viii Contents. 



Page 



Cavendish, . ... 51 



Michell discovers the law of magnetic force, . . . .54 



The two-fluid theory : Coulomb, . . . . .56 



Limited mobility of the magnetic fluids, . . .58 



Poisson's mathematical theory of electrostatics, . . .59 



The equivalent surface- and volume-distributions of magnetism : 



Poisson's theory of magnetic induction, . . .64 



Green's Nottingham memoir, . . . . .65 



CHAPTER III. 

 GALVANISM, FROM GALVANI TO OHM. 



Sulzer's discovery, ... . .67 



Galvanic phenomena, ....... 68 



Rival hypotheses regarding the galvanic fluid, , . .70 



The voltaic pile, ....... 72 



Nicholson and Carlisle decompose water voltaically, . . 75 



Davy's chemical theory of the pile, ..... 76 



Grothuss' chain, . . . . . . .78 



De La Rive's hypothesis, . . . . . .79 



Berzelius' scheme of electro-chemistry, . . . .80 



Early attempts to discover a connexion between electricity and 



magnetism, . ... 83 



Oersted's experiment : his explanation of it, . . .85 



The law of Biot and Savart, . . . . . .86 



The researches of Ampere on electrodynamics, . . 87 



Seebeck's phenomenon, . . . . . .90 



Davy's researches on conducting power, . . . .94 



Ohm's theory : electroscopic force, . . . . .95 



CHAPTER IV. 

 THE LUMINIFEBOUS MEDIUM, FROM BRADLEY TO FRESNEL. 



Bradley discovers aberration, . . . . .99 



John Bernoulli's model of the aether, .... 100 



Maupertuis and the principle of least action, . . . 102 



Views of Euler, Courtivron, Melvill, .... 104 



Young defends the undulatory theory, and explains the colours of 



thin plates, ... ... 105 



Laplace supplies a corpuscular theory of double refraction, . . 109 



