ing the early summer. As there is no
permanent glaciation on a planet which has lost its water, the snow-cap
would melt to a very large extent, and the resultant water must go
somewhere.

"'The inhabitants of the planet could not exist without water, and
their land would become entirely desert unless supplied with moisture.
It will, therefore, be seen that the only thing possible, as a means of
self-preservation, would be for them to make channels to carry the water
in the most economical way from the poles to the parts where it was
needed. Unless they found a means of doing this death stared them in the
face. What greater incentive could there be!'

"This is what Professor Lowell is convinced has actually been
accomplished upon Mars, with the result that there is a network of
canals all over the planet by which water is conveyed from each pole and
carried across from one hemisphere into the other. The lines seen show
where the canals are, but not the canals themselves, because they are
too narrow to be seen. The lines really are broad bands of vegetation
irrigated by the canals which run through them, hence the seasonal
changes which have been noted in their colour.

"All this seems very reasonable, deduced as it is from scientific fact
and from the many different things which have actually been seen and
confirmed by many thousands of observations, but it has met with the
most bitter opposition on the part of many astronomers, both
professional and amateur. Theory after theory has been brought forward
with the object of disproving the existence of the canal lines; some of
these, such as eye-strain, diplopia, bad focussing, illusion, and
imagination, have already been mentioned.

"Proofs of the reality of the lines having become too strong for most of
the objectors, they then turned their endeavours to the overthrowing of
the theory that the lines were canals, suggesting that they were all of
natural origin.

"Amongst these suggestions it was stated they were edges of shadings,
natural growths of long lines of trees and vegetation, cracks in the
surface of the planet or foldings caused by contraction, trap-dykes,
&c., but not one of these suggestions will bear investigation. I have
already pointed out the impossibility of shadings having straight edges
for thousands of miles in so many hundreds of cases. It is equally
impossible to imagine natural growths of trees and vegetation in bands
of uniform width and thous