( :iJ4 J 



obtained fur the i)enocl 1904.6 to J 907.5, which pei-iod iminediately 

 precedes the peitnihatioji in 1907. As co-ordinates of the mean pole 

 1 found : 



§= + 0."001 7i= + 0."040 



ill ,t!,ootl accordance with those nienlioiied al>ove. The elliptical co- 

 ordinates Itecanie 



./'. = — Ü."075 sin ih, — "0 1 9 cos If, 1 

 y^ = -f 0."00l si,, ,|v — 0."058 <r^^• If', ^ • • ■ ' ^-> 

 in which \]\ has l)een counted from the l)eginning of the year. 



This yearly component of the motion was supposed to be constant 

 for the whole jjcriod 1904.0 till 1911.0 and I diminished the .rand 

 // resulting from the observations with these ,i\ and //,. From the 

 residual values for ^ -\- ,i\, and j^ -f- //.^ I computed, adopting for the 

 length of the period the value found abo\e : 434.1 days, two ellipses, 

 1" for the period 1904.0— 1907.0 and 2Mbr 1908.0— 1911.0. I found : 



,,,. , ,, ^ I ^ -- -r "-"0 '3 X., = 0."n5 sin (iK ^ 199.°2) 



1904.0 - 1907.0 ' ' 



I 7^ = -f O."044 //, = 0."121 sin (if, -f 288.°3) 



v.. being counted from 1904 



I ^ =: I- < ."008 .V, = 0."252 sh, (iK, + 280.^1) 



1903.0 1911.0 ) ^ ' ^ '- ^ '' 



I >^ = 4- O."037 V, ^ 0."249 sin (if., + 10.°4) 



If., being counted from 1909.0. 



Both orbits are so nearly circular, that I substituted for them the 



two following circles; 



I .*,-, = 0."118 sin{ii\ + 179.°;;) , 

 1904 0—1907.0 ' , ^^' ^ , 



y., =z 0.ni8co.«(if, -f 179.°3) 



... (3) 

 1 .r., = 0."250 sin (if, -f 188.°7) ' 

 1908.0 — 11)11.0 ' ' ^^' ^ 



\ _//., = 0."250 cos (if, + 188.°7) 



i|\, being counted for both from 1907.5. 

 For these formulae (3) I have not yet derived the mean error 

 Observ. — Comput., but when we considei-, that Albrecht estimates 

 the mean error of each of his polar co-ordinates a; and y at ± 0".02, 

 the results I found, justify the following two conclusions: 



1. the co-ordinates of the mean pole have remained unaltered 

 since 1904.0; 



2. the computed difference in phase of 9°. 4 is too slight to be 

 answered for, the more so, as a somewhat smaller value of P, ^) seems 

 not improbable. 



Therefore I accepted for both ])eriods : 



1) Cf. the last paragraph of this paper. 



