In this neighbourhood the other stream reappears, passing over a region very rich in stars.

We see now the greatest extent of the Milky Way, towards this part of its length, ever visible in our latitudes--just as in spring we see its greatest extent towards Monoceros and Argo.
[Illustration: PLATE IV.] I may note here in passing that Sir John Herschel's delineation of the northern portion of the Milky Way, though a great improvement on the views given in former works, seems to require revision, and especially as respects the very remarkable patches and streaks which characterise the portion extending over Cepheus and Cygnus.

It seems to me, also, that the evidence on which it has been urged that the stars composing the Milky Way are (on an average) comparable in magnitude to our own sun, or to stars of the leading magnitudes, is imperfect.

I believe, for instance, that the brilliant oval of milky light in Cygnus comes from stars intimately associated with the leading stars in that constellation, and not far removed in space (proportionately) beyond them.

Of course, if this be the case, the stars, whose combined light forms the patch of milky light, must be far smaller than the leading brilliants of Cygnus.