28 Mr. T. K. Chinniayam on the Flow of 



a point P / (fig. 1) due to this alone is from (6) 



( sin g ) 



1 /\ j n , , s tt\ 



= — o — \/ -7 cos ( -(r-cn+Tf 



since « ( = P'OY) is small. 



r' = P / = (r 1 — a^) sec a =(7*2 — a#) sec 20 (approx.). 

 r ' + a0 = r 1 (l + 20 2 ), where r 1 = P'M'. 

 Also if P'Q = r, ct = 2r0/(r-a0) approx. 



If E, H be the resultant electric and magnetic intensities 

 at P', 



E=cosn(£ — -)— tcGOSntt -J 



and > > 



H= cosn/ £ J — kcosw ( £ ) 



1 A f /, r' + aO\ 7T * 



-wv? cos i w r~H"4r 



If &x, & 3 , £3 be unit vectors measured^ along r l5 r, and r' 

 respectively, the time-mean of the flow of energy is found 

 to be given by 



^ = h [l-« cos ~2t(P-k' Cos ^ 2rtf»+ |Y] 



+ & 2 K 2 — k cos- 2r0 2 + K/c' cos - 



+ £ 3 |~/c'2 _ tf cos (^ 2r0 2 +?)+ KK ' cos ^1 , 



1 A 



«' being written for ,- — a / -7. 

 & 2?ra V r' 



Resolving the vectors along and perpendicular to the 



