Precession Cindy utalion of Fixed Slavs. - 217 



14' 2", the correct difference of altitude resiiltino- from obser- 

 vations at five different stations, 614 feet. The true ano-ular 

 difference is consequently 2' 36"; the refraction at Ino-tebo- 

 rough ^t. ; and at Great Whei-nside y^- '^ 



X. X. 



[To be continued.] 



XLVII. Supplemenlary Table for computing the Precession 

 and ISutation of the Fixed Stars. Bj/ F. Baily, Esq. F.R S 

 and L.S. 



To the Editors of the Philosophical Magazine and Journal. 



TN your Magazine for October last, I alluded to some new 

 tables of Aberration and Nutation which had been com- 

 puted under the direction of M. Schumacher, and inserted by 

 him in his Astronomische Hiilfstafeln for 1822. Tables for 

 the computation of those quantities are of constant use to the 

 practical astronomer : but, it must be evident, to those who are 

 acquainted with the principles on which M. Schumacher's 

 tables are constructed, that the values denominated A and B 

 (which are confined to the Precession and Nutation) require 

 to be calculated evcri/ year. M. Schumacher, however, has 

 given them only for the years 1819-1822; which renders the 

 general tables, to which they refer, of little or no use at the 

 present time. 



In order to remedy this temporary defect, I have computed 

 (for my own use) the logarithms of A and B for the years 

 1823 and 1824: and as they may probably be of service to 

 some of your readers, and perhaps render the adoption of 

 M. Schumacher's tables more general, I have sent them for 

 nisertion in your Magazine. I should remark that, in the 

 value of B, I have included the quantity denoted by + -08768 

 cos 2 9, , in order that the total result may accord with those 

 deduced from the rigorous formula given by M. Bessel. 

 I am, gentlemen, 



Youi- obedient servant, 

 March 19, 1823. Fkancis Baily. 



Vol. 61. No. 299. March 1823. Ee Day. 



