[ 43 $ ] 
inftead of a t — 
7 r 
dir 
21 
7 7 
— 7T = - — x 180 deg. 
22 22 ° 
7 
(fince a 7r is the femi- circumference of the circle 
wherein this inclination is performed) we (hall 
have J_ x — — x -Mill! x L x ,8o deg. 
365 j 4x176 iooooooo 22 
= (after redu&ion) 57"'. ay"". 
Problem XV. 
39. To find, the difference of the inclination of the 
earth's axe to the plane of the lunar orbit , when the 
moon arrives at its point of fiation , 90 degrees difiant 
Jrom the node of the equator with the lunar orbit , this 
difference of inclination being caujed by the moon . 
By Art. 18. the variation of inclination will be 
„ M 
-\B x x a a. 
a 2 vr 
Putting, inftead of B, its value of Art. 30.; in- 
inftead of M> which expreftfes the time of the 
moon’s revolution about the earth, 27 -days; in- 
, , , 398215-5 T r 
{lead of the mean value — ; I fay mean 
r iooooooo J 
value , becaufe the earth’s axe is not always equally 
inclined to the plane of the lunar orbit, as has been 
3 X £ 
jfhewn in Art. 19. &c. we (hall have y x x 
(3 
»7l 
2 X 176 IOOOOOOO 
(putting, as in the pre- 
ceding 
