Lessen XL] THK MOON. 49 



than any of the former astronomers : he has de- 

 termined that very few of them exceed half a mile 

 iu their perpendicular elevation. He has also ob- 

 served several volcanoes on the Moon, emitting 

 fire, as those on the Earth do : and indeed there 

 seems no reason to doubt, that, to complete the 

 similarity between her and the Earth, she has also 

 seas, rivers, and an atmosphere. 



Christianas Huygens, in his excellent Conjec- 

 tures concerning the Planetary World, says, " Tis 

 " certain that the Moon has no atmosphere sur- 

 " rounding her." He then proceeds to give his 

 reasons for such an assertion. But he has in this 

 instance fallen far short of his usual sagacity j for 

 the existence of a lunar atmosphere has been fre- 

 quently proved, by later writers, from the most 

 manifest considerations. 



If the Moon shone by a light of her own, we 

 should feel a sensible warmth from her rays : but 

 it is a light reflected from the Sun with which she 

 shines, and is so exceedingly weak and languid, 

 that the most powerful burning glass will not collect 

 enough to make any sensible degree of heat. This 

 has been accounted for j and those who have gone 

 through the computation assert, that the light of 

 the full Moon is ninety thousand times less than 

 day-light. How wonderfully is infinite goodness 

 and wisdom displayed in this instance ! For if the 

 Moon's reflected rays produced heat, as the air of 

 the night would then have a continual warmth, it 

 is obvious that it would be prejudicial to the health 

 of mankind. 



The 



