ASTRONOMY 117 



is inhabited by beings of a very high order of intelHgence. 

 Inasmuch as Mr. Lowell, the writer of these articles, will him- 

 self be in Columbia this winter, it hardly seems necessary for 

 me to enter into his arguments to any great extent. Most 

 astronomers are not at all in agreement with him as regards 

 the evidence on this point, their general feeling being that Mr, 

 Lowell has been somewhat carried away by the interest of his 

 hypothesis and by its importance, if true. Personally, I 

 hardly feel able to express an opinion that is worth much, but 

 I shall try to give the facts that bear on the case. 



In the first place, two questions are to be considered — 

 first, are the conditions on Mars favorable to the support 

 of life ? — second, are there any direct evidences that life 

 exists there ? 



In regard to the first question, three points need to be 

 considered : the character of the atmosphere of Mars, the 

 presence or absence of water, and its temperature. As 

 regards the atmosphere, the evidence seems to be rather 

 against the habitability of the planet, for the atmosphere 

 seems to be at most very thin. When this planet passes 

 between us and a distant star, the star vanishes suddenly as 

 the edge of the planet comes in line with it. If there were 

 much of an atmosphere, the refraction of light would cause 

 the star to change color and grow dim before vanishing. 



The evidence for or against the presence of water vapor 

 in its atmosphere is conflicting. Lowell and some others 

 maintain that they have good spectroscopic evidence that 

 water is there, while others, among whom are some of the 

 most able workers with the spectroscope, are equally sure 

 that there is no evidence for it at all. Around the poles of 

 the planet there are certainly some very white patches which 

 grow larger in winter and nearly disappear in summer, and 

 suggest snow. The opponents of Lowell, however, think that 

 these patches are really solidified carbon dioxide, which would 

 indicate a very low temperature. 



