412 
POPULAR SCIENCE REVIEW. 
account of this marvellous band of stars, accords excellently 
with the description given by Sir John Herschel and others 
who have most carefully studied the galaxy. More especially 
is it suggested by the aspect of the Milky Way in the southern 
heavens. For there the continuity of the zone, on which so 
much stress had been laid is shown to be interrupted by a broad 
dark rift, a feature wholly inexplicable on the theory that the 
Milky Way is shaped like a cloven flat disc. And over the 
whole region from Argo, over the feet of the Centaur, to Sagit- 
tarius and Scorpio, the Milky Way as pictured by Sir John 
Herschel presents an appearance far more closely according 
with the theory that the Milky Way in this region forms a 
gigantic spray of stars than with any other that has been pro- 
pounded. In the northern heavens, the faintness of the Milky 
Way causes it to appear more uniform in structure; but even 
in the northern heavens, as has been well pointed out by 
Professor Nichol, it is only on the most cursory examination, or 
when the Milky Way is studied under unfavourable circum- 
stances, that it can be regarded as a simple zone. But it is 
well worthy of notice that in my chart of 324,198 stars, the 
Milky Way reveals itself (through the mere aggregation of 
stars down to the 9^th order) as a congeries of streams, with 
branching extensions, of which only the commencement can 
be recognised as more or less marked projections, in the best 
pictures of the northern parts of the Milky Way. 
It remains to be noticed, in conclusion, that the nebular 
system also shows the most marked tendency to stream-forma- 
tion when isographically charted, as in the series of charts 
which illustrate my paper on the distribution of the nebulae, in 
Vol. xxix. of the Monthly Notices of the Astronomical Society. 
The tendency to stream-formation is more especially to be 
noticed among the southern nebulae. It is worthy of remark 
that, whereas the southern nebular streams converge upon the 
Magellanic Clouds, the northern nebular streams seem to extend 
towards the outlying streams of the Milky Way, as it appears in 
my chart of 324,198 stars. The evidence of a real association 
between stars and nebulae is singularly strengthened by these 
peculiarities of arrangement. 
