ASTRONOMY. 169 



Astronomiques, p. 585. LA LANDE has simplified 

 the demonstration, J 1188. See also BJOT, vol. HI. 

 p. 181., Note. 



b. If, by help of the above formula, we inquire, sup- 

 posing the Earth to revolve in a year round the 

 Sun, and Mars in 686.98 days, what must be the 

 ratio of the distance of the Earth to the distance 

 of Mars from the Sun, in order that the latter 

 may be stationary at the elongation of 136 Q ? we 

 shall find it to be that of 1 to 1.52, which is the 

 ratio deduced from other phenomena. 



c. Not only are the stations thus explained, but the 

 extent of the arches of progression and retrogra- 

 dation also. This coincidence affords a strong 

 presumption in favour of the system of the Earth's 

 motion, or that which, from the name of its dis- 

 coverer, is called the Copernican System. 



d. The same holds of Jupiter, Saturn, Uranus. The 

 same motion of the Earth, and the same distance 

 from the Sun, will account for the phenomena in 

 all the cases ; so that whatever probability there is, 

 from the phenomena of one planet, in favour of the 

 Earth's motion, the same is increased in a quadru- 

 plicate ratio, from considering the phenomena of 

 all these four superior planets. 



e. The two inferior planets, give a similar increase of 

 evidence. The four new planets are not taken 



into 



