CONTENTS. xv 



SECTION XXXI. 



Electro-Dynamics Reciprocal Action of Electric Currents Identity of 

 Electro-Dynamic Cylinders and Magnets Differences between the Action 

 of Voltaic Electricity and Electricity of Tension Effects of a Voltaic- 

 Current Ampere's Theory Dr. Faraday's Experiment of Electrifying 

 and Magnetising a Ray of Light Page 316 



SECTION XXXII. 



Magneto-Electricity Volta-Electric Induction Magneto-Electric Induc- 

 tion Identity in the Action of Electricity and Magnetism Descrip- 

 tion of a Magneto-Electric Apparatus and its Effects Identity of 

 Magnetism and Electricity The Submarine Telegraph . . . . 322 



SECTION XXXIII. 



Electricity produced by Rotation Direction of the Currents Electricity 

 from the Rotation of a Magnet M. Arago's Experiment explained 

 Rotation of a Plate of Iron between the Poles of a Magnet Relation of 

 Substances to Magnets of three Kinds Thermo-Electricity . . 330 



SECTION XXXIV. 



Magnetism a Dual Power Antithetic Character of Paramagnetism and 

 Diamagnetism The Earth Paramagnetic Properties of Paramagnetic 

 Bodies Polarity Induction Lines of Magnetic Force Currents 

 of Electricity induced by them Proved to be Closed Curves Analogy 

 and Identity of Electricity and Magnetism > Terrestrial Magnetism 

 Mean Values of the Three Magnetic Elements Their Variations in 

 Double Progression proved to consist of Two Superposed Variations 

 Discovery of the Periodicity of the Magnetic Storms The Decennial 

 Period of the Magnetic Elements the same with that of the Solar Spots 



Magnetism of the Atmosphere Diamagnetism Action of Electro- 

 Magnetism on Paramagnetic, Diamagnetic Bodies, and on Copper, very 

 different Proof of Diamagnetic Polarity and Induction Magne- 

 crystallic Action Effects of Compression, Heat, and Cleavage on Mag- 

 netic Bodies Mutual Dependence of Light, Heat, Electricity, &c. &c. 



The Conservation of Force and the Permanency of Matter Primary 

 Laws of Nature Definition of Gravity not according to that Law 

 Gravity only the Residual Force of a Universal Power Magnetism of 

 the Ethereal Medium 335 



SECTION XXXV. 



Ethereal Medium Comets Do not disturb the Solar System Their 

 Orbits and Disturbances M. Faye's Comet probably the same with 

 Lexel's Periods of other three known Acceleration in the mean 

 Motions of Encke's and Biela's Comets The Shock of a Comet Dis- 

 turbing Action of the Earth and Planets on Encke's and Biela's Comets 



Velocity of Comets The Comet of 1264 The great Comet of 

 1343 Physical Constitution Shine by borrowed Light Estima- 

 tion of their Number 358 



