Effects produced by the Motion of Electrified Bodies. 235 



/^> / 5R 2 a 2 \ d 2 1 pep 2 

 r ~~ 5 V 6 2/^R 1 " 3 B? 

 5R 2 a\ d? 1 



~5~ (,"6" ~~ ¥y dx~ohj R 



5 \ 6 2 / dx dr R 



Now if a, /3, 7 be the components of the magnetic induction 

 at the point (#, y, z), 



u= — - — =0 



dy dz ' 



n d¥ dR uepz d 1 



_ r/Gr dF _ /*epy _ d 1 • 



Hence we see, by symmetry, that if the sphere move with velo- 

 city q parallel to the axis of y, the corresponding values would 

 be 



d 1 

 ^-^dzTL' 

 0=0, 



d 1 



and if it moved with velocity r parallel to the axis of z, the cor- 

 responding values would be 



d 1 

 a=fier fyB? 



a d 1 



7 = 0. 



Hence, if p, g, r be the components of the velocity of the 

 centre of the sphere parallel to the axes of x, y, z respectively, 

 the components of magnetic induction are 



d 1 d 1\ 



""^V^R *dz II 



Q ( d i d.'i\ 



/ d 1 rf i\ 



7= K^r-^r; ; 



