e of a great sheet of water. Lastly, they are
observed to vary in tone and colour with the changing Martian seasons,
the blue-green changing into ochre, and later on back again into
blue-green. Professor Lowell regards these areas as great tracts of
vegetation, which are brought into activity as the liquid reaches them
from the melting snows.

[Illustration: PLATE XII. A MAP OF THE PLANET MARS

We see here the Syrtis Major (or "Hour-Glass Sea"), the polar caps,
several "oases," and a large number of "canals," some of which are
double. The South is at the top of the picture, in accordance with the
_inverted_ view given by an astronomical telescope. From a drawing by
Professor Percival Lowell.

(Page 216)]

With respect to the canals, the Lowell observations further inform us
that these are invisible during the Martian winter, but begin to appear
in the spring when the polar cap is disappearing. Professor Lowell,
therefore, inclines to the view that in the middle of the so-called
canals there exist actual waterways which serve the purposes of
irrigation, and that what we see is not the waterways themselves, for
they are too narrow, but the fringe of vegetation which springs up along
the banks as the liquid is borne through them from the melting of the
polar snows. He supports this by his observation that the canals begin
to appear in the neighbourhood of the polar caps, and gradually grow, as
it were, in the direction of the planet's equator.

It is the idea of life on Mars which has given this planet such a
fascination in the eyes of men. A great deal of nonsense has, however,
been written in newspapers upon the subject, and many persons have thus
been led to think that we have obtained some actual evidence of the
existence of living beings upon Mars. It must be clearly understood,
however, that Professor Lowell's advocacy of the existence of life upon
that planet is by no means of this wild order. At the best he merely
indulges in such theories as his remarkable observations naturally call
forth. His views are as follows:--He considers that the planet has
reached a time when "water" has become so scarce that the "inhabitants"
are obliged to employ their utmost skill to make their scanty supply
suffice for purposes of irrigation. The changes of tone and colour upon
the Martian surface, as the irrigation produces its effects, are similar
to what a telescopic observer--say, upon Venus--would notice on our
earth when