INTRODUCTION 
XXIX 
The equation gave An — ^0034 ± '.'08. The corresponding Am is +'0078. The 
following adjustment-equations to determine centennial corrections were then 
formed with weights carefully studied from the probabilities of the case. 
Weights. Obs. 
10 A'm — A\ — A E a — — '.'37 
1 A E a = + .30 
8 AX = .00 
2 A'm = + .78 
The observed absolute terms of the first and last equations come from the solar- 
motion discussion already mentioned, in the manner indicated in the foregoing. It 
may be of interest to examine some of the details in determination of Ak and An. 
From the final normal equations founded on the motions of 5413 stars, involv¬ 
ing also the coordinates of solar motion, the values of Ak and Am already cited were 
determined. Dividing the material into zones parallel with the equator, we have: 
Comp. 
.32 = 
— '.'32 — — Ak 
+ .79 
+ .06 
+ •53 
(C) 
Zone. 
Limits. 
— A /c 
+ A n 
n 
// 
I 
— 10 to + 10 
— .62 
+ .16 
II 
+ 10 to + 30 
— 10 to — 30 
— .20 
+ .28 
III 
+ 30 to -f 5 ° 
— 30 to - 50 
- -55 
+ .38 
IV 
+ 50 to + 90 
— 50 to — 90 
— .10 
+ -44 
All 
— 90 to + 90 
- -37 
+ *34 
Arranging in zones parallel with the galaxy, we have: 
Zone. 
Limits 
Galactic Lat. 
— A£ 
+ A 11 
// 
n 
V 
O O 
— 19 to -f- 19 
- -23 
+ -39 
VI 
+ 19 to + 42 
— 19 to — 42 
- .34 
+ .14 
VII 
+ 42 to + 90 
— 42 to — 90 
- -52 
+ .42 
The determination of Ak in zone III, and especially in IV, has, of course, 
small weight. The persistence in sign and average amount of these quantities in 
the separate determinations seems rather marked and tends to inspire confidence 
in the mean. Moreover, the final normal equations, as derived from fi and /a', 
separately, give for An: 
WT. P. E. 
Aw from right ascensions, +['38 17 ±'.'16 
An from declinations, -I- .33 53 ± .09 
