CONTENTS. ix 



ART. PAGJK 



magnet (a position which we shall call "end-on"): the 

 magnetic energies are supposed to be collected in the 

 poles; and the attractive or repulsive force to vary 

 inversely as the mth power of the distance: to find the 

 angular momentum impressed on the disturbed magnet. 

 Attractions will be represented in the diagrams by con- 

 tinuous lines, repulsions by interrupted lines . . .24 



15, In the same arrangement, to find the tendency of the 



action of A to produce a motion of translation of B .27 



1G. The disturbing magnet is end-on towards the center of the 

 disturbed magnet, which is broadside-on ; to find the 

 angular momentum impressed ...... 28 



17. In the same arrangement, to find the tendency of the action 



of A to produce a motion of translation of B . . .31 



18, To find the tendency of the action of A upon B in the 



simplest cases of parallelism of the two magnets . . .31 



19. Remarks on the computation of these quantities by the 



method of Potentials . , . . . . .33 



20, Investigation of the cases of Articles 14, 15, 16, 17, 18, on 



the supposition that magnetism is not confined to two 

 poles of each magnet, but is disseminated according to 

 some law through its whole length; being entirely red 

 magnetism on one side of the center, and entirely blue on 

 the other side, with similar laws of distribution. Defini- 

 tion of the "magnet-power" of a magnet . . .36 



21, Investigation of the action of a magnet, whose poles are very 



widely separated, upon a needle, whose center is in the line 



of those poles, and whose axis is inclined to that line . . 39 



SECTION IV. 



ON TERRESTRIAL MAGNETISM, AS ACTING IN THE HORIZONTAL PLANE 

 AT EACH PLACE OF OBSERYATJON. 



Articles 2234. Pages 4276. 



22. Definition of Local Magnetic Meridian, and Magnetic Vari- 



ation or Declination; instruments and methods for ascer- 

 taining roughly the Declination : Azimuth Compass : obser- 

 vation of Sun's azimuth: Variation Theodolite: Declination- 

 Charts H 



