the effects oj parallax, &c. of certain fixed stars. 
347 
Number of 
Observations 
in 1803 - 1814 . 
Number of 
Observations 
in 181 S- 18 - 20 . 
Equations deduced. 
Greatest coeff. 
of Nutation of 
Ob. Eclip. 
Capella 
3 ° 
96 
54,20 + 8,493=53,50 — 7,793 
II 
9,09 
£ Tauri 
18 
84 
21,73 + 8,663/2=21,65 — 7,633/ 
9+5 
a Orionis 
18 
148 
9,24+8,813= 7,98—7,09 3 
8,75 
Castor 
IO 
66 
30,23 + 8,923 = 30,42 — 5,183 
9,62 
Procyon 
l 6 
136 
8,41+8,913= 7,30 — 4,883 
8,74 
Pollux 
IO 
6 S 
44,98 + 8,793=44,29 — 4,813 
9 >° l 
y Draconis 
27 
132 
7,54—8,653= 7,90 + 5,803 
9,26 
as Lyras 
126 
155 
42,69 — 9,143=42,94 + 7,893 
9 > 3 6 
as Aquilas 
76 
238 
4,94—8,743= 5,10 + 7,423 
9 , 4 ° 
as Cygni 
47 
I 20 
42,15 — 7,483=42,77 + 4,973 
9 ,0 3 
378 
I 24O 
9+5 
On account of the small number of observations of some 
of the stars at the first period, it appears better to take the 
mean, by giving each result a weight proportional to the 
number of observations of each star at the first period. The 
mean result so obtained is 9'', 25. With this result (omitting 
the small terms depending on 2 long, a ) 
The nutation in N. P. D. = — 8 ", 06 sin ( Jt— Q) — • i", 19 sin (jit -{- & ) 
The nutation in JR = ( — 8,06 cos ( 7 R — a) — 1", 19 cos ( 7 R+ a )) cot. N. P. D. 
Equation of equinoxes in At = — 15", 86 sin a 
Equation of equinoxes in long. 1= — 1 7^,29 sin a 
Equation of obliquity ecliptic = cos £3 
With the above nutation, the mass of the moon = ~, that 
of the earth being unity ; and the force of the moon on the 
sea = that of the sun being unity. 
Had the former observations for each star been as nu- 
merous as those in the latter, it cannot I think be doubted, 
that the discordances of the results would have been less. 
The discordance between the greatest and least result is less 
than one second. Hence it might perhaps be inferred, that, 
mdcccxxi. Y v 
