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had published, in 1826, that, when several needles are placed at dif- 

 ferent distances above a wire through which the discharge of a Ley- 

 den battery is passed, they are magnetized in different directions, and 

 that by constantly increasing the discharge through a spiral, several 

 reversions of the polarity of the contained needles are obtained. 



It was, therefore, very important, before attempting further advances 

 in the discovery of the laws of the phenomena, that the results ob- 

 tained by M. Savary should be carefully studied ; and accordingly the 

 first experiments of the new series relate to the repetition of them. 

 The author first attempted to obtain them by using needles of a larger 

 size, Nos. 3 and 4, such as he had generally employed in all his pre- 

 vious experiments; but, although nearly a thousand needles were 

 magnetized in the course of the experiments, he did not succeed in 

 getting a single change in the polarity. The needles were always 

 magnetized in a direction conformable to the direction of the electri- 

 cal discharge. When, however, very fine needles were employed, 

 he did obtain several changes in the polarity in the case of the spiral, 

 by merely increasing the quantity of the electricity, while the direc- 

 tion of the discharge remained the same. 



This anomaly, which has remained so long unexplained, and which 

 at first sight appears at variance with all our theoretical ideas of the 

 connection of electricity and magnetism, was, after considerable study, 

 satisfactorily referred by the author to an action of the discharge of 

 the Leyden jar, which had never before been recognised. The dis- 

 charge, whatever may be its nature, is not correctly represented (em- 

 ploying for simplicity the theory of Franklin) by the single transfer 

 of an imponderable fluid from one side of the jar to the other ; the 

 phenomena require us to admit the existence of a principal dis- 

 charge in one direction, and then several reflex actions backward 

 and forward, each more feeble than the preceding, until the equili- 

 brium is obtained. All the facts are shown to be in accordance with 

 this hypothesis, and a ready explanation is afforded by it of a num- 

 ber of phenomena which are to be found in the older works on elec- 

 tricity, but which have, until this time, remained unexplained. 



The same action is evidently connected with the induction of a 

 current on its own conductor, in the case of an open circuit, such as 

 that of the Leyden jar, in which the two ends of the conductor are 

 separated by the thickness of the glass. And hence, if an induced 

 current could be produced in this case, one should also be obtained in 

 that of a second conductor, the ends of which are separated; and 



