ELECTKOLYSIS, 



SECTION I. 



THEORY. 



CHAPTER I. 



PRELIMINARY NOTIONS. 



Magnetism Energy Hypotheses on Electric Phenomena Electric Potential 

 Electromotive Force Electric Current Current Intensity Electric 

 Resistance Electric Conductivity Theoretical Electrical Units Prac- 

 tical Units Ohm Ampere Volt Dyne Watt Ohm's Law Elec- 

 trical Work. 



MAGNETISM. Before entering upon the subject of the ex- 

 amination of the laws of electrolysis, it is necessary to briefly 

 review certain notions on magnetism and on the principal 

 phenomena accompanying the production of electricity. 



The magnetic property of the natural substance oxide of iron, 

 Fe 3 O 4 or loadstone of attracting iron filings is very gene- 

 rally known, as also the fact that this property can be trans- 

 mitted to bars of steel and artificially to soft iron. What is 

 less generally known is that the magnetic and electric phe- 

 nomena exert upon each other mutual reactions giving rise 

 to the powerful electric currents used in industry. 



The steel magnets, the only ones in use in the small 

 laboratory apparatuses, are sometimes straight, or in the form 

 of a horseshoe or of a half-circle, or, again, in the shape of a 

 lozenge or of an arrow ; sometimes they are made into cylin- 

 drical rings entirely closed, &c., &c. ; but whatever their shape 



