except Smith kept close watch on the ground below. They made out town
after town, as well as separate buildings; and on the roads were to be
seen a great many of those octagonal structures, all motionless.

After several hundred miles of this, the surface abruptly sloped toward
what had clearly been the bed of an ocean. No sign of habitations here,
however; so apparently the water had disappeared AFTER the humans had
gone.

This ancient sea ended a short distance from the district they were
seeking. A little more travel brought them to a point where the sun cast
as much shadow as light on the surface. It was here they descended,
coming to rest on a sunlit knoll which overlooked a small, building-
filled valley.

According to Kinney's apparatus, there was about one-fortieth the amount
of air that exists on the earth. Of water vapor there was a trace; but
all their search revealed no human life. Not only that, but there was no
trace of lower animals; there was not even a lizard, much less a bird.
And even the most ancient-looking of the sculptures showed no creatures
of the air; only huge, antediluvian monsters were ever depicted.

They took a great many photos as a matter of course. Also, they
investigated some of the big, octagonal machines in the streets, finding
them to be similar to the great "tanks" that were used in the war,
except that they did not have the characteristic caterpillar tread;
their eight faces were so linked together that the entire affair could
roll, after a jolting, slab-sided, flopping fashion. Inside were curious
engines, and sturdy machines designed to throw the cannon-shells they
had seen; no explosive was employed, apparently, but centrifugal force