CH. xxxvi. ELECTRO-MAGNETISM. 367 



CHAPTER XXXVI. 



SCIENCE OF THE NINETEENTH CENTURY (CONTINUED). 



Electro-magnetism Oersted Ampere Arago Faraday Thermo- 

 electricity Seebeck Schwabe Spots on the Sun Sabine 

 Sun-spots and Magnetic Currents Electric Telegraph Wheat- 

 stone Cooke Steinheil Morse Bain. 



Oersted discovers the Effect of Electricity upon a 

 Magnet, 18^9. We left the history of electricity at p. 

 262, at the rjoint where Volta had shown in 1800 that two 

 different metals joined by a wire and placed in acid and 

 water will set up a current of electricity flowing from the 

 one metal to the other, and back through a connecting 

 wire. Every galvanic battery, that is, an apparatus for 

 producing electricity by chemical action, is made on 

 this principle. You will hear of Grove's battery, Bun- 

 sen's battery, DanielFs battery, and many others, all of 

 which have been invented in the present century ; but all 

 these are only different and more perfect methods of carry- 

 ing out Volta's discovery. The next great step in the study 

 of electricity was made by Oersted, Professor of Physics at 

 Copenhagen, in 1820, twenty years after the invention of 

 the voltaic pile. 



Hans Christian Oersted was born in 1777, and died in 

 1851 ; he was a very eminent man, and wrote many works 

 in Latin upon chemistry and magnetism, but the one dis- 

 covery which has made him famous was that of electro^ 



