THE PLANETS MARS AND VENUS 347 



attain a breadth in some places of 300 or 400 miles, and 

 are then found to be of a dark blue color. The polari- 

 scope shows that, unlike the rest of Mars, their surfaces 

 are shiny. The yellow regions are thought to be deserts. 

 They cover more than half the entire surface. Very 

 marked changes sometimes appear in the finer details 

 when the snow is melting most rapidly. At the approach 

 of the Martian autumn those parts of the dark areas that 

 are near the poles are seen to fade out and turn yellow 

 so as to be indistinguishable from the planet's soil". 



Lo WELI/S THEORY OF AN INHABITED MARS 



Doctor Lowell had long been a close student of Mars 

 and a prolific writer on this his favorite theme, when, in 

 1909, he published his Mars as the Abode of Life, in which 

 he summarized the whole subject. As basic facts, be- 

 sides those enumerated above, for his theory, he cites 

 the following (I quote his exact words only in part) : 



1. "The northern snow-cap diminishes from 78 to 

 6, the southern dwindles from 96 to nothing. 



2. "Mars' surface is singularly devoid of ir- 

 regularities. The more minutely it is viewed the more 

 its levelness grows apparent. Calculation shows that 

 heights even of very moderate elevation should be visible 

 if such existed and none show. 



3. "Excluding the polar caps, the surface consists 

 of large robin 's-egg-blue patches indiscriminately placed 

 upon a general background of rose ochre, the relative 

 areas being %ths to %ths. The tints frequently vary in 

 shade and grade off insensibly into each other, thus mak- 

 ing regions of intermediate color but the precise borders 

 of which are not decipherable by the eye". The ochre 

 regions he construes to be deserts of sand and rock in- 

 trinsically of that color. "White dots too are scattered 

 over the disk, dazzling diamond points that deck the 

 planet's features to a richness beyond the power of pen- 



