Mr. W. Sturgeon on the Theory of Magnetic Electricity. 35 



Under these considerations it will readily appear, that all 

 the elemental magnetic particles enveloping the north portion 

 of a regularly magnetized bar of steel will have their south 

 poles directed towards the surface of the metal, and con- 

 sequently all their north poles will be directed outwards in 

 every part of the arrangement. Precisely the reverse of this 

 distribution of poles will take place in the magnetic matter 

 enveloping the south portion of the steel ; so that in this case 

 the north poles will be directed towards the south portion of 

 the metal, and consequently all the south poles will be turned 

 outwards. 



If now we contemplate the arrangement which would take 

 place in the vicinity of one polar portion only, of a piece of 

 steel, supposing it to be uninfluenced by a pole of the other 

 kind, we shall discover, by the laws of magnetics, that the 

 polar affections of the enveloping magnetic matter will arrange 

 the particies of which it is composed, into radial polar lines, 

 emanating from every part of the steel surface ; for, as each 

 individual line will be formed by the attachment of a conse- 

 cutive series of dissimilar poles of elementary particles, the 

 remote extremities of all these virtual magnetic lines will 

 become similarly polarized ; in consequence of which, they 

 will have a constant tendency to diverge from each other. 

 Hence if we be contemplating the north polar portion of the 

 steel, the remote extremities of the virtual magnetic lines will 

 be north polar-, but if it be the south portion of the steel which 

 comes under consideration, the remote extremities of the 

 magnetic lines will be south polar. Hence also, the lines of 

 magnetic action which envelop a bar of steel displaying two 

 poles only, may be divided into two distinct classes or sy- 

 stems ; one of which may be called north polar, and the other 

 south polar. If it were possible that either of these systems 

 of magnetic lines could be displayed separately and indepen- 

 dently of the disturbing force of the other system, those lines 

 would be perfectly straight, or without flexure in every part 

 of their course; that is, they are naturally right lines-, and if 

 the magnetized body were a sphere, the virtual polar magnetic 

 lines would radiate in right lines from every part of its. surface. 

 (See fig. 1. and 2. Plate I.) 



Hitherto I have endeavoured to explain what I consider 

 radiating magnetic polar lines, emanating without obstruction, 

 from a magnetized piece of steel, under the supposition of its 

 being unipolar on every part of its surface : but as no piece of 

 steel, of whatever form it may be made, has yet been known 

 to exhibit one uniform polar state, but on the contrary, each 

 piece of magnetized steel invariably displays a plurality of 



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