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Proceedings of the Royal Society of Edinburgh. [Sess. 
The stars whose proper motions are considered are well distributed over 
the whole sky : 157 are within 52° of the North Pole, the proper motions 
being taken from the Groombridge Catalogue ; 165 are within 50° of the 
South Pole, the proper motions being taken from the Cape Astrographic 
Catalogue (only such stars being used as are found in two earlier cata- 
logues), from Professor Porter’s Catalogue - of Stars with large proper 
motions (Cincinnati Observatory Publications, No. 12), and the Cape General 
Catalogue for 1900. 
Jf 
The remainder are within a belt extending 30° N. and S. of the equator, 
and are taken from Professor Porter’s Catalogue. They are distributed in 
R.A. as follows : — 
R.A. 22 h -2 h 154 stars R.A. 10 h -14 h 167 stars 
R.A. 2 -6 126 stars R.A. 14 -18 124 stars 
R.A. 6 -10 92 stars R.A. 18 -22 121 stars 
These 1100 stars have been treated as belonging to eight different areas, 
and their proper motions found as projected respectively on the tangent 
planes at the poles, and the tangents at the equator at the points 0 h , 4 h , 8 h , etc. 
