ELECTRICITY AND MAGNETISM 



by the brilliancy of the discharge when made through 

 charcoal. 



"Repetition of the experiments with a battery of 

 one hundred and twenty pairs of plates produced no 

 other effects; but it was ascertained, both at this and 

 at the former time, that the slight deflection of the 

 needle occurring at the moment of completing the con- 

 nection was always in one direction, and that the 

 equally slight deflection produced when the contact 

 was broken was in the other direction ; and, also, that 

 these effects occurred when the first helices were used. 



' ' The results which I had by this time obtained with 

 magnets led me to believe that the battery current 

 through one wire did, in reality, induce a similar cur- 

 rent through the other wire, but that it continued for 

 an instant only, and partook more of the nature of the 

 electrical wave passed through from the shock of a 

 common Ley den jar than of that from a voltaic bat- 

 tery, and, therefore, might magnetize a steel needle al- 

 though it scarcely affected the galvanometer. 



11 This expectation was confirmed ; for on substituting 

 a small hollow helix, formed round a glass tube, for the 

 galvanometer, introducing a steel needle, making con- 

 tact as before between the battery and the inducing 

 wire, and then removing the needle before the battery 

 contact was broken, it was found magnetized. 



" When the battery contact was first made, then an 

 unmagnetized needle introduced, and lastly the battery 

 contact broken, the needle was found magnetized to 

 an equal degree apparently with the first; but the poles 

 were of the contrary kinds." * 



To Faraday these experiments explained the phe- 



243 



