478 THE INTELLECTUAL RISE IN ELECTRICITY. 



tended across the channel ; for, in the spring of 1733, 

 Charles Francois de Cisternay Dufay 1 began his famous 

 work. 



Dufay was then thirty-five years of age, and perhaps as 

 widely different from Gray as one man can be from an- 

 other. To the broadest general culture and knowledge of 

 the world he united a charming personality, a keen wit, 

 and exquisite tact, the last never better exhibited than 

 when, instead of antagonizing Gray, he managed to con- 

 vert the sensitive philosopher into a cordial and communi- 

 cative friend and colleague. He had been educated as a 

 soldier, and was a lieutenant in the Picardy regiment at 

 the age of fourteen; but his natural taste was for scientific 

 study, and not at all for military life. He exchanged 

 arms for diplomacy, and the latter for science. In his 

 brief lifetime of forty-one years (he died in 1739) he made 

 himself a chemist, an anatomist, a botanist, a geometri- 

 cian, an astronomer, a mechanician, an antiquary, and an 

 electrician, and in every one of these varied capacities 

 shone with unusual brilliancy. The French Academy 

 then recognized only six subjects as worthy of public dis- 

 cussion, namely, chemistry, anatomy, botany, geometry, 

 astronomy, and physics. Dufay, says Fontenelle, 2 in his 

 celebrated eulogy, was the only man of his time who con- 

 tributed to the Academic annals investigations in every 

 one of these branches. His early studies on the Bologna 

 stone and phosphorus resulted in the discovery that all 

 stones containing salts of lime become luminous on cal- 

 cination; his essay on the magnet, published in 1728, the 

 phenomena of which he regarded as in accordance with 

 the Cartesian theory, epitomizes all existing knowledge 



1 See Dufay's eight original memoirs. Histoire de 1' Academic Royal 

 des Sciences, Paris, for years 1733, 1734 and 1737. 



2 Fontenelle: Eloge de M. Dufay. Hist, de 1'Acad. Roy. des Sciences, 

 1739- 



