CH. XXVII. RAPID ADVANCE OF CHEMISTRY. 239 



something into the atmosphere but take a gas out of it. Dr. 

 Black was one of the first to be convinced, but Priestley- 

 died without giving up his old opinions. The younger 

 chemists, however, saw the truth of Lavoisier's explanation, 

 and from this time chemistry advanced very rapidly. 

 Lavoisier invented an entirely new set of terms instead of 

 the old names of the alchemists, and though his terms have 

 been greatly altered by later discoveries, still many of them 

 will always be used. He repeated with a better apparatus 

 Cavendish's experiment of turning hydrogen and oxygen 

 into water, and he gave hydrogen its name from vliop^ water, 

 and ytvvaw, I produce. Lastly, he published his * Elements 

 of Chemistry,' in which he gave a clear explanation of the 

 different chemical changes, and how students could work 

 them out for themselves. 



Lavoisier was now at the height of his fame, full of his 

 new theory, and prepared to devote the rest of his life to 

 making chemistry a grand science ; but a very sad fate was 

 awaiting him. In 1793 the great French Revolution broke 

 out in Paris. Lavoisier was a farmer-general, that is a kind 

 of collector of taxes, and all the farmers-general were hated 

 by the people ; so he knew that he should most likely lose 

 all his fortune, and was prepared to work for his living ; but 

 he had not expected the blow which fell upon him. All the 

 farmers-general were condemned to death, and though a 

 physician named Halle, who deserves always to be remem- 

 bered for this act, pleaded that Lavoisier's life should be 

 spared till he had completed his experiments, the ignorant 

 and brutal Government replied, ' We do not need learned 

 men,' and on May 18, 1794, at the age of fifty-one, Lavoisier 

 was guillotined. 



After his death the French School of Chemistry took the 



