to help forward, as much as in him lies, the good work, and 

 to distinguish between the false and the true. 



2. With this intention, I present the following observations, 

 I'esulting from a somewhat lengthened survey of the field of 

 science, from a particular standpoint, which I will now proceed 

 to explain. 



8. Exactly one hundred years ago, from the date of com- 

 mencing this paper (1872), the celebrated Lavoisier deposited 

 at the French Academy a sealed packet, which may be said to 

 have contained the germ of the modern science of chemistry. 

 Before this era there had been an abundance of theories — 

 dreams and speculations as to the relations of created substance ; 

 one of which, that of pidogistoii, was so beautiful and so at- 

 tractive, that it enlisted in its service, with a kind of fanatical 

 devotion, even men such as Priestley and others, who with their 

 own hands were accumulating facts tending to its destruction. 

 Nevertheless, the element of truth was wanting. It was false 

 science, and Lavoisier came down upon it with the irresistible 

 logic of the balance and weights, and the theory is now 

 no longer known except as matter of history. For this 

 triumph of common sense applied to science he had the honour 

 of being burnt in effigy at Berlin.^ Truth made its way 

 nevertheless, and this great chemist had the satisfaction of 

 seeing his theory generally accepted before the revolutionary 

 fury of France cut him off in the flower of his age. If any- 

 thing could vie in importance with the discoveries he made, it 

 would be his method, which consists in applying the balance to 

 all chemical phenomena, and which is specially his own because 

 he was its true promoter. Cavendish, Bergmann, Margraf, had 

 made quantitative analyses, but neither of them had thought of 

 applying the study of ponderal relations to the solution of a 

 theoretical question. This idea and the merit of it are due to 

 Lavoisier. The method which he inaugurated is the only true 

 method of chemical research. Not only has it not been 

 replaced by any other, but we cannot even conceive the possi- 

 bility of such replacement. t 



4. Lavoisier assumed that in chemical reaction nothing is 

 lost, nothing is created, matter being indestructible. This must 

 be remembered, as we shall have to revert to the subject. He 

 recognized as simple bodies those which, when submitted to the 

 action of all available forces, remain constantly the same, 

 indestructible, undecomposable. He recast the ancient notions 

 on the nature of the elements, and put an end to the hope of 



* M. F. Papillon, article " Lavoisier," &c.,J2el•we^S^c^e?^#^/lg'tt<3, 16 Mars, 1872. 

 t Wurtz's History of Chemical Theory, p. 12. 



