STAR STKEAMS AND STAR SPRATS. 
407 
stars to associate themselves into streams and sprays, the star 
sprays being ordinarily of the form illustrated in Fig. 1. It 
would be quite impossible for me to convey by means of pictures 
any adequate idea of the persistence with which these peculi- 
arities of structure were renewed, especially in certain parts 
of the chart. Indeed, it would be absolutely necessary to 
include a much larger portion of the heavens than could 
here be conveniently pictured, to show the most significant 
feature of all, the manner namely in which the sprays are 
divided and sub-divided. 
Now the point to be chiefly noticed here is, that so far as 
a priori considerations are concerned, one would be led to 
expect that no very marked signs of stream-formation would 
be shown among stars down nearly to the tenth order of mag- 
nitude. For the further we increase our range of vision, 
the more likely must we be, it would seem, to obtain a 
view in which the actual relations of the stars are confused 
by seeming combinations, due to the accidental agreement, 
in general direction, of star-groups at very different orders of 
distance. For either there is or there is not a general uni- 
formity of star-magnitude (within certain limits). If there 
is such uniformity, so that the fainter stars are in reality as 
large (on the average) as others, but more distant, then it is 
certain that amongst the stars dealt with in Argelander’s charts 
there are in all directions stars at very different distances ; stars 
therefore not in reality associated, but which yet, being seen in 
nearly the same direction, are brought into seeming juxtaposition. 
If, on the other hand, there is not among the stars, even in a 
general sense, any approach to uniformity of magnitude, then 
we may be even more completely deceived ; for certain near 
stars which are really very small (relatively) may be brought, 
not merely into seeming juxtaposition with more distant stars, 
but even to a seeming equality of magnitude. 
This being remembered, it was to be expected that the 
distribution of the stars included in Argelander’s charts would 
correspond much more closely to a real chance distribution of 
so many points over a hemisphere, than where we considered 
only a comparatively small number of stars belonging to the 
leading orders of magnitude. Moreover, even assuming the 
point which I am now endeavouring to prove, viz., that the 
stars are in many cases arranged into the form of streams and 
sprays, it would yet seem highly probable that all signs of these 
streams and sprays would be obliterated, simply because streams 
and sprays of stars would probably lie at very different distances 
in all directions, and the configuration of the nearer streams 
would be blended with and confuse the configuration of the 
more distant. 
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