( 50 ) 



ellipse 1890— 9G 19" East. 

 » 1890—92 29° » 

 » 1893—96 10° » 



Further wc find for the components of' the motion in tlie direction 

 of the principal axes: 



«-Sept. 28 „ i-Sept. 28 



1890-96 u' = + 0". 121 cos 2 7t //= — 0",057«w2;i 



^ 365 -^ 365 



«-Sept. 23 «-Sept. 23 



1890—92 ,r = 4- 0".136 cos 2 71— *^ »/= — 0".065mt2;i 



' 365 -^ 365 



«-Oct. 1 , «-Oct. 1 



1893—96 ;* = + 0".114(w2;ï y = — 0".055s»( 2;r 



365 ' 365 



8o the motion is dircd, like that of 431 days, and the times «g 

 express the times of ti'aiisit through the positive halves of the 

 major axes. 



The motions found for tlie two half-pcM'iods do not differ so much 

 that there is any guarantee for a real difference existing. It is my 

 opinion therefore, that for the present we must assume as the most 

 probable orbit for the yearly motion of the pole an ellipse, whose 

 major axis lies 19° east of the meridian of Greenwich and whose 

 semi-axes amount to 0''.12 and 0".06. 



As early as 1894 Chandler had found i) an excentric orbit for 

 the yearly component ; so on the whole I can fully confirm his result. 

 His ellipse however has a greater inclination (45° east of the meri- 

 dian of Greenwich) and also a somewhat greater excentricity (semi- 

 axes 0".16 and 0".05) than mine. 



The results of absolute determinations of zenith distances are so 

 liable to systematic perturbations of a yearly period, that to my idea 

 they cannot contribute to a more accurate knowledge of the yearly 

 term of the motion of the pole. 



The results obtained by the Horrebow-method too are certainly not 

 quite free from these perturbations and particularly there would be 

 reason to fear for them the influence of the inclination of the strata 

 of air either in or outside the observing room (see a. o. Albrecht 



') Astron. Journal, No. 32-3, 329 and 403. 



