as far as the force of gravity may be considered as the decisive factor,
Mars could be inhabited by giants fifteen feet tall, who would be
relatively just as active, and just as little impeded in their movements
by the weight of their bodies, as a six-footer is upon the earth. But
they would possess far more physical strength than we do, while, in
doing work, they would have much lighter materials to deal with.

Whether the theory that the canals of Mars really are canals is true or
not, at any rate there can now be no doubt as to the existence of the
strange lines which bear that designation. The suggestion has been
offered that their builders may no longer be in existence, Mars having
already passed the point in its history where life must cease upon its
surface. This brings us to consider again the statement, made near the
beginning of this chapter, that Mars is, perhaps, at a more advanced
stage of development than the earth. If we accept this view, then,
provided there was originally some resemblance between Mars's life forms
and those of the earth, the inhabitants of that planet would, at every
step, probably be in front of their terrestrial rivals, so that at the
present time they should stand well in advance. Mr. Lowell has, perhaps,
put this view of the relative advancement in evolution of Mars and its
inhabitants as picturesquely as anybody.

"In Mars," he says, "we have before us the spectacle of a world
relatively well on in years, a world much older than the earth. To so
much about his age Mars bears witness on his face. He shows unmistakable
signs of being old. Advancing planetary years have left their mark
legible there. His continents are all smoothed down; his oceans have all
dried up.... Mars being thus old himself, we know that evolution on his
surface must be similarly advanced. This only informs us of its
condition relative to the planet's capabilities. Of its actual state our