( 416 ) 
2 mt . 2at 
fi cos TT + fo sin Er 
and we shall take constants for fi and fy. As a molecule is actually 
subjected to an alternating electric force, the amplitude and the 
phasis of which vary with the time, we get in this way a solution 
which will hold with approximation for a short time only ; but which 
will yet be sufficient to conclude from the condition at a given 
moment to that of a short time At after. The equation which we 
have to solve, is therefore reduced to: 
m — f (z— EE LEME TE (A Bee 
V dt 
or if we put a, =e («—a)): 
day e dar 
m == far + 
‚ 2at 
3 FI tan veel f Hemd ee ae 
The solution of this is: 
2 at 
2 mt eas 5 27 5 
in — Je + Dar cos — aje za SIN ra 
2 zt 
ih 
eas ; das on: 
By substituting in the equation for m De this value of az and 
by equating the coefficients of 
2 zut ne 2 mt 2 mt j 2 nt 
Cam COs —— e—kt sun —— cos —— an sin en 
Pe Vi i th 7 
separately to zero, we find the following four equations: 
An 27 
Az Mm GE Te — 1) — fan hee ya & LUT) Bane mk 7 7 a 
