348 Experimental Researches in Electricity. 



ing more generally still, progressive forces. And second, 

 the term arrangement, by which is understood a local adjust- 

 ment of particles or fluids, or forces not progressive. 



These definitions premised, ordinary electricity now comes 

 under consideration ; and in regard to its tension, little more 

 is necessary than the simple statement of its existence, since 

 the effects due to it, are among the fundamental and most 

 familiar of the science. The attractions and repulsions exhi- 

 bited by it are identical in kind, though different in degree, 

 with those exhibited between the two poles of the voltaic bat- 

 tery, and it is quite unnecessary to dwell longer on the point. 



The heating power of common electricity, when passed 

 through wires or other substances, is perfectly well known. 



Until Faraday examined the subject, the magnetic power 

 of ordinary electricity was by no means distinctly establish- 

 ed, and the experiments of M. Colladon, of Geneva, on the 

 point, were not received as decisive in consequence of their 

 being accompanied by certain suspicious circumstances. 

 The magnetic power of an electric current appearing to de- 

 pend on time being allowed for its action, it was necessary 

 to devise some means by which the almost instantaneous 

 transmission of ordinary electricity should be checked, and 

 the intensity of the charge reduced within manageable li- 

 mits without the quantity being affected. To the retard- 

 ing power of bad conductors, Faraday first looked, with 

 the hope of producing this result, and combining this power, 

 with the influence of a discharging train of enormous extent, 

 being nothing less than the entire fabric of the metallic 

 gas and water-pipes of the city of London, he succeeded 

 perfectly in throwing the discharge of ordinary electricity 

 into the form of a current, and then found, in full accordance 

 with his expectations, that it possessed magnetic influence 

 equal to that of a voltaic current of the same intensity. 

 Deflections of the galvanometer were readily produced by 

 discharging a Leyden jar through a wet thread about four 



