( 266 ) 
The values, found for Aus have been used in computing the 
corrections, to be applied to the P.M. in right ascension. 
This correction, A w., supposed to be = 0, when A ws was calcu- 
lated, is derived from the formula 
Zr’ A us = sin x 
AM Se 
? 
= cos x 
first for each spectr. Type, and each belt separately and taking 
A gt constant from OP to 3", from 3" to 6", a.s.o. Afterwards the 
different values for the same R. A., but different types and declina- 
tions, were combined, with weights proportional to the numbers 
of stars. 
The final values are 
| 
| 
| Qh—gh | 3h—6h | Gh—gh oon [9a 5e115»—184|10o1n| 21m —on 
| 
| | | | 
Ni == Beet 4-005 5008 0000-0001 00100 
| | | | 
Putting the weight proportional to cos d instead of proportional 
to n, we get 
Aha = 
| | | 
—-0s0006,6 4.980000 81-4-050008.2 -+-0s0066.3 —0s0001 3|—0,00097 9,006.6! —0s.0000.7 
| | | | 1 | | 
mean probl. err. 0s.00042. 
As appears from the prob. errors, they are hardly to be consid- 
ered real. 
With these corrections to the proper motions, the coordinates of 
the apex have been calculated. The formulae used for the purpose, 
the derivation of which is easily seen, are 
sin 0 — cos A sin D pas sin (a — A) cos eS 156 Sen 
sin? À sin® À 
where «=AA= corr. to be applied to the R. A. of the apex. 
y=AD= oe engin nn ey Deel. AE) n 
2 (rtA us sin ZX) 
ig 6 = — : ae : 
r =(v+ Aus cos 7) 
