14 BOHLIN, ON THE GALACTIC SYSTEM WITH REGARD TO ITS STRUCTURE. 
the regions far from the Milky Way very slowly and considerably less than for the 
brigther stars. But in the Milky Way the increase in number for the Herschelian 
stars seems, according to S., to be less — and is surely not greater — than would be 
the case, if the Herschelian stars were distributed according to the law holding for 
the stars up to the 11'/2 magnitude. From the whole inquiry, S. concludes that the 
Milky Way cannot be an independent phenomenon, but must cohere with the con- 
stitution of the stars system on the whole. 
It may, however, be pointed out that the Milky Way, considered as a portion 
of the general system of the stars, may nevertheless be of a comparatively singular 
structure and almost separated from the system of the brighter stars. Further 
examination fully proves that the Argelander-stars fail to show anything correspon- 
ding to the. varieties of density exhibited in the. peculiar structure of the Milky Way. 
Taking into account these several researches, the general result may conveni- 
ently be thus expressed.!' 
» If we should remove from the sky all the local aggregations of stars and also 
the entire collection which forms the clouds of the Milky Way, we should have left 
a scattered collection constantly increasing in density toward the Galactic belt. It 
does not yet seem possible to decide whether the agglomerations of the Milky Way 
lie on the boundary of the universe or not.» 
By treating more recent material, mainly containing star gauges by PICKERING, 
PARKHURST, HAGEN, and DE SITTER, added to the Herschelian gauges and the 
Carte du Ciel plates hitherto published, KAPTEYN has proceeded to investigate the 
distribution of stars even up to the 16” magnitude. The result arrived at is that 
of a symmetrical distribution of stars in respect to the Galactic circle, confined in 
the formula” 
in which 
N = number of stars of magnitude m and brighter per square degree, in Galactic 
latitude C; g, k, c being constants, which are pure functions of the Galactic latitude, 
for instance: 
k = 0.0460 — 0.0162 Cos 2 C. 
As this value of k is very small, the formula shows that very nearly: 
1 9. Newcomb, The stars, London 1902, pag. 276, 320. 
> "The Observatory, Vol. XXKI, N:o 393, pag. 74. 
