CONTENTS. 



SECTION I. 



PHYSICAL EXTENSION OF MAGNETISM, AND LIMITATION OF ITS 

 TREATMENT IN THE PRESENT WORK. 



Articles 1, 2. Pages 1, 2. 



ART. P.AGB 



1. DISSEMINATION of magnetism through many components of 



the Earth, and probable cosmical extension of magnetism . ] 



2. Our accurate knowledge of magnetism is limited to the 



magnetism of iron, steel, and the Earth, to which this 

 work will be confined: with allusion finally to galvanism 

 and thermo-electricity ....... 2 



SECTION II. 



PROPERTIES OF STEEL MAGNETS. 

 Articles 313. Pages 323. 



3. The steel magnets will be supposed to be slender bars ; 



usually, they will be supposed to be straight . . . 



4. Definition of a steel magnet ; the definition sometimes 



applies to iron bars 



5. Size of magnets most convenient for experiments ... 



6. Mounting of magnets for experiments 



7. The opposite ends of a magnet have different properties. 



Explanation of the terms "red" and " blue " magnetism, 

 and of the symbols employed to represent them. Allusion 

 to horse-shoe magnets 



