TWO DEGREES OF THE NORTH POLE. 57 
while in the process of making the comparisons variations from his 
values were suspected, it did not seem advisable to delay the conclu- 
sion of this work long enough to make a thorough investigation, 
especially as the main object in view was the formation of a catalogue 
of positions. Further, in most cases only a single comparison was 
made, and the adopted values may, therefore, be subject to some 
error. Hence neither the photographic nor the visual magnitudes 
are to be considered as final. 
The chart used for comparing the photographic positions with the 
sky was made by plotting the rectangular codrdinates of the stars 
upon millimeter cross-section paper. By means of this chart a few 
errors in the reduction were detected by the disagreement of plate 
with sky. 
Table XVI, which follows, contains the final catalogue. The head- 
ings of the several columns explain themselves. The rectangular 
coérdinates and the precession coefficients were determined according 
to the method of Fabritius given in Publication 1, p. 58. The identi- 
fication with the Carrington catalogue and with the Durchmusterung 
was made by using the above formulas and carrying the stars back to 
1855, the epoch of both catalogues. 
