THE STORY OF NINETEENTH-CENTURY SCIENCE 



pendently of Priestley and Scheele. At all events, he at 

 once began experimenting with it, and very soon it 

 dawned upon him that this remarkable substance might 

 furnish a key to the explanation of many of the puzzles 

 of chemistry. He found that oxygen is consumed or 

 transformed during the combustion of any substance in 

 air. He- reviewed the phenomena of combustion in the 

 light of this new knowledge. It seemed to him that 

 the new element explained them all without aid of the 

 supposititious element phlogiston. What proof, then, 

 have we that phlogiston exists ? Very soon he is able 

 to answer that there is no proof, no reason to believe 

 that it exists. Then why not denounce phlogiston as a 

 myth, and discard it from the realm of chemistry ? 



Precisely this is what Lavoisier purposes to do. He 

 associates with him three other famous French chemists, 

 Berthollet, Guy ton de Morveau, and Fourcroy, and sets 

 to work to develop a complete system of chemistry based 

 on the new conception. In 1788 the work is completed 

 and given to the world. It is not merely an epoch-mak- 

 ing book; it is revolutionar} 7 . It discards phlogiston 

 altogether, alleging that the elements really concerned 

 in combustion are oxygen and heat. It claims that 

 acids are compounds of oxygen with a base, instead of 

 mixtures of " earth " and water ; that metals are simple 

 elements, not compounds of " earth " and " phlogiston " ; 

 and that water itself, like air, is a compound of oxygen 

 with another element. 



In applying these ideas the new system proposes an 

 altogether new nomenclature for chemical substances. 

 Hitherto the terminology of the science has been a mat- 

 ter of whim and caprice. Such names as " liver of sul- 

 phur," " mercury of life," " horned moon," " the double 



32 . 



