328 



Astronomy. [Lecture 20. 



The secondary planets, like the primary, finish 

 their revolutions in longer times, in proportion 

 as they are further from the centre of their orbits, 

 the relation of the square of the times, and the 

 cubes of the mean distances obtaining equally 

 with all, as may be seen by the following table. 



TABLE of the duration of the periodical revolu- 

 tions of the secondary planets round the prin- 

 cipal planet. 



XT c ,, , Duration of the Revolutions. 



Names of the Planets. / doyg hrs< ?* , InSeconds . 



