240 MEMORIAL OF JOSEPH HENRY. 



Faraday in his "eighth series of Researches" (read before the 

 Royal Society June 5th, 1834), pointed out very fully the differing 

 actions of a single galvanic element giving a "quantity" current, 

 and of a series of elements giving an "intensity" current: thus 

 entirely confirming the results obtained by Henry more than three 

 years previously. 



In the Philosophical Magazine for November, L834, appeared a 

 paper by Faraday, "<)n a peculiar condition of electric and 

 magneto-electric Induction:" in which he notices as a remarkable 

 fact, that while a short circuil wire from a single galvanic element, 

 gives little or no visible spark, a long conductor gives a very sen- 

 sible spark. "If the connecting wire be much lengthened, then 

 the spark i- much inereased."f In his interesting research, Faraday 

 appeals t<> have entirely overlooked Henry's earlier labors in the 

 same field; — as contrary to his usual custom, he make- no allusion 

 t" tin' same results having been obtained, and published in Silliman's 

 Journal two year- and a half before.^ 



These observations were made l>v Faraday the subject of his 

 "ninth series of Researches," in a communication "On the influence 

 by induction of an electric current on itself:" read before the Roval 

 Society January 29th, 1835. In this paper he states: "The inquiry 

 arose out of a fact communicated to me by Mr. Jenkin, — which is 

 as follows: li' an ordinary wire of short length be used as the 

 medium of communication between two plates of an electro-motor 

 consisting of a single pair of metal-, no management will enable 

 the experimenter to obtain an electric shock from tin's wire: but if 

 the wire which surrounds an electro-magnet be used, a -hock is tilt 

 each time the contact with the electro-motor is broken." Having 

 varied the experiment, Faraday adds: "There was no sensible spark 

 on making contact, but on breaking contact there was a very large 

 and bright spark, with considerable combustion of the mercury." 

 lb found a similar result with the wire helix alone, — without its 

 magnetic core. "The power of producing these phenomena exists 

 therefore in the simple helix, a- well as in the electro-magnet, 



"Phil. Trans Roy. Soc. June 5, LS34, vol <xxiv. arts. 990-994, pp loo, tot) I 

 :,!■ ntat Researches in Electricity, vol. i pp 301, 302 



r /.. .t E. J>iii!osop?i. Mag Nov. 1834, vol. -v pp. 351, 152 



: Silliman's Am. Jour. Set. July, 1832. vol. wii. p. ins. above quoted. 



