THE TEMPERATURE OF MARS 



By PHILIP H. LING, M.Sc, Brist., B.Sc, Lond. 



It is only comparatively recently that it has been found possible 

 to examine, with any approach to scientific method, the question 

 of the habitability of the planets. The ingenious theories of 

 Prof. Lowell have drawn attention to the possibilities pre- 

 sented by Mars, and though the problem is still far from 

 being settled, considerable advance has been made. 



In discussing the question we have, of course, to limit our 

 inquiries entirely to life as we know it. Thus the planets 

 Jupiter, Saturn, Uranus, and Neptune appear to be in a semi- 

 molten state, which quite precludes any possibility of their 

 being inhabited. In fact, Mars and Venus seem to be the only 

 planets which are not ruled out by some unfavourable physical 

 condition, though the suggestion has been made that the 

 satellites of Jupiter may receive sufficient heat from their 

 primary to render some of them habitable. 



Now the problem can be definitely solved only by the 

 appearance of some phenomenon which can be due to no 

 conceivable cause other than living intelligent beings. This 

 is what Prof. Lowell claims to have discovered in the case 

 of Mars. But while in view of the extreme diversity of opinion 

 concerning them in the astronomical world his theories cannot 

 be considered decisive, they may be supported or opposed 

 by a different type of argument. Such is supplied by an 

 examination of the physical conditions on the surface of Mars. 

 Unfortunately there is, even here, very considerable difference 

 of opinion. It is clear that the non-existence of oxygen in the 

 Martian atmosphere, if proved, would settle the matter at once ; 

 and the same would occur if the temperature were not some- 

 where in the neighbourhood of that prevailing on the earth. 



But the question of temperature is even more intimately 

 connected with the subject. Prof. Lowell's " canal " theory 

 depends essentially on the idea that water is conveyed by 



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