68 
Dr . Brinkley on the 
Hence this Table 
Observed 
Difference of 
Declination. 
Variation in 
10 Years. 
At 
Reduced to ! 
1780. | 
1 
l 7 z 7 
1 75 5 
1774 
1800 
1823 
Dr. Bradley, Wanstead. 
Dr. Bradley, Greenwich. 
Dr. Maskelyne, Schehallien. 
M. Piazzi, Palermo. 
Dr. Brinkley, Dublin. 
? n 
+ 10 38,4 
— 7 59>3 
— 20 38,4 
—37 54 > 6 
—53 n>o 
/ // 
6 39,2 
6 39 >S 
6 38,6 
6 38,4 
1741 
1764 
1787 
1812 
' " i 
6 39,0 
6 39>4 
6 38,6 
6 3 8 >5 
The last column is deduced from the fourth, by computing 
from* the secular variation of annual precession in diff. decl. 
Table III. = + o" ,067 — o",o29 = -f o",o38. 
The mean of the last column is 6 ' 38", 9, the same as that 
deduced by comparing the Greenwich observations of 1755, 
with the Dublin of 1813. 
The variations in the last column agree so nearly, that 
there cannot be a doubt that the apparent motions of decli- 
nation of these stars have been uniform for upwards of 
ninety years. 
(II.) The observations made in France with a sector, in 
1739 and 1740,-f appear to have been exact, by comparing 
the amplitudes of the same arc determined by different 
stars. 
The lunar nutation was then unknown ; but if we correct 
the observations for this, and solar nutation, we may then 
deduce the differences of declination of certain stars, and 
compare them with later observations. 
According to Mr. Pond, Capella has a considerable south- 
* The secular variation is here and elsewhere given retrospective, 
t La Merid. Verif. p. Ixxxiii., &c. 
