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III. Experimental Researches in Electricity. — Ninth Series. By Michael Faraday, 

 D.C.L. F.R.S. Fullerian Prof. Chem. Royal Institution, Corr. Memh. Royal and 

 Imp. Acadd. of Sciences, Paris, Petershurgh, Florence, Copenhagen, Berlin, 8§c. S^c, 



Received December 18, 1834, — Read January 29, 1835. 



§. 15. On the influence by induction of an Electric Current on itself: — and 

 on the inductive action of Electric Currents generally. 



1048. XHE following investigations relate to a very remarkable inductive action 

 of electric currents, or of the different parts of the same current, and indicate an 

 immediate connexion between such inductive action and the direct transmission of 

 electricity through conducting bodies, or even that exhibited in the form of a spark. 



1049. The inquiry arose out of a fact communicated to me by Mr. Jenkin, which 

 is as follows. If an ordinary wire of short length be used as the medium of commu- 

 nication between the two plates of an electromotor consisting of a single pair of 

 metals, no management will enable the experimenter to obtain an electric shock from 

 this wire ; but if the wire which surrounds an electro-magnet be used, a shock is 

 felt each time the contact with the electromotor is broken, provided the ends of the 

 wire be grasped one in each hand. 



1050. Another effect is observed at the same time, which has long been known to 

 philosophers, namely, that a bright electric spark occurs at the place of disjunction. 



1051. A brief account of these results, with some of a corresponding character 

 which I had observed in using long wires, was published in the Philosophical 

 Magazine for 1834*; and I added to them some observations on their nature. 

 Further investigations led me to perceive the inaccuracy of my first notions, and 

 ended in identifying these effects with the phenomena of induction which I had been 

 fortunate enough to develop in the First Series of these Experimental Researches -j-. 

 Notwithstanding this identity, the extension and the peculiarity of the views respect- 

 ing electric currents which the results supply, lead me to believe that they will be 

 found worthy of the attention of the Royal Society. 



1052. The electromotor used consisted of a cylinder of zinc introduced between the 

 two parts of a double cylinder of copper, and preserved from metallic contact in the 

 usual way by corks. The zinc cylinder was eight inches high and four inches in 

 diameter. Both it and the copper cylinder were supplied with stiff wires, surmounted 

 by cups containing mercury ; and it was at these cups that the contacts of wires, he- 



* Vol. V. p. 349. t Philosophical Transactions, 1832, p. 126. 



MDCCCXXXV. G 



