be madness to construct canals on Mars, because the
water would all quickly evaporate, especially in the warmer regions, and
thus be wasted."

"Well, as you see, sir, we manage to prevent evaporation to any extent
we may desire," replied Merna with a smile; "and even scientific men
seem liable to omit some important matters from their theories and
calculations."

"How do you manage the irrigation?" I inquired; "the trenches seem
rather wide apart to supply such a large area!"

"The upper layer of soil is very porous, and the water soaks along it,"
he answered; adding that "where necessary it was assisted by porous
pipes laid beneath the surface.

"Besides," he proceeded, "we have small portable electric engines, with
which water from the trenches can be distributed in the form of spray
over wide areas. Our vegetation, too, has adapted itself to the
conditions of the planet in the course of the changes which have taken
place during past ages, and now requires very little water or moisture
to maintain it in vigorous and healthy growth."

One more question was put to him by John, who asked, "Do these canals
constitute your whole supply of water for drinking, as well as for all
other purposes?"

"Oh no, John!" exclaimed Merna. "We draw all our pure water from deep
wells. The soil of Mars, being much more lightly compacted than that of
the earth, has absorbed an immense proportion of the water which was
formerly upon its surface. Instead of having lost it by evaporation and
radiation into space, we still have it below the surface, stored up
ready for use in our time of need.

"For this reason, and also in consequence of the small amount of our
planet's internal heat, the water has not undergone chemical change, and
mostly lies at great depths; but, of course, well-boring is much easier
work than on your world, and I expect our methods are rather in advance
of yours.

"Your scientists seem to have overlooked some of these points
altogether. You need not pity us for lack of water, as I have heard you
doing, for we have an ample supply for many centuries to come;
especially as we can purify water which has been used for general
purposes, and store it up for use, over and over again. Our canals are
only drawn upon for purposes connected with irrigation, or when
absolutely pure water is not needed."

"Well," M'Allister exclaimed, "it doesn't seem that the Martians are so
badly off for water as some of our clever peop