282 METEORS AND AEROLITES. 



offers the aspect of mountains of great height, and of 

 numerous craters; the latter resembling very exactly in 

 character those of our own volcanoes, but much more spacious 

 and profound.* That internal forces exist, or have existed, 

 within this satellite, capable of powerfully disrupting, ele- 

 vating, and projecting from its surface, must be deemed 

 certain in fact, notwithstanding that all astronomical obser- 

 vation goes to disprove the existence of a lunar atmosphere 

 or lunar seas. Why not suppose stones to be projected thence 

 (no atmospheric pressure existing to retard or arrest them) 

 with force enough to depass the limits of the Moon's attrac- 

 tion, and to come within that of the earth ? The calculations 

 just referred to concur in the result, that an initial velocity 

 five or* six times as great as that of a ball issuing from the 

 cannon's mouth, might carry a stone so far that it would not 

 return to the Moon ; but either continue to revolve subor- 

 dinately to new attractions, or be precipitated upon a body 

 of more powerful attraction if approaching its sphere. 

 Berzelius went farther in his adoption of the lunar hypo- 

 thesis ; and, looking to the chemical composition of aerolites, 

 ingeniously conjectured that an excess of iron on one side of 

 the Moon might fairly account for the fact of this side 

 being constantly opposed to the magnetic globe of the 

 earth. 



* The great works of Schrotter, and Beer and Madler, on the Moon, are 

 well known to our astronomical readers. Not equally known are the curious 

 researches of Mr. Nasmyth, of Manchester, on a certain definite portion of the 

 Moon's surface, about as large as Ireland, named in lunar topography Moro- 

 lychus. Several years of constant observation given to that one region (a 

 limitation of object generally fertile of results) have enabled this diligent 

 observer to construct a model and maps on a large scale, well illustrating the 

 volcanic character of the Moon's surface, and the vast changes by disruption 

 and elevation which have occurred there. 



Mr. De la Rue's admirable application of Photography to the mapping of the 

 Moon, under appliances which only his skill could suggest, furnishes a new 

 mode of astronomical observation, already brought into other use in the phe- 

 nomenon of solar eclipses, and capable of further extension. 



