THE STORY OF NINETEENTH-CENTURY SCIENCE 



specific heat of atoms, and of isomorphism, took their 

 place as new levers of chemical science. With the aid 

 of these new tools an impregnable breastwork of facts 

 was soon piled about the atomic theory. And John 

 Dalton, the author of that theory, plain, provincial 

 Quaker, working on to the end in semi-retirement, be- 

 came known to all the world and for all time as a mas- 

 ter of masters. 



in 



During those early years of our century, when Dalton 

 was grinding away at chemical fact and theory in his 

 obscure Manchester laboratory, another Englishman held 

 the attention of the chemical world with a series of the 

 most brilliant and widely heralded researches. Hum- 

 phry Davy had come to London in 1801, at the instance 

 of Count Rumford, to assume the chair of chemical phi- 

 losophy in the Eoyal Institution, which the famous 

 American had just founded. 



Here, under Davy's direction, the largest voltaic bat- 

 tery yet constructed had been put in operation, and with 

 its aid the brilliant young experimenter was expected al- 

 most to perform miracles. And indeed he scarcely disap- 

 pointed the expectation, for with the aid of his battery 

 he transformed so familiar a substance as common pot- 

 ash into a metal which was not only so light that it 

 floated on water, but possessed the seemingly mirac- 

 ulous property of bursting into flames as soon as it 

 came in contact with that fire-quenching liquid. If 

 this were not a miracle, it had for the popular eye all 

 the appearance of the miraculous. 



What Davy really had done was to decompose the 

 potash, which hitherto had been supposed to be elemen- 



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