'5* 



IN STARRY REALMS. 



as often the same distance farther from the sun. The 

 orbit of this planet is thus farther out from the sun than 

 is that of our earth ; and in the annexed figure (Fig. 13) 

 we have drawn the relative sizes of the two orbits, both 

 represented in their actual form. It will thus be seen 

 how similarly the two bodies are circumstanced, in so far 

 as their relations with the sun are concerned. It is, how- 

 ever, obvious that the earth occupies a more favoured 



Fig. 13. Orbits of Earth and Mara. 



position for the enjoyment of the light and heat dispensed 

 from the common source. 



In another respect also the resemblance between this 

 planet and the earth is very notable. Our globe rotates 

 on its axis, and accomplishes each complete rotation in 

 one sidereal day ; that is, in 23 hrs. 56 min. 4 sec. of 

 solar time. In like manner does Mars revolve on it? 

 axis. By assiduous watching of the varied points on its 

 surface, which are seen gradually to turn round, to become 



