GAY-LUSSAC 177 



Chimie, tome xxii., p. 415, he gave the chemical process 

 in the formation of specular iron. 



In 1809, the same year that he discovered the law of 

 volumes, Gay-Lussac was elected Professor of Chemistry 

 at his alma mater the Ecole Polytechnique, Paris and 

 remained at the great military school for twenty-three 

 years. In 1832 he transferred to the same chair in the 

 Jardin des Plantes. 



In 1823 he published a memoir on the dynamics of 

 earthquakes, in which he says that " the earth, so many 

 centuries old, still preserves an internal force, which raises 

 mountains, overturns cities, and agitates the entire mass. 

 Most mountains, in issuing from the bosom of the earth, 

 must have left vast cavities, which have remained empty, 

 at least unless they have been filled with water and gases." 



The existence of alkaline metals was prophesied by 

 Lavoisier in 1793 ; and potassium and sodium were dis- 

 covered by Davy in 1807, by means of the voltaic pile; 

 and in the following year Gay-Lussac discovered a new 

 process which yielded both potassium and sodium more 

 abundantly than the voltaic pile. This was by the action 

 of white-hot iron on the hydroxides of potassium and 

 sodium. No doubt the brilliant researches of Davy 

 stimulated Gay-Lussac and his collaborates Thnard, 

 and in their Recherches Physico-Chimiques (1811) are 

 to be found many remarkable observations on the action 



of the voltaic pile which Napoleon had constructed for 



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