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, 
resulting from a somewhat lengthened survey of the field of 
science, from a particular standpoint, which I will now proceed 
to explain. 
3. 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 phlogiston , 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 Not only has it not been 
replaced by any other, but we cannot even conceive the possi- 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. f 
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., Eevwe Scientifique, 16 Mars, 1872. 
t Wurtz’s History of Chemical Theory , p. 12. 
