164 WEBER ON THE CONNEXION OF DIAMAGNETISM 



completely to the true internal condition of the magnet. In many- 

 investigations it is a great advantage to find a way furnished by 

 the ideal distribution towards the simple and complete union of 

 all the observed actions, without the necessity of making any 

 hypothesis regarding the interior of the body ; more particularly 

 when the causes of these actions remain unknown, and are still 

 to be investigated. From the fact itself, however, that the 

 knowledge of this ideal distribution, derived from observation, 

 affords a satisfactory and complete view of the phoenomena, it 

 evidently follows that from the observed phcenomena alone we 

 cannot proceed further than to the knowledge of this ideal distri- 

 bution, which however must of necessity be distinguished from 

 the knowledge of the true internal state of the magnet ; or, in 

 other words, that proceeding from the observed actions, we are 

 not in a condition to pronounce upon the actual distribution of 

 the magnetic fluid within a magnet, or upon the actual number, 

 strength, and arrangement of the electric currents contained 

 within it. 



The same holds good for the actions of a diamagnet ; from 

 the observation of its actions w^e might arrive at a knowledge 

 of the ideal distribution of the magnetic fluid on the surface of 

 the diamagnet, and thus find a substitute for the knowledge of 

 its true internal state ; but w-e could thus obtain no information 

 regarding the true internal condition, or the real nature of dia- 

 magnetism itself, its generation and modifications. To come 

 upon the trace of these, w^e must not limit ourselves to the con- 

 sideration of the actions, and the ideal distribution which depends 

 upon them ; but it is necessary to call in the aid of some other 

 consideration which is based upon a foundation independent of 

 these actions. 



All the possible causes of diamagnetism (like those of mag- 

 netism) may be divided in a general manner into internal and 

 external. The external cause (like the actions) is given by ob- 

 servationi it is the same for magnetism and diamagnetism, 

 namely, a magnetizing or electro-magnetizing force, determinate 

 in magnitude and direction. If, besides this external cause, that 

 which lies within the magnet itself were known, by the union of 

 both diamagnetism itself would be completely accounted for ; 

 and, inversely, we find a way open to the determination of the 



