he Canals. The dewfall on each
side is extensive, and the vegetal growth which extends the full length
of the water-ways and for thousands of miles in some cases, is most
prolific.

The water in the canals, in most instances, is distributed by gravity;
but recourse is had to a lock system and to immense pumps for raising
the water to proper levels.

The gates of the lock system and the pumps are operated by electricity,
the control of which energy is well understood by us. In fact, we are
centuries ahead of your Earth people in the knowledge of the use of
Electro-magnetic energy. (More will be given on the subject of
Electricity in a later chapter.)

Another source of mystery to your astronomers has been the appearance
of triangular dark spots at the origin of some of the Martian canals.
These have been referred to by your astronomer Lowell as "Carets,"
named so by reason of their peculiar shape. These so-called "Carets"
are the thoughtful provision for the impounding of a season's supply of
water. In other words they are in part a lock system for raising water
to the level of some of the main canals, and embrace also a prodigious
pumping system.

These so-called "Carets," as the telescope will show, are located at
the edge of some of what appear to you as very dark areas on our
planet. These dark areas are Mars' old sea bottoms, and in many
instances have been utilized by our engineers as natural reservoirs for
water. Their convenient location near the Poles has provided ideal
facilities for the preservation of an adequate supply of water.

The construction of Mars' gigantic Canal system, planetary in its
extent, might seem to your Earth people an impossible task. And it
might prove so to your Earth dwellers should you undertake a similar
project in the ages to come when your seas dry up, though it must be
remembered that gravity on Mars, compared with your Earth, is as 38 to
100. Excavations of large waterways then becomes a comparatively easy
task. We have no high mountains on Mars; in fact, none exceeding 3,000
feet in altitude.

Owing to the difference in gravity the angle of repose on Mars is
nearly acute as against 45 degrees on your Earth, which permits of
almost perpendicular walls to the canals and lessens the danger of
landslides and cave-ins. But above all, the biggest advantage enjoyed
by us in the construction of large public enterprises, such as are
embraced by our Canal system, is the so