AN OBSTACLE ON A TRAIN OF ELECTRIC WAVES. 
305 
is the principal part of the integral 
j —IK (Ilj + li) 
+ + + .)2 + (H^+Br;+ .) 
that is, writing 
ky) = r]', 
it follows that 
^ OD 00 
I _ ^-2 g-‘/<(R, + R)-^(r^cosH + ’?''^)(Ki-i + R-‘) 
, _ 00 — 00 
provided that the point Q, in which OP cuts the conducting surface, is not near to 
the curve of contact of the tangent cone from O to the surface with the surface. 
Evaluating the above integral, the value of I is given by 
I =: PPl g-iK(R, + R) 
IK COS R + ’ 
and therefore 
a„ = — 
^^2 ^tK(Vt Ki R) 
V (Ili + R) cos 
^0 — 
^^2 gC«(Vi-Ri-R) 
V (Ri + R) C0S(^ 
IK^ gC«(V(-R.-R) 
{(/^o + + nl,) {y-r]o) + n {-q^z - 
{(^^0 + + nQ {x - ^o) + n (I’oZ - i^x) }/RRi, 
{n(ryoa?-^o2/)}/RRi- 
Now 
and 
whence, since 
V(Ri + R)cos(^ 
^o/Ri = (a'-^o)/R, = (y“’?o)/R, Co/Ri = (2 -Co)/R. 
(/£o + wryo + 5'iCo)/Ri = -coS(^, 
= ^/(Ri + R). 0«-^o)/R = a;/(Ri + R), 
a, 
tK 
,2 g«(V«-K,-R) 
V Ri + R Ri + R 
iK-^ a; 
V Ri + R Ri + R 
To = 0- 
Again, the components of the magnetic force at the point P due to the oscillator are 
/ K 
n = 
0 g«(V«-K,-R) 
V0y Ri + R 
/8' =t 5 -’ r--0^ 
va* Ri+R 
2 R 
VOL. CCXII.—A. 
