274 LAVOISIER. 



theory ; for it appears that he might just as well have 

 called oxygen the alkalizing principle as the acidifying, 

 or rather much better, since , all the alkalis save one 

 contain it and the alkaline earths to boot. But he also 

 should have recollected that no acid of them all contains 

 so much oxygen as water, and yet nothing Ijgss like an 

 acid can well be imagined. We now have still further 

 instances of the same kind against this theory, and which 

 might justify us in calling hydrogen the acidifying prin- 

 ciple as well as oxygen. Upwards of two hundred acids 

 contain hydrogen either with or without oxygen present. 

 Hence he might really have reckoned hydrogen the acidi- 

 fying principle upon fully better grounds than support his 

 choice of oxygen; and the truth appears to be, that 

 ..there is no one substance which deserves the name. 



It is, then, quite clear that M. Lavoisier committed a 

 great error in his induction, and that he framed a theory 

 which was in the extent to which he pressed it wholly 

 without foundation not merely without sufficient proof 

 from the facts, but contrary to the facts. Newton gives 

 it as a fundamental rule of philosophising, that we are 

 to state the inferences from phenomena with the excep- 

 tions which occur, and if a first induction should be 

 made from imperfect views of the phenomena, then to 

 correct it by the exceptions afterwards found to exist. 

 But from this rule Lavoisier has departed entirely: 

 because, though subsequent experiments have greatly 

 increased the number of the exceptions, yet there were 

 many striking ones at the time he formed his system, 

 and these were left out of view in its formation. 



After all the deductions, however, which can fairly be 

 made from his merits, these stand high indeed, and leave 



