We may add that in such a climate the frost will descend
principally upon the high ground at night time and in the
advancing day it will melt. The freer radiation brings about this
phenomenon among our own mountains in clear and calm weather.
With the progressive melting of the snow upon the pole Lowell
connected many phenomena upon the planet's surface of much
interest. The dark spaces appear to grow darker and more
greenish. The canals begin to show themselves and reveal their
double nature. All this suggests that the moisture liberated by
the melting of the polar snow with the advancing year, is
carrying vitality and springtime over the surface of the planet.
But how is the water conveyed?
Lowell believes principally by the canals. These are
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constructed triangulating the surface of the planet in all
directions. What we see, according to Lowell, is not the canal
itself, but the broad band of vegetation which springs up on the
arrival of the water. This band is perhaps thirty or forty miles
wide, but perhaps much less, for Lowell reports that the better
the conditions of observation the finer the lines appeared, so
that they may be as narrow, possibly, as fifteen miles. It is to
be remarked that a just visible dot on the surface of Mars must
possess a diameter of 30 miles. But a chain of much smaller dots
will be visible, just as we can see such fine objects as spiders'
webs. The widening of the canals is then accounted for, according
to Lowell, by the growth of a band of vegetation, similar to that
which springs into existence when the floods of the Nile irrigate
the plains of Egypt.
If no other explanation of the lines is forthcoming than that
they are the work of intelligence, all this must be remembered.
If all other theories fail us, much must be granted Lowell. We
must not reason like fishes—as Lowell puts it—and deny that
intelligent beings can thrive in an atmospheric pressure of four
and half inches of mercury. Zurbriggen has recently got to the
top of Aconcagua, a height of 24,000 feet. On the summit of such
a mountain the barometer must stand at about ten inches. Why
should not beings be developed by evolution with a lung capacity
capable of living at two and a half times this altitude. Those
steadily
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curved parallel lines are, indeed, very unlike anything we have
experience of. It would be rather to be expected that another
civilisation than our own would present many wide differences in
its development.
What then is the picture we have before us according to Lowell?
It is a sufficiently dramatic one.
Mars is a world whose water supply, never probably very abundant,
has through countless years been drying up, sinking into his
surface. But the inhabitants are making a brave fight for it,
They have constructed canals right round their world so that the
water, which otherwise would run to waste over the vast deserts,
is led from oasis to oasis. Here the great centres of
civilisation are placed: their Londons, Viennas, New Yorks. These
gigantic works are the works of despair. A great and civilised
world finds death staring it in the face. They have had to triple
their canals so that when the central canal has done its work the
water is turned into the side canals, in order to utilise it as
far as possible. Through their splendid telescopes they must view
our seas and ample rivers; and must die like travellers in the
desert seeing in a mirage the cool waters of a distant lake.