70 G. PLARR ON THE SOLUTION OF THE EQUATION Vpgp=0 ? 
If we designate by fy the angle between ¢’ and the normal, an angle which 
may vary from 0° to 180°, we have : 
fee TVev_ TVeae 
dU See BS 

So that 
a Ww BE Fao ~ 960). 
We will calculate W, and E—W for the same values of E as before, and 
we easily’get by 

We G a =(= = =~ (phy 
Bos js Oy =e he 
Wy = Ty 2 W,.= > p) Mg wat: 
3 3Q’ h 
(55) Waa | ae wy | 
2 2 Q 4 
Wo=() 
W,,=9 Wisk 
This gives forv, as oA=h,A, Dp=hp, wv=hey 
3 3 
Vy =p5hid, Vu = Shop : Vy =ohy 
{ vu =(@+ap € w= B+5 € 
'\3 
v.=| o— s) |: 
Vy = we V2 = (a -— hye 
\ 
N 
Namely, these results are obtained as follows : 
Q=Q’ + Seae= —Ayheh,— Ee? 
For E=hy, e-("F) 

hyp—hy? 
2 
(Q) Saar Iahashs —h, 
(2) = — BL Ahaha + (82h +72) | 
— Bhs +h,) = —"E 
