( 371 ) 
OA 0 0A Ox Leis 
(35) beoor) Heinen) (at eon sinpy & ein, vopo( ) nae simpy 
a4), VIN aD oD/ 
which give the normal equations: 
/ [\eosdasinno( 5 ), + sind verl SE a) | dA-- 
el + leon) + sind eol) | Voegen) eehm 52) | dD 
en [cotsinn (2 =) -sindgcosp9(S4) {sinks sinp 
(36) 
eesti )-tsindsronr( 5%) | lookin )--sindyrora( 2) | ile 
+ beesten 05) sind gcosp‚, EARN dD 
| 
is 
coehyinpo( 5 7) einen 5) {sindosinpo| 
0 
Let us now assume, as was supposed above, that we take the 
mean of the proper motions of the stars situated closely together 
and continue working with these as if they were real proper motions. 
The effect of thus taking means of a considerable number of motions 
will of course be, that the peculiar motion, which takes place in 
various directions, is eliminated for the greater part, so that the 
mean proper motion found will, with some approximation, represent 
the mean parallactic motion for the region under consideration. 
If we distinguish the values obtained by taking means by dashes 
over the letters, then we will evidently have for the various regions, 
with greater or smaller approximation (ef. (8)): 
and consequently 
igp=—=0 
U 
If first we take only zones of constant A, and if farthermore 
hi, : : 
we assume that the mean secular parallax — is, with some approxi- 
0 
ats 
