691 



For Newcomb's result from (lie BRADi.KY-stai'S we find, taking 



Z 



according to Newcomb — =^-\-V%Q: 



Ln=[Lii\ — 0".00 -h 0".02 — 0".18 = [Ln\ — O'Ml 

 so that 



corr. d/> Newc. = — 0".29. 



As tlie first correction term is always small and the three othei-s 

 have as taclor cos'' d .sm 6, while the sum — 0.20 0.04 



Rm R,n 



Z 

 — 0.43 — has a consideralile negative value, the precessional 



constant from dcclinnfions will lie found too /ajy^ for stars witli a 

 north decimation, or when in the compared catalogues stars with 

 a north declination ai'c preponderant, while stars with a south 

 declination will yield too small a value. 



We have therefore arrived at the remarkable result that, in derixing 

 the precessional constant in the ordinary way, in which no attention 

 is |iaid to the dependence of the distances upon the galactic latitude, 

 from catalogues with preponderating north declinations the lunisolar 

 precession /> is found larger from the declinations than from the 

 R.A., while the true value must lie between these two, and nearer 

 to the result from the R.A., and thus, to some extent at least, the 

 discrepancy found by Newcomb is accounted for. The values finally 

 assumed by Newcomb for (^) and those corrected accoi'ding to our 

 investigation are as follows: 



Newcomb Corrected 



rfy* from R.A. + 0".36 + 0".48 



„ Decl. + 1 .12 + .83 



The difference found by Newcomb is thus reduced to half, and 

 no longer presents a serious difficulty. 



It should be mentioned once more, that, after the completion of 

 our calculations, the explanation found here appeared to have 

 been suggested by Newcomb himself as a possible cause of the discre- 

 pancy; so far his remarks upon this subject do not appear to have 

 received sulïicient attention. 



Distinguishing by the names of "vernal region" and "autumnal 

 region" the regions between R.A. 19'^. 5 and b^.b and between 

 7''. 5 and 17''. 5, he says on p. 67: "A very little consideration 

 "will show that if the stars of a given apparent magnitude are 

 ''farther away within the vernal region than within the autumnal 



