mentioned, we occasionally find parts of Mars rendered indistinct, it
must be acknowledged that the clouds on Mars are very slight. We should
expect that the polar caps, if composed of snow, would, when melting,
produce clouds which would more or less hide the polar regions from our
inspection; yet nothing of the kind has ever been seen.

We have seen that there are very grave doubts as to the existence of
water on Mars. No doubt we have frequently spoken of the dark markings
as "oceans" and of the bright parts as "continents." That this language
was just has been the opinion of astronomers for a very long time. A few
years ago Mr. Schaeberle, of the Lick Observatory, came to the very
opposite conclusion. He contended that the dark parts were the
continents and the bright ones were the oceans of water, or some other
fluid. He pointed to the irregular shading of the dark parts, which does
not suggest the idea of light reflected from a spherical surface of
water, especially as the contrasts between light and shade are strongest
about the middle of the disc.

It is also to be noticed that the dark regions are not infrequently
traversed by still darker streaks, which can be traced for hundreds of
miles almost in straight lines, while the so-called canals in the bright
parts often seem to be continuations of these same lines. Mr. Schaeberle
therefore suggests that the canals may be chains of mountains stretching
over sea and land! The late Professor Phillips and Mr. H.D. Taylor have
pointed out that if there were lakes or seas in the tropical regions of
Mars we should frequently see the sun directly reflected from them, thus
producing a bright, star-like point which could not escape observation.
Even moderately disturbed water would make its presence known in this
manner, and yet nothing of the kind has ever been recorded.

On the question as to the possibility of life on Mars a few words may be
added. If we could be certain of the existence of water on Mars, then
one of the fundamental conditions would be fulfilled; and even though
the atmosphere on Mars had but few points of resemblance either in
composition or in density to the atmosphere of the earth, life might
still be possible. Even if we could suppose that a man would find
suitable nutriment for his body and suitable air for his respiration, it
seems very doubtful whether he would be able to live. Owing to the small
size of Mars and the smallness of its mass in comp