than on the
earth, and the amount of labour required to do such work as digging or
lifting would be lessened. There would, for the same reason, be greater
ease of movement in walking, jumping, or running, and large bulky
animals like our elephants could move with almost the same ease and
freedom as our goats.

"Theoretically, we should expect to find the atmosphere upon Mars very
much thinner than our atmosphere, and actual observation proves this to
be the case. We are able to see details on the surface of Mars with very
much greater distinctness than would be the case if its atmosphere were
as dense as ours. Moreover, clouds are comparatively rarely seen; and
the majority that are observed present more the appearance of clouds of
sand than rain clouds. Usually, also, they float very much higher above
the planet's surface than our clouds are above the earth's surface; ten
miles high is quite an ordinary altitude, and some have been estimated
as quite thirty miles above the planet.

"Many theorists have attempted to prove that, owing to the planet's
distance from the sun, and the thinness of its atmosphere, the
temperature of Mars must be very low, probably below freezing-point even
at the equator. Dr. Alfred Russel Wallace has gone further than this,
and suggests that the temperature must be eighty degrees Centigrade
below freezing-point; that there is no water or water vapour on the
planet; and that it is quite impossible for life to exist there!

"However, as the result of delicate bolometric experiments, careful
calculations, and consideration of conditions affecting the result which
have not previously received so much attention, Professor Very has
arrived at a different opinion; and actual observation has shown that
there is very little indication of frost outside the frigid zones. Even
in the polar regions it is at times evidently warmer than at the earth's
poles, because during the spring and summer the snow-caps upon Mars not
only melt more rapidly, but melt to a much greater extent than our polar
caps do. In 1894 the southern polar snow-cap of Mars was observed almost
continuously during the melting period, and it was actually observed to
dwindle and dwindle until it had entirely disappeared. It is rather
strange to think that we know more about the snow-caps of that
far-distant world than we do about those on our own earth.

"Owing to the lesser gravity on Mars the snow and ice which forms the
caps would