959 



bright: Am = — l"2i 

 faint : hin = — 1"26 



per century. 



per century. 



In order to investigate this point further I divided the material 

 into three groups according to the magnitude. Again no influence 

 of the magnitude upon Am was perceptible. We are there/ore 

 iustified in drawim/ the important conclusion that in all probability 

 Bessel's magnitude error loas very small. 



The above values Lni are corrections to the values of Struve- 

 Peters; reducing to Newcomb we find as the mean : 



Lm Newcomb = — 0"72 per century. 



b. 'From the Declinations. Here, also, the agreement between the 

 solutions is satisfactory; the general mean is: 



Ln (Struve-Peters) = — 0"80 

 Ln (Newcomb) = — 0"27 



To deduce a value for the precession correction from R. A. and 

 Decl. together, it is simplest to calculate the correction hp for the 

 lunisolar precession both from A???, and hn. As corrections of 

 Newcomb's values I found : 



Ap (from Lm) = — 0"1S 

 Lp (from hn) = — 0"68 



or, if we introduce another correction to the value of Ap from 

 the R. A. on account of the correction of the motion of the equinox 

 iVi which Newcomb ^) considered to be probable : 



hp (from Am) = — 0"45 

 Ap (from An) =— 0"68 



which are in good agreement. If these values are combined with 

 the weights 2 and 1, the result becomes : 



Ap=r — 0"53. 



A reduction of the results to the Fundamental Systems of Newcomb 

 and of Boss gave practically agreeing values. Finally I assumed as the 

 final result of this investigation : 



Ap = — 0"54 ; Am = — 0"50 ; An = — 0''22. 



In the first part of my investigation containing the comparison of 

 Kü — Zone-Catalogues of the A. G. the following results were 



^) Precessional constant, p. 69 sqq 



67^ 



