84 OUTLINES OF NATURAL PHILOSOPHY. 



SECT. IV, 



OF THE DISTURBANCES WHICH THE SATELLITES 

 OF JUPITER SUFFER FROM THE ACTION OF ONE 

 ANOTHER. 



THE application of the same principles to 

 the satellites of Jupiter, has fully explained all 

 the irregularities which had been observed in 

 their motions, and has reduced under known 

 laws several others, of which the existence had 

 been indistinctly perceived. 



A very remarkable relation takes place between the 

 mean motions of the first three satellites, as re- 

 marked 185; the mean motion of the first satel- 

 lite -f- twice that of the third, being equal to three 

 times the mean motion of the second, reckoning 

 from any instant of time. LA PLACE has shewn, 

 Mecanique Celeste, liv. n. chap. 8. that if the pri- 

 mitive mean motion of these satellites was near 

 this proportion, their mutual action on one ano- 

 ther must in time have brought about an accu- 

 rate conformity to it. 



It 



