89 
may for the greater part be accounted for by the influence which 
the accidental errors must have in the comparison of the zone- 
catalogues with KiistNrr’s, in consequence of the small difference 
of epoch. With regard to the possible systematic errors: 
a. errors due to magnitude-equations 
6. an error in the adopted motion of the equinox 
c. systematic errors in the fund. system dependent upon « and d 
on the other hand, the research here detailed is certainly not behind 
other determinations of the constants of precession from faint stars. 
As regards a, the errors due to magnitude have been eliminated 
in a very satisfactory way, undoubtedly better than has been possible 
in any other similar research, while the effect of the errors 6 and c 
does not depend upon the difference of epoch of the catalogues 
themselves. 
The question as to whether to the system V,, also adopted by 
Auwers, must be applied an appreciable correction of the form 
AE = AE, + AL T, 
in which A’ represents a correction to the centennial motion of 
the equinox, is discussed by Newcoms'). If a correction of this form is 
introduced, a corresponding one must be applied to the Ap from 
the A.R. namely: 
Corr. Ap =+ 1.09 AL’. 
Of the probable value of AZ' Newcoms makes an estimate. He 
comes to the conclusion that we may assume AL” — + 0"30. If we 
do that here also, our results become: 
Ap (R.A.) = + 0"44 + O'14; 
Ap (Decl.) = + 0.72 + 0.45, 
which values agree very satisfactorily with one another. 
In order that | might form some opinion upon the question in how 
far systematic errors depending upon «and in the p.m. of the New 
Fundamental Catalogue of Auwers could have exercised an influence 
upon the results, a comparison was made between the N. F. K. of 
Auwers and the Fund. Cat. of Newcoms. On the basis of the data 
occurring in the N. F. K. of the Berliner Jahrbuch?) a table was 
drawn up of the differences in u, and uw) (N. F. K.—Newcoms) for 
four groups of stars, corresponding in declination to the four zone- 
catalogues. Excluding a few very large differences | found as means: 
1) The Precessional Constant, p. 69 af. 
2) Veröffentlichungen des Königl. Astron. Rechen-Instituts No. 33, p. 100 et seq. 
