THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FIFTH SERIES.]^|f ^^ 



J ANn 70 7* 



JANUARY 1897. 



I. Electrical Notes. 

 By Arthur Schuster, F.R.S. 



III. On the Magnetic Force acting on Moving 

 Electrified Sjiheres*. 



SCIENTIFIC opinion inclines to the view that electric 

 conduction in gases and liquids is a process of molecular 

 convection, the moving particles being charged with definite 

 quantities of electricity. If we follow out that hypothesis 

 we meet with a number of problems in which it becomes 

 necessary to calculate the effects of magnetic forces on 

 charged and moving electrified particles, and also the mutual 

 magnetic effects of two or more such particles. To some 

 extent the old question of the behaviour of current 

 elements is thus renewed, although the recognition of 

 " displacement currents " has diminished, if not entirely 

 removed, the ambiguity of the problem. 



The question of the magnetic field produced by a moving 

 electrified sphere and the magnetic reactions on the sphere 

 was first attacked in an important paper by J. J. Thomson f . 

 Some time afterwards it was reopened by Heaviside J, who, 

 " whilst agreeing with J. J. Thomson in the fundamentals,''' 

 was " unable to corroborate some of his details/' J. J. Thom- 

 son returns to the same problem in his ' Notes on Recent 

 Researches in Electricity and Magnetism.' As regards the 



* Communicated "by the Author. 

 t Phil. Mag. vol. xi. p. 227 (1881). 

 X Ibid. vol. xxvii. p. 324 (1889). 



Phil. Mag. S. 5. Vol. 13. No. 260. Jan. 1897. B 



