WEIGHING THE WORLDS 



matter of tacit belief. It has become customary to 

 speak of our neighbors the Martians quite as if they; 

 had assured existence. Every one has heard, too, 

 of the canals of Mars, and most readers are prob- 

 ably familiar with the claim made by Professor Per- 

 cival Lowell that these canals can not possibly be 

 of natural origin but must represent the work of in- 

 telligent beings. Professor Lowell cites in proof of 

 the artificiality of these canals, their, straightness, 

 their uniform size, and their extreme tenuity; also the 

 dual character of some of them, and their relation to 

 certain spots which he interprets as oases; and in 

 general a systematic net-working by both canals and 

 spots of the whole surface of the planet. He believes 

 that these markings represent the vegetation about 

 actual canals that convey water (supplied by a melt- 

 ing ice-cap) from the polar regions and irrigate the 

 arid surface of the planet. 



Not merely the interpretation of these lines but 

 their existence has been challenged by various ob- 

 servers. The fine drawings of Mars made by Keeler 

 and Barnard with the 36-inch Lick telescope show 

 certain curious shadings and lines, but nothing 

 closely corresponding to Professor Lowell's pictures. 

 Nor does the photographic plate reveal anything 

 more than vaguely suggesting an intricate system 

 of canals. But it is conceded that these canals, if 

 they exist, lie almost at the limits of vision, and it 

 is probable that the question of their existence will 

 long remain a matter of controversy. Professor 

 Maunder, however, believes that he has settled the 

 question definitely, and it must be admitted that he 



8? 



