( 267 ) 
when A ws only was applied and 
(r+ Aus sin vy — A pa cos 0 cos 7) 
ZT (wt A wscos y + A ua cos 0 sin y)’ 
yo = 
on applying both corrections. 
Dividing each belt in eight parts, of 3h in R.A., and including 
all the stars (2503 in number) of which the proper motion does not 
exceed 0".30, six sets of equations of condition of the form (1), of 
40 equations each, were obtained. From each set was derived a 
value for A A and A D. 
The weight of 9 proves to be proportional to the respective 
number of stars. The O's, having negative denominator, evidently 
should be taken in the 24 or 3rd quadrant. 
The coordinates of the apex, found in this way, are: 
A D 
Type I. corr. A ws 268°.3 + 2°.4 EN ay lede EC 
A Maand Aus. 212.1 2 2:93 316 EA 
Type Il. A ús 219 0. 4338 33.9 + 2.8 
A waand A us 270.6 + 4.0 34.8 Sa Be 
Types I and IL Ass "26952 1.7 343 se aN 
together Aweand A ws 274.2 + 1.7 3... b Se se 
Besides, values of A and D have been derived in perfectly the 
same manner from 151 stars with annual P. M. > 0".3, after 
applying A us to these P. M’s. 
For each of these 151 stars an equation of cond. (I) was con- 
structed. The result is: 
A =O HE IAA Dd AL De ah 
These results confirm what Mr. PANNEKOEK wrote in 1895 
(Bullet. Astr. XII p. 196): “Si Von a égard à ces corrections des 
apex calculés, on peut en tirer la conclusion qu’ils ne montrent pas 
d'indication évidente d'un mouvement relatif entre les étoiles à spec- 
tres de types différents.” 
NeEwcoMB goes a little farther yet (Astron. Journal X VII, p. 390): 
“The centres of gravity of two great classes of stars scattered through 
the celestial sphere will be at rest relatively. — I believe this hy- 
pothesis safe still when the classes differ by spectral type, as the 
positions of the apex in both cases are fairly well the same.” 
The calculations, of which the results only are given here, will 
shortly be published in extenso. 
Groningen, November 1899. 
