conditions of Mars. In concluding this portion
of my discussion of the problem of Mars, I wish to call attention to the
fact that my argument, founded upon a comparison of the physical
conditions of the earth and moon with those of Mars, is dependent upon a
small number of generally admitted scientific facts; while the
conclusions drawn from those facts are simple and direct, requiring no
mathematical knowledge to follow them, or to appreciate their weight and
cogency. I claim for them, therefore, that they are in no degree
speculative, but in their data and methods exclusively scientific. In
the next chapter I will put forward a suggestion as to how the very
curious markings upon the surface of Mars may possibly be interpreted,
so as to be in harmony with the planet's actual physical condition and
its not improbable origin and past history.

CHAPTER VII.

A SUGGESTION AS TO THE 'CANALS' OF MARS.

The special characteristics of the numerous lines which intersect the
whole of the equatorial and temperate regions of Mars are, their
straightness combined with their enormous length. It is this which has
led Mr. Lowell to term them 'non-natural features.' Schiaparelli, in his
earlier drawings, showed them curved and of comparatively great width.
Later, he found them to be straight fine lines when seen under the best
conditions, just as Mr. Lowell has always seen them in the pure
atmosphere of his observatory. Both of these observers were at first
doubtful of their reality, but persistent observation continued at many
successive oppositions compelled acceptance of them as actual features
of the planet's disc. So many other observers have now seen them that
the objection of unreality seems no longer valid.

Mr. Lowell urges, however, that their perfect straightness, their
extreme tenuity, their uniformity throughout their whole length, the
dual character of many of them, their relation to the 'oases' and the
form and position of these round black spots, are all proofs of
artificiality and are suggestive of design. And considering that some of
them are actually as long as from Boston to San Francisco, and
relatively to their globe as long as from London to Bombay, his
objection that "no natural phenomena within our knowledge show such
regularity on such a scale" seems, at first, a mighty one.

It is certainly true that we can point to nothing exactly like them
either on the earth or on the moon, and these are the on