s our moon present very nearly the same face
to us, so Mercury presents always the same portion of its surface to the
sun.

It will be understood, therefore, that, theoretically, there must be on
Mercury but one spot where the sun always is directly overhead. It could
not be seen, however, owing to the dense clouds. This spot approximates
the center of the region known as the Fire Country.

So far as I could learn, it was here that human life on the planet began.
Certainly it was the first region where civilization reached any height.
When Columbus was discovering America great cities flourished in the Fire
Country--cities of untold wealth and beauty, now fallen into ruins like
the great cities of our own Aztec and Inca civilizations.

The Fire Country was then like the equatorial regions of earth--a dense,
tropic jungle, hotter than most temperatures we have to bear, but still,
by reason of its thick enveloping atmosphere of clouds, capable of
supporting life in comparative comfort. Its inhabitants were dark-skinned,
but rather more like our Indians than Negroid races.

Then, several centuries ago--the exact time is uncertain, for no written
records are kept on Mercury--came the Great Storms. Their cause was
unknown--some widespread atmospheric disturbance. These storms temporarily
parted the clouds in many places, allowing the direct rays of the sun to
fall upon the planet's surface. The resulting temperature destroyed all
life, withered all vegetation, with its scorching blast. The inhabitants
of the Fire Country were killed by hundreds of thousands, their cities
deserted, their land laid a desert waste.

These storms, which it appears began suddenly, have returned periodically
ever since, making the region practically uninhabitable. Its surviving
races, pushed outward toward the more temperate zone, were living, at this
time I am describing, in a much lower state of civilization than the
people of the Light Country--a civilization of comparative savagery. In
the Light Country they were held as slaves.

This region--thus very aptly known as the Fire Country--embraces a
circular area directly underneath the sun. So far as I could learn, it
extended outward roughly to those points where--if it had been
visible--the sun would have appeared some halfway between zenith and
horizon.

Lying outside the circle, in a larger, concentric ring, is the zone known
as the Light Country. Entirely free from the equatorial stor