i. Small craters near the hill-girt edge pt the Plain ot 

 Plato. These volcanic vents exhibit continuous changes, 

 and indicate lunar activity. Frequently obscured by 

 white clouds, they permit the escape of gaseous matter 

 trom below the moon's crust. From a model by Bolton 



Scriven, F.R.A.S. 2. The crater of Copernicus (No. 46 

 on previous page), scale i in. to 50 miles. 3. The lunar 

 Apennines, Archimedes (No. 56 on .previous page), etc., 

 scale i in. to 60 miles. 2 and 3 from The Moon, J. Nas- 

 myth and J. Carpenter, by courtesy of John Murray 



MOON: PHOTOGRAPHS OF MODELS OF CRATERS CONSTRUCTED FROM TELESCOPIC 



OBSERVATION 



