THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



MARCH 1855. 



XXIV. Further Observations on associated cases, in Electric Induc- 

 tion, of Current and Static Effects. By Professor Faraday, 

 D.C.L., F.R.S. &c * 



MELLONI, whose loss science must deeply feel, was engaged 

 in the latter part of his life in investigations relating 

 to static electricity, especially concerning induction, conduc- 

 tion, &c. He desired, in reference to these and the results I had 

 published respecting the charge of, and conduction by, subter- 

 raneous and subaqueous insulated wires f, to know whether there 

 was any difference in the time of transmission through such wires, 

 of currents having greater or less intensity, i. e. of currents from 

 batteries of different numbers of plates. I applied to Mr. Latimer 

 Clark on the subject ; and he with the same earnestness as on 

 the former occasion, sought and seized the opportunity of making 

 experiments of the like kind, and gave me the results, which I 

 sent to Melloni. The latter published them with some observa- 

 tions in an Italian Journal (whose title is not on the paper 

 which he sent to me), and soon after he was suddenly removed 

 from us by death. As Mr. Clark's results are not yet known 

 in this country, I have thought that a brief account of them 

 would be valuable. His process records, by the printing tele- 

 graph of Bain, the results obtained with 768 miles of copper 

 wire covered with gutta percha, and laid in the ground in four 

 lines between London and Manchester, so connected that the 

 beginning and the end of the whole length was in London. 

 The following are his words, dated May 31, 1854: — 



" I have tried a few experiments on the relative velocities of 

 currents of different intensities, and I enclose you some strips of 



* Communicated by the Author. 



t Royal Institution Proceedings, i. 346 ; or Phil. Maj;. 185-1, vii. p. lf'7- 



I'lnl. Mag. S. 4. Vol. 9. No. 58. March 1855. M 



