Mr. Faraday's Experimental Researches in Electricity, 353 



With respect to the explosion of the shell being audible at 

 a great depth, the experiment at Geneva is not any proof; for 

 if I recollect aright, that was superficial sound, not perpen- 

 dicular sound, — a difference of considerable consequence. 

 Palace Yard, Sept. 23, 1833. T. R. F. 



LI X. Experimental Researches in Electricity. — Third Series. 

 By Michael Faraday, D.C.L. F.R.S. M.R.I. Fullerian 

 Prof. Chem. Royal Institution, Corr. Mem. Royal Acad, of 

 Sciences, Paris, Petersburgh, SfC.Sfc. 



[Concluded from p. 262.] 



III. Magneto-Electricity, 



343. Tension. — T^HE attractions and repulsions due to the 

 ■P- tension of electricity have been well ob- 

 served with that evolved by magneto-electric induction. M. 

 Pixii, by using an apparatus, clever in its construction and 

 powerful in its action*, was able to obtain great divergence of 

 the gold leaves of an electrometer f. 



34-4. In motion: i. Evolution of Heat. — The current pro- 

 duced by magneto-electric induction, can heat a wire in the 

 manner of ordinary electricity. At the British Association of 

 Science at Oxford, in June of the present year, I had the 

 pleasure, in conjunction with Mr. Harris, Professor Daniell, 

 Mr. Duncan, and others, of making an experiment, for which 

 the great magnet in the museum, Mr. Harris's new electro- 

 meter (287- ), and the magneto-electric coil described in my 

 first paper (34.), were put in requisition. The latter had been 

 modified in the manner I have elsewhere described J, so as to 

 produce an electric spark when its contact with the magnet 

 was made or broken. The terminations of the spiral, adjusted 

 so as to have their contact with each other broken when the 

 spark was to pass, were connected with the wire in the elec- 

 trometer, and it was found that each time the magnetic con- 

 tact was made and broken, expansion of the air within the in- 

 strument occurred, indicating an increase, at the moment, of 

 the temperature of the wire. 



345. ii. Magnetism. — These currents were discovered by 

 their magnetic power. 



346. iii. Chemical Decomposition. — I have made many en- 

 deavours to effect chemical decomposition by magneto-electri- 



+ Annates de Chimie, I. p. 322. f Ibitl - n *. p. 77- 



% Phil. Mag. and Annals, N.S. 1832, vol. xi. p. 405. 



Third Series. Vol. 3. No. 17. Nov. 1833. 2 Z 



