1918-19.] An Electron-Transference Hypothesis, etc. 
217 
(/) The Contribution to the Atomic Refractive Index of the 
Positive Electrification. 
In H. A. Lorentz’s work the contribution to the molecular refractive 
index due to the vibration of the positive electrification is ignored. It is 
interesting to determine the value of this contribution. 
When we ignore the vibration of the positive electrification our 
equations become 
1-38 
X§|= — -TrX 2 e £r* 
1-39 
m 
2,£r = -X/xe-^£r. 
1-40 
1*41 
1-42 
(t- mp 2 )^ j i r = - Xfxe. 
X' = -7rNX/xe 2 /(£ - my 2 ). 
O 
4 , T w E -se 
A S {1) w „7rX n W e . 7 > 
s 3 0 t-my 2 
_ WX 0 T(E — se) 
p T — c 
where A S {1) = value of A s when the vibration of the sphere of positive 
electrification is neglected. 
W¥ 
Af%^ 0 .T(E-se). 
1-43 
1*44 
and 
Hence 
. 7 - ac 
A s -A s «> RT 
As E _ se _ (sd _ E) s y^ c 
sbT>ac y and so approximately. 
A _ A (W 
-“■s -^s 
s 2 bd _ s 2 h , 
EE = "T‘ iU 
if s =f= 0, 
1-8.1. 107’ 
K1 ?z 
Equation 144 shows that 
1*45 
if s = 0. 
A<»>A„ 
and hence the contribution of the vibration of the positive electrification is 
negative. It is also evident that when s=f= 0 this contribution is small, 
being of order 
s 2 h 
n 
.10 2 , and is of the order 
1 . 8 h 
n 
. 10~ 5 when s = 0. 
