(49) 



1 /^ ^ A x^ _ 



± 0".007 



I^ ^A/ ^ 



± 0".007 



The mean residuals found by testing the mean values for the 

 half-periods have about the same magnitude. 



For the entire period, as well as for both halves, the amplitudes 

 in X and in y prove to be considerably different. At the same time 

 the difference in phase clearly deviates from 90° = 91 days; it 

 amounts in the three cases to 117°, 124° and 105°. 



So the orbit of the yearly motion of the pole is a rather exeen- 

 tric ellipse, whose principal axes are inclined to the meridian 

 of Greenwich. 



The motion of the pole in this orbit is very approximately a sim- 

 ply harmonic one. The mean deviations of the observations are here 

 even considerably slighter than in the case of the 431-day motion. 



In order to investigate this elliptic motion more closely, I have 

 in the 3 cases turned the co-ordinate axes through an angle such 

 that they coincided with the principal axes of the ellipses. Doing this 

 it appeared in the first place that the major axes of the ellipses fall 

 east of the meridian of Greenwich and form with it the following 

 angles : 



