Prof. Faraday on some Points of Magnetic Philosophy. 95 



netics have certainly been brought into a south condition by the 

 north end of the pole, recede from it ; and to apply these results 

 in the first instance to those obtained with bismuth in a vacuum, 

 before we assume a total change in principle, and yet an excep- 

 tional change as to substances, in the general law of magnetic 

 polarity, without any cause assigned than, or any supporting 

 facts beyond, the effect in question. 



Curved lines of magnetic force — dependence of the dualities. 



3323. The representative idea of lines of magnetic force which 

 I entertain, includes in it the thought of the curvature of these 

 lines, not as a merely convenient notion making the idea of the 

 lines more manageable, but as one flowing from and suggested, 

 if not proved, by the phsenomena themselves. It is in this point 

 of view that I proceed to consider it ; and as the proof of the 

 curvature is, in respect of principle, in the essential and neces- 

 sary dependence of the two qualities or parts of a dual force 

 upon each other (3324, &c.) ; and in respect of experiment, by 

 the numerous results supplied during the mutual actions of 

 magnets and magnetic bodies and the phsenomena of moving 

 conductors (3337, &c), I will consider eacn in turn. 



3324. There is no known case of one form or part of a dual 

 power existing otherwise than with, and in dependence on, the 

 other, which then exists simultaneously to an equivalent, i. e. an 

 equal, degree. In static electricity, where supposed electric fluids 

 are considered as being separated from each other, they are in 

 equal amount (1177.), are ever related to each other (1681.), 

 often by curved lines of force (1215.), and the existence 

 of the one electricity without the othei*, or in the smallest 

 degree of excess or deficiency, is absolutely impossible (1174.). 

 In the voltaic battery, or in the electric current produced 

 in any other way, as by thermo arrangements or inductions, 

 the current in one part of the circuit is absolutely the same 

 in amount and in dual character as in another; and in the insu- 

 lated, unconnected voltaic battery, where the sustaining power 

 is internal, not the slightest development of the forces, or of 

 cither of them, can occur until circuit is completed, or induction 

 allowed at the extremities ; for if, when there is no circuit, the 

 induction be prevented, not merely no current, but no stock of 

 electricity at the battery poles ready to produce a current can be 

 evolved in the slightest degree. In like manner 1 am fully per- 

 suaded that the northness and southness of magnetism (in what- 

 ever they may be supposed to consist) cannot exist alone; — nor 

 without exact proportion to each other ; — nor without mutual de- 

 pendence upon each other; — but that they are subject to the 

 mutual relation and dependence of all dual force. 



