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XIII. Experimental Researches in Electricity. — Fourteenth Series. By Michael 

 Faraday, Esq., D.C.L. F.R.S. Fullerian Prof. Chem. Royal Institution, Corr. 

 Memh. Royal and Imp. Acadd. of Sciences, Paris, Petersburgh, Florence, Copen- 

 hagen, Berlin, Gottingen, Modena, Palermo, 8^c. S^c. 



Received June 21, 1838. — Read June 21, 1838. 



§. 20. Nature of the electric force or forces. §.21. Relation of the electric 

 and magnetic forces. §. 22. Note on electrical excitation. 



§. 20. Nature of the electric force or forces. 



1667- X HE theory of induction set forth and illustrated in the three preceding se- 

 ries of experimental researches does not assume anything new as to the nature of the 

 electric force or forces, but only as to their distribution. The effects may depend 

 upon the association of one electric fluid with the particles of matter, as in the theory 

 of Franklin, Epinus, Cavendish, and Mossotti ; or they may depend upon the asso- 

 ciation of two electric fluids, as in the theory of Dufay and Poisson; or they may not 

 depend upon anything which can properly be called the electric fluid, but on vibra- 

 tions or other affections of the matter in which they appear. The theory is unaffected 

 by such diff^erences in the mode of viewing the nature of the forces ; and though it 

 professes to perform the important office of stating how the powers are arranged (at 

 least in inductive phenomena), it does not, as far as I can yet perceive, supply a single 

 experiment which can be considered as a distinguishing test of the truth of these 

 various views. 



1668. But, to ascertain how the forces are arranged, to trace them in their various 

 relations to the particles of matter, to determine their general laws, and also the spe- 

 cific differences which occur under these laws, is as important as, if not more so than, 

 to know whether the forces reside in a fluid or not ; and with the hope of assisting in 

 this research, I shall offfer some further developments, theoretical and experimental, of 

 the conditions under which I suppose the particles of matter are placed when exhibit- 

 ing inductive phenomena. 



1669. The theory assumes that all the particles, whether of insulating or con- 

 ducting matter, are as wholes conductors. 



1670. That not being polar in their normal state, they can become so by the in- 

 fluence of neighbouring charged particles, the polar state being developed at the in- 

 stant, exactly as in an insulated conducting mass consisting of many particles, 



MDCCCXXXVIII. 2 M 



