The Lunar Arctic Region — Occultations. 57 



drawings that we shall be able to ascertain whether any 

 enlargement of existing craters is in progress at the present 

 day. The extensive system of measurement which Mr. Birt 

 has undertaken with so much spirit and energy will be most 

 valuable in this respect. 



It is not our intention to enter into speculations as to the 

 origin of the present condition of the lunar surface; some 

 inferences are, indeed, very obvious ; still, on the whole 

 sufficient materials have not been collected for any satisfactory 

 generalization. But suggestions are always admissible, and 

 sometimes useful ; and it may therefore be remarked that the 

 aspect of the partially-doubled and divergent rampart of 

 Posidonius might be thought indicative of the intrusion of 

 semi-fluid matter from beneath into a combination of two 

 craters, one formed excentrically within the other. 



OCCULTATIONS. 



February 2nd. — a- Arietis, 6 mag., llh. 57m. to 12h. 

 46m.— 9th,. 60 Cancri, 6 mag., 5h. 16m. to 6h. 16m. 



