430 COSMOS. 



added afterwards when treating of the planets individually. By 

 the mean distance from the Sun, of which alone mention will 

 be made in this place, is to be understood the mean of the 

 greatest and smallest distance, or the half major axis of the 

 planet's orbit. It must also be observed, that the numerical 

 data employed, both previously and hereafter, are for the 

 most part taken from Hausen's careful classification of the 

 planetary elements in Schumacher's Jahrbuch for 1837. 

 Where the data refer to time, they are, in the case of the 

 older and larger planets, for the year 1800 ; but in the case 

 of Neptune, for the year 1851, by the aid of the Berlin Astro- 

 nomische Jahrbuch of 1853. The comparison of the small 

 planets occurring afterwards, and for which I am indebted to 

 Dr. Galle, refers exclusively to more recent epochs. 

 Distances of the Planets from the Sun. 



Mercury 0-38709 



Venus 0-72333 



Earth I'OOOOO 



Mars 1-52369 



Small Planets. 



