( 321 ) 
1 1 2m i an 3 
aT 27 r ae ey 
and f= Ane js p Men C08: (¢— =) + Maa sin miter) 
0° My ay =) 4 : zl 2)! 
esas asl yl Cos T7 y2 sin. pe (oF 
92 dey Liye 2) 4 Ms di 20 1: =) 
cme ae a 28 
ey oe a 2a r _ 2% im 
= Ve 22 Ee ns COS. oh (¢ —y) a Ma chi Er (é is eo oe 
In this the influence of absorption has been neglected. In a 
complete theory we should have to calculate it by examining to 
what influence the vibration of every molecule is subjected by the 
radiation of every other molecule. Then it would be necessary to 
take into account the influence of the damping, which the vibrating 
molecules experience, and the quite unknown influence of the colli- 
sions. Here I shall confine myself to assume that the distur- 
bances, when they have propagated over the unity of length, are 
reduced to e—* of their original amount. Then we have to multiply 
with e#" every term under the integral sign in the expression 
for f. 
For points for which # is great compared with the wave length, 
we may write by approximation: 
L /2n\2 (ec ( 2 7 r 2 n PA) 
Sl —— M. lt) M,9 sti alt el En 
/ pst al ; } Ne: pT mie 
2 7 r _ 2n r\) ey 
+ |My cos. a (« — =) 4. My» (ger tS ae (re + 
2 n 2 | #2 
a(t wy) + Mea sins (t— Wirn 
2 2. 
— | Mas cos. t — = + Myo sin a(t -— F) 1 dt. 
So the modulus for the probability, that [A] lies between the 
limits [A] and [+ ¢/\], becomes: 
23* 
