CATALOGUE OF POLAR STARS. 297 



Epoch. 



1855 

 1851 

 1843 

 1835 

 1827 

 1819 

 1815 

 1811 

 1803 

 1795 

 1787 

 1779 

 1775 

 1771 

 1763 

 1755 



In the choice of the interval tv, it will be safe to assume any value not exceed- 

 ing 15 when equations (64) and (66) are employed. When the interval does not 

 exceed ten years, the correspondence will in any case be exact for the interme- 

 diate dates. 



The following residuals, Tq — Y^, will indicate how far beyond the last value of 

 the series the correspondence with the exact values may continue. They were 

 computed from equations (66), using slightly different elements from tho.se thus far 

 employed, in which w = 10. The correspondence for sixty years was found to be 

 exact in every case. After this time, the assumed and the computed values were 

 found to be as follows : 



Epoch. 



1810 

 1805 

 1800 

 1795 

 1790 

 1785 

 1780 

 1775 



