MARKINGS OF MERCURY ANTONIADI 105 



the atmosphere of that world. Meantime the low albedo of these 

 clouds, which does not exceed 0.2, is quite different from that of our 

 cumuli at 0.7, so that the only admissible explanation of the atmos- 

 pheric veils of Mercury is that they are probably due to minute 

 particles of dust, raised by the violence of the winds above the 

 gloom of the dark, scorched, and desolate surface. 



It has been shown by the variation of light with phase that Mer- 

 cury must have a very rough and uneven soil; and his low albedo 

 seems to indicate the presence, on his superficies, of eruptive rocks, 

 of basalt and dark lava. The varying distance from the Sun must 

 tend slowly to disintegrate the rocks exposed to his heat, and this 

 process of destruction must be particularly active along the border- 

 land of the terminator, where the wilderness is exposed to awful 

 variations of temperature, ranging, indeed, over hundreds of degrees 

 Centigrade. 



" Mercury ", says Dr. Crommelin, " is probably a parched desert, 

 with nothing to mitigate the intense glare of the Sun on its day 

 side, seven times as fierce as we receive on Earth." ^ Professor Ait- 

 ken rightly considers that " the little planet is not fitted to be the 

 abode of life " * — a conclusion to which the late lamented E. W. 

 Maunder had independently arrived when he wrote that " the con- 

 ditions of Mercury are so unfavorable for life, that, even if this 

 remarkable relation of rotation period to revolution did not hold 

 good, it would still be impossible to regard it as a world for habi- 

 tation." ® 



» The star World, pp. 82-83. 



*Jourii. Roy. Astron, Soc. Canada, October 1911. 



•Are the Planets inhabited?, pp. 116-117. 



