354 TWO MAGNETIC POLES. [SECT. xxx. 



dence between the fracture of a magnet and that of an 

 electric conductor ; for, if an oblong conductor be electrified 

 by induction, its two extremities will have opposite electri- 

 cities ; and, if in that state it be divided across the middle, 

 the two portions, when removed to a distance from one 

 another, will each retain the electricity that has been 

 induced upon it. The analogy, however, does not extend 

 to transference. A body may transfer a redundant quantity 

 of positive electricity to another, or deprive another of its 

 electricity, the one gaming at the expense of the other; but 

 there is no instance of a body possessing only one kind of 

 polarity. With this exception, there is such perfect corre- 

 spondence between the theories of magnetic attractions and 

 repulsions and electric forces in conducting bodies, that 

 they not only are the same in principle, but are determined 

 by the same formulae. Experiment concurs with theory in 

 proving the identity of these two unseen influences. Hence, 

 if the electrical phenomena be due to a modification of the 

 ethereal medium, the magnetic phenomena must be owing 

 to an analogous cause, and therefore, notwithstanding the 

 high authority of M. Poisson, they must also be attributed 

 to the redundancy and defect of only one fluid. 



