THE PLANETS MARS AND VENUS 351 



ness of summer than by the asperity of winter. Mars' 

 mean temperature he estimates at about 48 F. 



8. Unlike the snow caps of our Arctic and Antarctic 

 regions, those of Mars are not permanent, but disappear 

 all but totally every recurring summer season, and are 

 redepo sited during the succeeding winter with the same 

 unfailing regularity. Reminding us of the fact that the 

 solar warmth is only 4-9 as great as here, Doctor Lowell 

 argues from these two premises combined that the polar 

 snow deposits must be very scant indeed to be so easily 

 and quickly dispersed. 



9. Philosophically speaking, the evolution of life 

 from matter is the order of Nature. Mars, whether or 

 not older than our planet, presumably cooled earlier, both 

 because smaller in size and more remote from the sun. 

 Hence it has already run the gamut of evolution, and, 

 by the principle of survival of the fittest, the present 

 Martians must be the highest products of their race. 

 Historically, they have witnessed the birth of a world 

 and seen it pass through its seven ages into that of the 

 sere and yellow leaf. Even the seas have dried up, part- 

 ly by absorption into the interior and partly by the 

 escape of the molecules into the outer air. The race is 

 at bay, being driven slowly, but none the less inevitably, 

 to extermination by the road of thirst ; for the snow-caps 

 must be thinning year by year, and eventually must al- 

 together vanish never to reappear. 



Criticism of Lowell's Theory 



As a scientist, Doctor Lowell was an excellent fic- 

 tionist. Becoming early enamored of his pet idea, he pur- 

 sued it relentlessly, in season and out of season, twist- 

 ing the most intractable of facts to suit his preconcep- 

 tions; reasoning not to a conclusion, but to support a 

 conclusion previously irrevocably resolved upon. Let 

 us scan his arguments dispassionately with the view of 

 allowing ourselves to be guided by the plain facts rather 

 than by predilection. 



