wo
inches of water. From this scanty and inadequate supply of two inches of
water allowance must be made for an enormous loss by evaporation; so, as
the writer said, "the polar reservoirs are despoiled in the act of being
opened."

Tellurio at once settled the matter by saying, "Mr. Poynders, it is a
very pretty theory, but, unfortunately for its supporters, it is
entirely wrong, the figures being inaccurate, and the estimate of the
extent of the area to be supplied, as well as the amount of water
available, is made under a complete misapprehension of the facts."

[Illustration: _From a Globe made by M. Wicks_ Plate XIV

MARS. MAP VII

The white area at the top of this map is the south polar snow-cap, at
about its usual maximum size. In some hard winters it attains a diameter
of considerably over 100 degrees.]

"The maximum area of the south polar snow-cap is usually more than
10,000,000 square miles instead of less than 2,500,000 as stated, but it
is sometimes still greater during a hard winter. Then, where did the
writer acquire the notion that the whole of the dark areas had to be
covered with water? Only the canals and trenches have to be filled, and,
at the highest computation, these would cover only 2,250,000 square
miles! So even accepting her average of twenty feet depth of the snow
(which would give about one foot of water over the whole area of the
snow-cap), there would still be sufficient water to fill every canal and
trench upon our planet to a depth of nearly four feet six inches.

"Let us suppose we have 700 series of canals, each averaging 1400 miles
in length, and each series having an aggregate width (including the area
of the irrigation trenches) of 2-1/4 miles. You will see that gives
about 2,250,000 square miles to be covered with water. My estimate of
the area to be covered is, however, much in excess of the real amount,
as the average aggregate width of the series of canals would be less
than I have assumed, and the trenches are shallow.

"I must also point out that only a small proportion of the whole number
of canals would be in use at any given time, and the depth of the polar
snows averages considerably more than twenty feet; so a very much
greater depth of water can be secured in those canals which are in use.
The main canals which are used for navigation purposes are, of course,
much wider and deeper than the irrigation canals. In the hotter regions
many covered compensation reservoi