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CHAPTER VI. 

 EPOCH OF THE THEORY OF OXYGEN. LAVOISIER. 



Sect. 1. Prelude to the Theory. Its Publication. 



WE arrive now at a great epoch in the history 

 of Chemistry. Few revolutions in science 

 have immediately excited so much general notice 

 as the introduction of the theory of oxygen. The 

 simplicity and symmetry of the modes of combina- 

 tion which it assumed; and, above all, the con- 

 struction and universal adoption of a nomenclature 

 which applied to all substances, and which seemed 

 to reveal their inmost constitution by their name, 

 naturally gave it an almost irresistible sway over 

 men's minds. We must, however, dispassionately 

 trace the course of its introduction. 



Antoine Laurent Lavoisier, an accomplished 

 French chemist, had pursued, with zeal and skill, 

 researches such as those of Black, Cavendish, and 

 Priestley, which we have described above. In 1774, 

 he showed that, in the calcinations of metals in 

 air, the metal acquires as much weight as the air 

 loses. It might appear that this discovery at once 

 overturned the view which supposed the metal to 

 be phlogiston added to the calx. Lavoisier's con- 

 temporaries were, however, far from allowing this ; 

 a greater mass of argument was needed to bring 



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