PLATE XV. 



CENTRAL PORTION OF THE MOON FROM THE M. SERENITATIS TO ST6FLER. 

 BY M. HENRY, PARIS OBSERVATORY. 



All the more important structures shown in this plate have been displayed in the preceding 

 plates under different conditions of illumination. The most noteworthy features here illustrated 

 are the seas. The lowest or northernmost is the southern part of the M. Serenitatis, which will be 

 seen to have its surface apparently somewhat lower than the adjacent M. Tranquilitatis. This 

 latter passes on the left hand or western side into the M. Fcecunditatis, which is shown only in 

 small part, and on the south into the M. Nectaris. At the southern end of the M. Nectaris is the 

 great vulcanoid Fracastorius with its northern wall broken down apparently by the melting action 

 of the lava of the mare. 



South of the distinct crater of Menelaus, a little to the right of the uppermost part of M. Se- 

 renitatis, at about one-fifth the distance from the bottom of the plate towards the top, is a very 

 irregular vulcanoid, Julius Caesar, which is partly broken down by the neighboring mare. Touching 

 the northern or lower margin of Julius Caesar is a good example of a crater valley. Several others 

 are included in this plate. About half the width of Julius Caesar farther to the south is the 

 Ariadaeus cleft, one of the straightest fissures on the moon. 



On the most illuminated part of this plate the bright streaks begin to be traceable ; they are 

 most visible on the M. Nectaris. 



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