767 
c is a constant coefficient which by an appropriate choice of units 
can be taken to mean the velocity of propagation in vacuo of 
electromagnetic waves. The other symbols used have already been 
defined in 8 1. above. 
§ 3. To make further progress, let us suppose that 
•E.==0; H z = 0; P z = 0 (1) 
and that the remaining components 
K, E >, Il n H y , P, and P y (2) 
.all contain the factor 
e l *(•-?•) (3) 
where b denotes a complex constant. We have a plane transverse 
wave, propagated in the direction of the axis of z. Equations (6), 
§ 1., reduce to 
P x = ME X — inbV>E y (4a) 
P y = MÈ y + mbVE x . (4 b) 
Let us consider now a right-handed circularly polarized wave and 
a left-handed circularly polarized wave. Then we can write 
Py = + tPx Î Ey = ± lE x (5) 
where we are to read -(-or — in the right-hand member accord¬ 
ing as we are dealing with the right-handed or the left-handed 
vibration. With this assumption it follows from (4) that 
^ = ^ = J2f±nbZ’. ( 6 ) 
With the help of (1), (2)—(3) and of (6) we deduce from equa¬ 
tions (I), § 2: 
+ bcH y ==E a {l-{-4:n( t ®r±nb2>)} (7 a) 
'—bcH x =E y {l+4.n(£f± nb%>)}. (7b) 
On the other hand, from equations (II) in Art. 2 we obtain, by 
means of our present assumptions (1) and (2)—(3): 
— mbcE y = mH x + (%>E X — inb%0E y ) (8a) 
c 
A TTf} 2 
-\-mbcE x = inH y -\-=^-{‘PE y -\-mb < 2PE x ) (8 b) 
c 
2 * 
