370 Mr. W. Sturgeon on the Theory of Ma gnetic Electricity. 



will not display its maximum of power. With pretty stout 

 bell-wire, and the length not exceeding twelve inches, I always 

 succeed. The battery which I employ is a single pair of me- 

 tals, sufficiently small to be placed in a pint pot. 



This novel and curious fact is one of those which bears di- 

 rectly on the subject in question, and in a theoretical point of 

 view is of a most interesting character. In practice, also, I 

 find that it is exceedingly useful ; giving a facility of manipu- 

 lation so desirable in the management of very large electro- 

 magnets, but which is not to be expected when all the extre- 

 mities of the wires arrive immediately at the copper and zinc. 



The theory of polar magnetic lines which I have advanced, 

 requires not two magnetic fluids, nor indeed is it favour- 

 able to that doctrine ; and if it be not fatal to the circulating 

 currents of Ampere, it will at least require them to be in mo- 

 tion in a great variety of planes, which that distinguished 

 philosopher never intended they should pursue. It is possible, 

 however, that electric currents are naturally attended with mag- 

 netic polarity, independently of that which has been supposed 

 to be excited in the wire ; but it is by no means so probable 

 that the existence of magnetic polarity is universally due to 

 the permanency of electric currents. Electric currents may very 

 possibly, either directly or indirectly, magnetize the terrestrial 

 globe; but we have no reason whatever to believe that such 

 currents are essential to give retention of polarity to steel. 



The introduction of polar magnetic lines into the theory of 

 electro-magnetism would simplify the explanation of the phe- 

 nomena, and reduce them to the principles of magnetics; and 

 experiments may be shown in both sciences which are favour- 

 able to such a conclusion, independently of any consideration 

 that would reconcile to identity the electric and magnetic 

 matter. 



If it can be admitted as an universal maxim in nature, that 

 when one species of matter is impregnated with, contains, or 

 is charged with another, the charged body must necessarily 

 be of a grosser texture than the substance with which it is 

 charged, or that the latter should be more subtle than the 

 former ; then it is possible that the magnetic matter, which is 

 the most subtle we are acquainted with in nature, may insinu- 

 ate itself into the pores of the electric; and the latter become 

 charged with the former, as decidedly, under some circum- 

 stances, as a piece of iron is naturally charged with them 

 both. 



I shall not, however, on the present occasion, advance further 

 into speculative suppositions of this kind, which, however 

 curious they may appear in themselves, are perhaps not of 



