AND ITS VOLCANO. 413 



hill in their center, and are surrounded by a circular 

 ridge of a similar appearance. 



Query. May not the moon be surrounded by an 

 atmosphere of pure air, which differing essentially in 

 its properties from the atmosphere of our earth, might 

 account for some of the phenomena of her appearance 

 to us? An atmosphere of this sort might be so trans- 

 parent as not to refract the rays of light in a sensible 

 degree, or to produce the least change in the appear- 

 ance of a star passing through it when an occultation 

 is observed. At the same time, it w T ould increase in 

 a high degree, the inflammability and combustion of 

 matter, so as to produce volcanos; and if we suppose 

 the moon to have neither seas nor vegetation on her 

 surface, the sun's light would be more strongly reflec- 

 ted than from the earth, where the rays are liable tu 

 absorption by water and vegetables. 



Extract 



