100 FROM NEBULA TO NEBULA 



self gives Mars a mean temperature of but 48 F., and 

 that only by construing every doubtful factor in his 

 favor. Other authorities who are not committed to his 

 theory think the temperature cannot exceed 32 F., that 

 is, our freezing point of water. The earth's mean tem- 

 perature is 60 F., yet our arctic regions remain one 

 perpetual snow. Now if the sun does not urn] cannot 

 do the work, what other effective agency remains but 

 water? And we can only explain how water does it by 

 supposing the polar snows to find merely a temporary 

 lodging place on the frozen surface of a sea, which sur- 

 face, as the summer advances, becomes overflowed by 

 warm tides from the tropics. A telling proof of this 

 reasoning is the diminutive summer cap worn by the 

 north pole; it is per in (incut because it rests on land,., the 

 inevitable implication being that the rest is sea. 



3. On a planet where warmth is surely as much of 

 a desideratum as water, we should expect to fond, settle- 

 ments only in the very wannest belts. The hyperso- 

 phisticated Martians, however, have nearly as tnany 

 canals and oases in the very heart of the arctics as in 

 the best favored regions, and, marvel of marvels, under- 

 neath the very snow-caps themselves! For proof, con- 

 sult Mr. Lowell's published maps. 



4. The canal mileage is about forty thousand. The 

 oases are rarely if ever closer to each other than 250 

 miles. Why this prodigality in length of canal, when, 

 as in another place Prof. Lowell points out, the Martian 

 engineers are so alive to the economy vested in great 

 arcs and straight lines? It is altogether likely that 

 some, perhaps many, isolated outposts would be found 

 necessary on Mars just the same as here, even under 

 their dire need for huddling together; but it taxes 

 sound reason to comprehend why there should be noth- 

 ing but outposts, why there should not be evidence of 



