canals were constructed, second and parallel waterways were made
for the purpose of guaranteeing an uninterrupted flow of water
from the Poles to the Equatorial regions. The result of this was
that on many occasions the foresight of the Martian engineers who
had the water supply of the planet in charge, saved immense areas
from drought.

The rainfall on Mars is almost nil and the immense population
(eight times larger than that of your Earth) is entirely
dependent on the water supply from the melting Polar caps. Water
on Mars is a most precious fluid and there is none to waste. Our
oceans evaporated ages ago, and outside of the precipitation of
moisture at the poles in the form of snow, none is to be had
anywhere else on the planet except in very meager quantities.

The astronomer Lowell of your Earth, who made a life study of our
planet, called these reservoirs "Oases," but he was mistaken in
his theory. He concluded that these points, which appear as
round disks in the telescope, were centers of population. This
conclusion is erroneous. The centers of population on Mars are
scattered over the entire planet regardless of the position of
the so-called "Oases." It is quite true that owing to the rapid
evaporation of water in the comparatively thin atmosphere of
Mars, the dewfall for quite a radius from the center of the
reservoirs is considerable, with the result that vegetation
springs up, giving the "Oases" the appearance of a diameter of
about 75 miles. The reservoirs are about 60 miles across and
hold millions of gallons of water.

The same explanation may be given of the Canals. The dewfall on