1869.] 



Astronomy. 



93 



respects distance, as he possibly can be wben in opposition. But 

 on this very account be should be studied all the more carefully, as 

 the portion of his globe which will be turned towards the earth is 

 that which has been least studied, owing to the fact that it is never 

 presented towards us except when Mars is in or near aphelion. 



In Figs. 1 and 2 the presentation of Mars at the approaching 

 opposition is exhibited. The features are those presented in Proctor's 



E 



charts, which are derived from a series of drawings by the late l^fr. 

 Dawes. Many of the features of the northern hemisphere require, 

 however, to be carefully re-observed, since Mr. Dawes made his 

 observations on this hemisphere with an instrument considerably 

 inferior in 2)0wer to that which he made use of in observing the 

 southern hemisphere; and (as we have noticed) the northern hemi- 

 sphere is only turned towards us when Mars is in aphelion. "We 

 must also remark that it is not merely the question of presentation 

 which has to be considered. When Mars is presented towards us 

 as shown in Figs. 1 and 2, he is also presented in almost exactly 

 the same way towards the sun. Hence it follows that the northern 

 hemisphere is enjoying the martial summer; and accordingly the 

 martial skies are clearer over that hemisphere, and its features are 

 proportionately more distinct. This is no mere speculation respecting 

 the condition of the martial globe, but corresponds exactly with the 



