TRANSACTIONS OF SECTION A. 401 
is R.A. 342" 49*-97, Decl. + 25°69" 163, It has a large proper tiotion—viz., 
—0*018, —0’88 in R.A. and Decl. respectively. The separate results deduced 
from the five plates are as follows :—0’004, + 0'"114, 0':072, +0’051, +0192, 
from the mean of which we have as the parallax of this star, relatively to 
seventy-five comparison stars of mean magnitude 11:0, 
: + 0085 + 0'-022. 
The mean probable error of the parallax of one of the comparison stars as 
derived from the five plates is +0013, 
At a later date two plates, 6B and 54B, representing the region around 
Weisse 6", 128 were sent to Professor Kapteyn at his request. The magnitude 
of this star is 8:4, and its position for 19050 is R.A. 6°9™55s-05, Decl. 
+ 44°-44"43'"4, It has a proper motion of —0::028 and —0’"33 in R.A. and 
Decl. respectively. The separate results deduced by him from these two plates 
are +07°136 + 0018 and +0’067 + 0''-020, or, taking the mean, we haye as the 
parallax of this star: 
+0'7102 + 0'-013. 
For the probable error of the parallax of one of the 166 comparison stars we 
have, using Kapteyn’s notation (see Groningen Publications No. 12); 
No. of Plate Ps P, p,’ 
6B + 0-018 + 0’""032 + 0’-028 
54B + 0:020 + 0°035 + 0°027 
The remainder of the plates will be measured and discussed at the Radcliffe 
Observatory and some progress has already been made with this work. The 
results for the double star, L1 6888 and 9 ( = 5 443) appear of sufficient importance 
to lay before the Section. This is a double star the components of which are of 
the magnitudes 8°5 and 8°8 respectively, and have a large common proper motion 
amounting to +0*053 in R.A. and —1/-24 in Declination. In this case the 
parallax factor is only 2°21—the normal factor being 4—and we find p3= +0032, 
p, = + 0'055, and p,’= + 0-080. 
On this plate there are 191 stars suitable for measurement. Grouping them 
according to magnitude, we find the following results : 
Mean Parallazes. 
Limits = * No. of 
M Parallax Stars 
ag. 
Brighter than 8-5 +0'110 5 
85— 95 + 0:067 7 
9-5—10°5 + 0-017 | 25 
Fainter than 10°5 —0:010 154 
The central star 3 443 is most probably a binary system, and taking the mean 
of the results found for the separate components, we have as the parallax of this 
system relatively to 189 comparison stars—z = + 0':10 + 0'”-02, 
6. Two curiously similar Spectroscopic Binaries. By J. 8. PuasKerr 
and W. E. Harper. 
1909. DD 
