5 68 THE POPULAR SCIENCE MONTHLY. 



desert in 120 20' east longitude. No water-courses were found flow- 

 ing to the eastward ; along the twenty-fourth parallel to 127 east 

 longitude, the country was found to be an open desert. 



" This very imperfect survey of the geographical work of the world, 

 when regarded as the work of a single year, justifies, I think, what 

 I said in ray last address that we are living in a great geographical 

 age." 







IS THE MOON A DEAD PLANET? 1 



IT is not a little curious that the great body which for ages has been 

 proverbial for its changeableness should have at last come to be 

 looked upon as the most unchangeable of bodies. When the earth 

 was regarded as constituting the universe, and the heavenly bodies 

 as mere exhalations from it, the moon was, of course, believed to be 

 nothing but a meteor a great lantern hung in the sky to illuminate 

 and rule the terrestrial night ; but, when modern astronomy had 

 established the idea that the earth is but a moving planet, and the 

 planets themselves great orbs like our own globe, speculation inevita- 

 bly arose in regard to their condition. It was then concluded that 

 the moon may be like the earth, with its oceans, plains, mountains, 

 atmosphere, vegetation, and inhabitants ; and this idea long prevailed 

 as a part of the great doctrine of the plurality of worlds. But an 

 opposite opinion at length grew up among astronomers, wdiich has 

 been greatly strengthened in recent years. This change of view has 

 been largely ascribed to the celebrated astronomer Madler, who made 

 a very forcible statement of the differences and contrasts between the 

 condition of the moon and that of the earth, and pointed out that the 

 current view that the moon may be a copy of the earth is impossible. 

 These views crept into astronomical text-books, and gradually led to 

 the conviction that the moon is a sort of played-out or defunct planet, 

 destitute of air and life a mere mass of rocks and cinders, cold, life- 

 less, and unchangeable. 



But although this view is still current among astronomers in gen- 

 eral, there is a class of astronomers (selenographers, as they are called) 

 who have studied the lunar surface with long and profound attention, 

 and to whom we are indebted for our present knowledge of our satel- 

 lite, who hold a different view. They agree in the belief that many 

 processes of actual lunar change are in progress, and they have de- 

 tected the existence of a lunar atmosphere. This conflict of opinion 

 is said to be due to the fact that the labors of selenographers are in- 



1 Abridged from an article in the Quarterly Journal of Science, entitled "Physical 

 Changes upon the Surface of the Moon," by Edmund Neisan, F. R. A. S., author of 

 " The Moon, and the Condition and Configuration of its Surface." 



