"Yes," Merna replied; "these embowered canals are very popular with the Martians, as they furnish such cool and pleasant walks in the summer time. I must also tell you," he added, "that those water-fowl are looked after with extreme care, because most of our aquatic birds have become nearly extinct since our natural areas of water failed us, and unless they were preserved would die out entirely. "You will understand that these canals are not liable to excessive evaporation; but, at the same time, it would not do to prevent evaporation altogether, because we should then fail to obtain a sufficient and fresh supply next spring." "I quite see that, Merna," I said; "but one of our scientific men has said that it would 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.