( 636 ) 
and we must investigate what form the function E now assumes.* 
As we have supposed that 
= n s + q , 
the terms of the order h in the equations of motion would become 
y -f (2>n x — q) 2 y. 
Because 
than A 2 in the equations. 
may write for the latter: 
y + 4nY y — 4n x qry. 
If we thus take the above expression for x and y as first approxi- 
mation, then we must admit in the function R besides the term 
— cl 3 x~y also a term 2 n x gy z . 
In the expression 
— d % x*y -j- 2 n x Qy- 
we substitute the above expressions for x and y and omit the terms 
containing t explicitly. In this way we arrive at ■- 
:v ,«, 
2 N 
where again JST is put tor n t -{- q = 2 n x . 
The equations which serve to determine the «’s and pi’s become: 
_J = _2 Nm x a x «, 
dt iia 
[ = ~Q'h -f 
We again see that 
for which reason we put: 
a x -f « s — constant ; 
