880 The Uranometria Argentina. 
being subtracted from the observed number in the sky, leaves 
a system of distribution which may be represented by the ex- 
pression 2,,=ab” within the limits of the errors of observation. 
. The accordance thus obtained holds good for the stars of 
both hemispheres down to the lowest limits of magnitude for 
which trustworthy enumerations exist; and this whether we 
employ the numbers of the Durchmusterung, of Argelander's 
and Heis’s Uranometries, or of this present work. 
7. The form of the expression 3,,=ab” is that which corres- 
ponds to the hypothesis that in general the stars are distributed 
at approximately equal distances from one another, and are 0 
approximately equal intrinsic brilliancy. It is, however, not 
requisite for its applicability that their distribution be equable 
in all directions, but only that their number be proportional 
to the volume of the spherical shell within which they are con- 
tained. 
corresponds to the light ratio 0:4028 for descending, or 2°4827 
for ascending, magnitudes. 
‘Then follows a description of the parts of the Milky Way, 
with its rifts and ramifications, and the gradations and contrasts 
of light. With this is a careful determination of the medial 
points and the breadth of the stream, the position of the 
galactic circle, and the numbers of stars on the two sides of 
the circle. : 
“ Inferences of some cosmological importance are deducible 
from the tables just given. It cannot escape notice that the 
part of the Milky Way which lies between 160° and 225° of 
galactic longitude, or from 6" to 8" of right-ascension, is much 
the broadest of all; this corresponding to the region of widest 
separation of the branch-circles in the undivided portion of the 
stream. Moreover the narrowest parts are from 3" to 5$” and 
from 104" to 12" of right-ascension, or, roughly, in the galactic 
55° t 
longitudes 105° to 150° and 270°. These regions, 
