60 
For the sectors 315°, 135° and (in a lesser degree) 75° the great 
positive value of c, approaching 7, giving a great value of / that 
raises also the value of 2, causes a strong maximum for A, rapidly 
decreasing on both sides; so we find here a condensation of stars 
in space. The empirical data upon which it depends, consist in a 
strong curvature of the A-curve, i.e. a strong increase of the stars 
of the 8% magnitude, not continuing in the same manner for the 
9'h magnitude. As in this case small variations in c bring about 
great variations in A, it is necessary to examine the reality of these 
condensations as to the uncertainty of the starnumbers NV, which 
have by chance distribution a mean error u = WN. Therefore for 
these sectors corrections corresponding to this uncertainty were applied 
in the direction of diminishing c and then the computation has been 
repeated '). Now the results are: 
long. a b c 0, h k l 
15° 0.304 0.489 + 0.0095) 12.39 9.869 — 0.111 + 0.013 
135 0.138 0.455 —+ 0134 11.90 9.803 —0.145 + 022 
315 0.266 0.446 —+ 0219 11.17 0.062 —0.154 + 060 
The condensation at 135° has wholly disappeared ; the great density 
at 75° joins the dense parts in sector 45°; the condensation at 315°, 
however, remains evident and does not disappear even by greater 
corrections to log N. Unless, perhaps, the scale of magnitudes strongly 
deviates here from the mean galactic zone, this condensation must be 
considered as real. 
A deviation in opposite sense is shown by the sectors 165°, 190° 
and (in a smaller degree) 225°, where c and / are negative. Because 
the number of stars increases from the 8th to the 9 magnitude 
at an unusual rate — it is known that on this side of the sky the 
stars of magnitude 9—10 are strongly condensed over a fourth of 
the galaxy — we find that the space density at first, in the vicinity 
of the sun, decreases rapidly, but at a greater distance ceases to do 
so; whether it increases afterwards, cannot be decided by these data. 
The results of the Selected Areas for the 6 Northern sectors are 
collected in the next table, where » denotes the number of the 
areas used (each being ‘/, square degree). 
1) The coefficient c will be diminished, if N (6,5) and N (9,0) are increased, 
N (8,0) is diminished. A small calculation showed that we get an even chance 
if for the value of this increase or diminution we take 0,6 u. 
