sun is barely half of that received by this world.
It must be, if the nebular hypothesis has any truth, older than our
world; and long before this earth ceased to be molten, life upon its
surface must have begun its course. The fact that it is scarcely one
seventh of the volume of the earth must have accelerated its cooling
to the temperature at which life could begin. It has air and water
and all that is necessary for the support of animated existence.

Yet so vain is man, and so blinded by his vanity, that no writer,
up to the very end of the nineteenth century, expressed any idea that
intelligent life might have developed there far, or indeed at all,
beyond its earthly level. Nor was it generally understood that since
Mars is older than our earth, with scarcely a quarter of the
superficial area and remoter from the sun, it necessarily follows that
it is not only more distant from time's beginning but nearer its end.

The secular cooling that must someday overtake our planet has
already gone far indeed with our neighbour. Its physical condition is
still largely a mystery, but we know now that even in its equatorial
region the midday temperature barely approaches that of our coldest
winter. Its air is much more attenuated than ours, its oceans have
shrunk until they cover but a third of its surface, and as its slow
seasons change huge snowcaps gather and melt about either pole and
periodically inundate its temperate zones. That last stage of
exhaustion, which to us is still incredibly remote, has become a
present-day problem for the inhabitants of Mars. The immediate
pressure of necessity has brightened their intellects, enlarged their
powers, and hardened their hearts. And looking across space with
instruments, and intelligences such as we have scarcely dreamed of,
they see, at its nearest distance only 35,000,000 of miles sunward of
them, a morning star of hope, our own warmer planet, green with
vegetation and grey with water, with a cloudy atmosphere eloquent of
fertility, with glimpses through its drifting cloud wisps of broad
stretches of populous country and narrow, navy-crowded seas.

And we men, the creatures who inhabit this earth, must be to them
at least as alien and lowly as are the monkeys and lemurs to us. The
intellectual side of man already admits that life is an incessant
struggle for existence, and it would seem that this too is the belief
of the minds upon Mars. Their world is far gone in