| 
U 
2 
then. we find 
dy ci OE 1 6 | 
en (Tine Ee ee Says Se ao Nee KN De ZM 29 
dd J ip J RET Pe J ( ) 
\ 
ErnsreiN ') has the same equation, only his righthand member is 
ay’. The difference is caused by the difference in the arbitrary 
condition introduced to compiete the determination of the gq. The 
integration of (29) is easier than of the corresponding equation of 
Einstein, which leads to elliptic functions. We find easily 
1 ey 
. are aie C08 (JD 0), 
JP. Pi 
where ¢, and w are constants of integration, and 
DE . 7 
g=1—-—— ita Wan eRe eos EN 
5 Pi 
If now we put 
Sy: a Ee pek 2 Po Die 
LIP e= en a— 9 AAT 
P 
then we have 
Sea AN nae SCA aD 
and 
1 ie | + e cos (gd — w) (32) 
r p 
The orbit is thus an ellipse of which the perihelion moves in the 
direction of the orbital motion. The displacement of the perihelion 
i de sa 3A? 
during one revolution is Ay -- 22 => 5 2a. This same value has 
been found by Einstein. The numerical value is for the different 
planets, in one century: 
Mercurius do = + 42".9 edo = + 8".82 
Venus 8.6 + 0.05 
karth — 3.8 + 0.07 
Mars | + 0.13 
If the elements a and p are introduced in (24), this becomes 
ld ; HOS eee eA 
pr =tvuvr (ts Ee -— ) barstte 
dt a p r 
1) 1. c. page 837, formula (11). Drosre of course finds the same formula as 
Einsrer, and he integrates it by means of elliptic functions. 
