contending winds and tempests, where the moisture, if there be any, is
precipitated, through the rapid cooling of the air, in whelming floods
and wild snow-storms driven by hurrying blasts from the realm of endless
night.

Enough seems now to have been said to indicate clearly the hopelessness
of looking for any analogies between Mercury and the earth which would
warrant the conclusion that the former planet is capable of supporting
inhabitants or forms of life resembling those that swarm upon the
latter. If we would still believe that Mercury is a habitable globe we
must depend entirely upon the imagination for pictures of creatures able
to endure its extremes of heat and cold, of light and darkness, of
instability, swift vicissitude, and violent contrast.

In the next chapter we shall study a more peaceful and even-going world,
yet one of great brilliancy, which possesses some remarkable
resemblances to the earth, as well as some surprising divergences from
it.




CHAPTER III

VENUS, THE TWIN OF THE EARTH


We come now to a planet which seems, at the first glance, to afford a
far more promising outlook than Mercury does for the presence of organic
life forms bearing some resemblance to those of the earth. One of the