

ELECTRO-MAGNETISM. 



Electro-Magnetism very recently discovered. Oersted's Experiments at Copenhagen. The Law 

 according to which the Needle is deflected. The Law of Attraction and Repulsion of Electric 

 Currents. Supposes Electric Currents circulating round the Globe. Arago shows that the con- 

 ducting Wire has Magnetic Properties. Needles magnetized by the Electric Current. The 

 Variation of the Attraction of the Current at different Distances determined. Laplace reduces 

 this Result to an analytical Formula. The whole Body of Electro-magnetic Phenomena reduced 

 to analytical Calculation. Faraday's Researches. Rotation imparted to Mercury by means of the 

 Magnet and Electric Current. The Multiplier or Galvanometer. Its Construction and Applica- 

 tion. The Earth affects Electric Currents in the same Manner as it affects Magnets. Ampere's 

 Theory of Terrestrial Magnetism. Researches of M. de la Rive. Magnetizing Power of the 

 Current at different Distances, and the Law of its Variation. The Effect produced by transmit- 

 ting it through Metals. The undulatory Theory of Electricity similar to that of Light. Thermo- 

 Electricity. Thermo-Electric Effects observed by Professer Seebeck. His Experiment with An- 

 timony and Copper. Researches of Yelin, Marsh, and Gumming. Oersted and Fourier construct 

 a Thermo-Electric Pile. Becquerel decomposes Water with such an Instrument Thermo-elec- 

 tric Sca-'o -* Mtals. 



