BOOK OF NATURE LAID OPEN. 189 



rowed or reflected light of the sun, and her face, in- 

 stead of being too dazzling to behold, presents, like 

 the earth, a dark unequal surface, pleasantly diver- 

 sified with hills and vallies, mountains and cavities. 

 Seas and lakes have also been exhibited as adorning 

 this body, by the constructors of some maps of the 

 moon ; but the powerful glasses of Dr. Herschel are 

 said to have dissipated such delusions; and, as it 

 appears from the clearness of her disk, and the cir- 

 cumstance that, when any star approaches her, it 

 retains its lustre till it touches the very edge, and then 

 vanishes in an instant; that the moon has no at- 

 mosphere, there is the less probability that there are 

 lakes and seas, from which clouds and other atmo- 

 spheric phenomena are formed. 



The Phases of the Moon, 



And the circumstance of her having always the same 

 face turned to us, are very rationally accounted for 

 as follows. The moon is known to have a twofold 

 motion ; the one she performs round the earth in the 

 time of a lunar month, and the other she performs 

 round her own axis in exactly the same period. By 

 the latter motion, she naturally behoves to turn al- 

 ways the same face to the earth ; and, by the former, 

 her various phases are produced. When that part 

 of the moon which is illuminated by the sun, is turn- 

 ed wholly towards the earth, we then see one of her 

 sides, round and fully enlightened, and in that situ- 

 ation we say w&have a full moon; when the side 



