126 THE PLANET MARS : IS IT INHABITED ? 



replies that no theory about water and its reflection of light can 

 explain them. Professor Pickering's polarising experiments on the 

 light from these blue-green areas, made some years ago, and 

 repeated along with Mr, Lowell, also ended in the same verdict. 

 The only thinkable alternative, therefore, is that the colour-changes 

 are caused by the seasonal development of vegetation from green 

 through bloom to the " sere and yellow leaf" of decay. It need 

 scarcely be added that the lines which the telescopist sees, are not 

 the " canals " or water-courses, but the fringes of vegetation bor- 

 dering the " canal," and extending for some eight to twenty-five 

 miles on each side. As regards the general order in degree ot 

 visibility, it is noticed that the first areas, lines, and oases to become 

 deeper in tint, are those nearest the polar snows ; those near to 

 the Equator being the last (except those running east and west) to 

 receive the benefit from the Martian annual freshet. 



The question will occur here to many minds : — Like as Earth 

 contains, in addition to springs, reservoirs of fresh water every- 

 where near to its surface, and which are available for human con- 

 sumption, may we not suppose that on Mars, a planet so analogous 

 in many respects to Earth, a similar provision may exist for the 

 necessities of its supposed inhabitants ? From the fact that Mars 

 is a much smaller planet (in volume 15, in mass 11, in density 72, 

 in diameter 53, and in surface 28, each against Earth's 100), and 

 therefore having cooled much more rapidly than Earth, we may 

 reasonably conjecture that near its surface it is more extensively 

 honeycombed ; and therefore that its reservoirs of rain-water are 

 proportionately more numerous. Against this theory we have the 

 fact that Mars, as an inhabitable planet, must be enormously older 

 than Earth, and therefore that its initial stores of water may have 

 drained too deeply inwards to be accessible. In the supposition, 

 also, of an ever-increasing drought during thousands of years in 

 the past, it is open to us to conceive that the inhabitants may 

 have been drawing, largely and continuously, upon these internal 

 stores of the precious fluid. 



The entire evidence, including that from analogy and contin- 

 uity, thus goes to show that we are here dealing with a world 

 substantially like our own in origin, history, elementary compo- 

 sition, and structure, but much older than Earth, and therefore 



