of nature, but 

 he was also, and even more so. a politician and a theologian. 

 In this latter side of his life the mode of thinking which he 

 naturally adopted led him to regard every new fact which came 

 before him as confirming the views at which he had already 

 arrived, and perhaps especially encouraged him to expound the 

 new fact as affording such welcome confirmation. Possibly it 

 was this other side of his mental activity which led him to cling 

 so closely to the phlogiston faith. Indeed when we compare 

 his character with that of Stahl, the founder of the phlogiston 

 theory, we may see a certain likeness between the two. 



The man who if he was not the first to prepare, was at least 

 the first to discover oxygen, was free from all such tendencies 

 to cling to old opinions. He was wholly and entirely the man 

 of science holding to an old view only until the new one is 

 ready, always prepared, at the bidding of a new indubitable 

 fact, to throw aside at once his most cherished ideas. 



I need not dwell long on the personal history, the private 

 life of Antoine Laurent Lavoisier, and indeed there is little to 

 tell save the tragic end of it. 



Born on Aug. 26, 1743, he was educated at the College 

 Mazarin. Here, though intended for the law, he was early 

 drawn into studies of natural science ; and to these he quietly 

 devoted the rest of his life, spending his days, save those 

 which he had to give up to official duties in connection with 

 Le Ferme General which he early took upon himself, in the 

 researches of which I am about to speak, and in others which 

 lie outside my present task. In 1768, at the early age of 

 twenty-five, he was admitted into the Academy of Sciences, 

 to which body he from time to time made known the brilliant 

 results of his labours. 



In 1775, the year after Priestley had prepared his dephlogis- 

 ticated air, Lavoisier published the immortal paper " On the 

 " nature of the principle which combines with metals during 

 " their calcination." He saw the facts which Priestley had seen, 

 but saw them eye to eye, saw them without the veil of precon- 

 ceived ideas. The metallic oxide when it became a metal did not 

 take up phlogiston from the air, but gave up something to the 



