128 



Proceedings of the Royal Irish Academy. 



Date. 



Eefr. 



Eed. 



Sum. 



A5. 



1871. 













Septembei 



13, 



+ 0"-018 



- 0"-028 



- o"-oio 



62"- 



789 



jj 



21, 



+ -018 



- -022 



- -004 



62 • 



809 



j> 



23, 



+ -018 



- -021 



- -003 



62 • 



600 



j; 



28, 



+ -018 



-0 -018 



- -000 



62 



779 



October 



7, 



+ -020 



-0 -012 



+ -008 



62 • 



918 



>> 



20. 



+ -019 



- -005 



+ -014 



62 



908 



>j 



21, 



+ -022 



- -004 



+ -018 



63 



008 



j> 



24, 



+ -020 



- -002 



+ -018 



62 



918 



November 



5. 



+ -023 



+ -005 



+ -028 



62 



949 



n 



22, 



+ -018 



+ -013 



+ -031 



62 



858 



December 



16, 



+ -018 



+ -020 



+ -038 



62 



945 



5> 



19, 



+ -019 



+ -021 



+ -040 



62 



973 



?J 



20, 



+ -018 



+ -021 



+ -039 



62 



755 



1872. 















Jamiary 



6, 



+ -023 



-f -021 



+ -044 



62 



811 



March 



1, 



+ -025 



+ -005 



+ -030 



63 



257 



>> 



8, 



+ -023 



+ -002 



+ -025 



63 



096 



jj 



14, 



+ -024 



- -001 



+ -023 



63 



149 



?> 



17, 



+ -022 



- -004 



+ -018 



63 



098 



April 



3, 



+ -018 



-0 -012 



+ -006 



63 



040 



5> 



12, 



+ -018 



-0 -016 



+ -002 



63 



079 



>> 



13, 



+ -018 



-0 -017 



■r -001 



63 



012 



May 



31, 



+ -018 



- -030 



-0 -012 



62 



992 



June 



5, 



+ -018 



-0 -030 



- -012 



62 



931 



j> 



7, 



+ -018 



- -030 



- -012 



62 



954 



July- 



14, 



-fO -018 



- -023 



- -005 



62 



•801 



August 



2 



+ -018 



- -015 



+ -003 



62 



•899 



?> 



e! 



+ -018 



- -014 



+ -004 



62 -895 



If we take then ASo as a mean value of AS, d\' as the difference 

 of the proper motions of the star and nebula, and denote the difference 

 of the parallax of the nebula from that of the star by tt, that of the 

 constants of aberration for the two objects by k every observation 

 will give us an equation of the form : 



= A8o-AS + (^. ASo + !;. f/A'-J.i2. cos {® -\-£). Tr-b. sin (0 + ^). k. 



The values of the constant quantities B and b were found from the 

 well-known formulae 



^ = 270°- 19', 



b = 1-0000. 



the latter value being equal to unitv, because the nebula is close to 

 the Is'orth Pole of the Ecliptic. 



