of the Equinoxes. 
81 
fore the nutation caused by the action of the sun in a quarter 
of a year is 1" 27'" nearly. 
25. By the circular parts, radius xc = cot. LS x tang. BL 
= c, radius being 1. But x : \/ 1 — -xx : : 1 : — -f** — cot.LS; 
and therefore : ■ = tang. BL. Consequently by the last 
r I — XX J J 
, • 1 7 cx r- hbxx n 
and article 23, b : - - : : 300 x -x; x — — : 300 x 
V I— ^ 21 Z P 
■ xct h 
X “ X 
4T £ 
v'l- 
I — .T-T 
the fluxion of the precession when the sun is at S. 
Now the fluent of 
x 1 - x 
IS 
Z — I —XX 
For z 
V i — xx 
the fluxion of x V l—xxisx V 1 — xx — 
V 1 — xx 
x 2 x 
, and 
v 1 — 
Conse- 
1 — xx 
quently the whole fluxion of % — x s/ 1 — xx is 
s/ 1 XX -j- 
x x 
V l—X 
V i-~. 
v' i — 
XX 
+ 
V' i 
V ] 
+ 
x 
■XX 
V 1 . 
■ 2 * - Consequently the fluent of the precession, when the 
V I XX 
■ , o • /-> \ct b z — x V i —xx 
sun is at S, is 360 x xyx - 
When the sun arrives at the solstitial point C, then x be- 
comes equal to 1 , and z becomes equal to and the quantity 
of the precession is then 360 x x jx- = 360 x^tx~ 
This expressed in numbers, admitting the obliquity of the 
ecliptic to be 23 0 27' 43", is go x ^ x 77—7 x .917 3 8 * 3 in de- 
grees, and the same in seconds is 5400 xypy: x ^^77x55.042878, 
This calculation may be finished in the following manner. 
MDCCCVII. 
M 
