[ 824 ] 

 LXXXY. Intelligence and Miscellaneous Articles. 



CORRECTION TO MR. H. BATEMAN's PAPER ON THE REFLEXION 

 OF LIGHT AT AN IDEAL PLANE MIRROR MOVING WITH A 

 UNIFORM VELOCITY OF TRANSLATION. 



O^ P" ^^ ^ v0 ^' xviii. ^ ec « 1909) the equations should be 

 EJdy'dz' + EJdzUlv' + EJdx'dy' - cKJdx'dfJ -cKy'dt/'dt' - cK z 'dz'dt ' 

 = T&jdydz -\- THjfdzdJB-t-T&zdxdy —c\l x dxdt — c U s dijdt — 6K z dzdt. 



C— V , J <r — v <r — tr 



cr — v* <r — ir <r — v 



-?h;=-(b,- 4 :hA 



e;+^v=-(e.,+ i;h, / ), 



Relative to an observer moving with velocity v the components 

 ol the electric and magnetic force are 



E;' = 



: E r , 





e;= 



c 2 — 



-X- 



v 2 J 



e; = 



c 2 + 



c 2 — 



"X- 



These 



give 



e; 



E, 



E y - V H, E,+ -H, 



V'-S" V'-r 





V'-,'. 



v^T 



Hence the above equations indicate that the sums of the 

 tangential components of the electric force, and of the normal 

 components of the magnetic force, relative to the moving observer 

 are zero at the surf.ice of the mirror. The conditions for a perfect 

 reflector are thus satisfied. H. Bateman 



