[ 437 ] 
ceding Problem , inftead of a , 1 ~ x 180 degrees) f x 
22 
X -^Zj_ x x 7 x , 3o degreeS) = 
(365^) 2x176 IOOOOOOO 22 D 
(after reduction) 10'". 19"". 
Problem XVI. 
4,0. To find the motion of the node of Jupiter** fourth 
fate llite, caufed by the fun , during the time of \ of a 
revolution of that fatellite about the fun . 
We need only make ufe of the formula of Pro- 
blem XI. wherein, conformably to Art. 25. we muft 
make — 1 , t = 1 6? days, being the time of 
1 — 2 a 
the revolution of the fatellite about Jupiter ; T — 
x 12 days, which is the time of the fatellite’s 
y 
revolution about the fun, or about 12 years; 
r 
becaufe the orbit of the fatellite is but little inclined 
to the ecliptic, and, confequently, the axe thereof 
nearly at right angles thereto. 
We fhall have then ^x 
1 o 
or 
3 x 164 180 deg. 
365^ x 12 8 
This is the motion of the node of this fatellite in 
3 years, or during 4 of its revolution about the fun. 
Remark. 
41. By this may be found the motion of the nodes 
of the reft of Jupiter's fatellites. For it appears, 
from the formula , that the motion of the nodes of 
different 
