C 43 ] 
It may be obferved, that this method is equally 
applicable, whether the axis of Jupiter is perpendi- 
cular to his orbit, or not ; for if it is not, we can 
eafily find by propofition I and II. the fpecies and 
pofition of that elliptic fedtion of Jupiter’s body, to 
which a right line conne&ing the centers of the fun 
and Jupiter is perpendicular ; and this being obtained 
every thing elfe will remain as before. 
As it would require more time, than I have to fpare 
at prefent, to enter into a particular inquiry concerning 
the alterations, which this irregularity in the fhadow 
will occafion, in the prefent theory of Jupiter’s fatel- 
lites, I (hall conclude with obferving, that the errors 
in the femi-durations of their ecliples, arifing from 
this caufe, may fometimes amount to 20 // in the 
firft; 50" in the fecond ; 1' 19" in the third ; and 
n 7 14" in the fourth; which errors will, I believe, 
be deemed fufficiently large to merit the attention of 
aftronomers. 
G. Witchell. 
IV. An 
