comparatively narrow canals, running parallel to each other, with a very wide strip of vegetation between each. Usually the canals were linked together in pairs by smaller cross canals running diagonally from one canal to the other in alternate order. These were the irrigation trenches. Thus from one of a pair of canals an irrigation trench would branch out at an angle of about fifty degrees, and enter the second canal. Higher up, on the same side, another trench would run from the second canal at a similar angle, and enter the first canal, and so on—ad infinitum. In the case of single canals curved loops branched out and re-entered higher up, these loops being made on either side, and similar loops were made on the outsides of paired canals.
As a result of this arrangement it did not matter whether the water passed up the canal at one season of the year or down it at another season, it could always move straight ahead; the irrigation trenches were thus constantly flushed by one or other of the pairs, and there could be no stagnation anywhere. Merna also told us that some canals are provided with a network of trenches, whilst others are embanked so that the water can be let out through sluices when necessary, and thus flood the surrounding land. Thus every requirement can be met.
So far from being a hundred miles wide, it was exceptional for the canals to have a width of more than two hundred yards. Most of those we were looking at were only about sixty feet wide! and only the wider ones are used for navigation purposes. Merna explained why this was so, saying that as the main use of the canals was for irrigation purposes very wide ones were not required; for not only would they be wasteful, but as it was necessary to force the water along by artificial means, it could more conveniently be accomplished in the case of narrow canals, as the wider the canal the more difficult it became to force the water along.
We also observed many splendid wide motor-roads running between the single canals, as well as others running straight across the system, being carried over the canals by the most beautiful and fairy-like bridges that we had ever seen. They were all constructed of a metal identical with our “martalium,” which we had used in the construction of the Areonal; so that was undoubtedly another invention which we owed to Martian influences transmitted to us across space!
Nothing more beautiful or graceful than these bridges could be imagined, so light were they in construction, so elegant and varied in design, and every part shining in the sun like burnished silver; they looked like structures composed of rays of light rather than substantial metal! They were a perfect dream of beauty, and we stood a long time examining their elegant construction through our glasses.
“Well,” remarked John, “some of our millionaires would give half their fortunes to have such lovely bridges as these in their private parks!”
“Heh, mon!” replied M’Allister, “it’s very clear the Martians could teach our engineers something about bridge-building, if nothing else!”
“Wait and see our water-lifting and water-propelling machinery,” said Merna; “I think that will be something which will suit you as an engineer!”
I noticed that many of the lines were apparently groves of trees, and asked Merna whether they were canals or not.
“Yes,” he replied, “they are canals. You will understand that in the hotter parts of our world it is necessary to protect the water from too rapid evaporation, or else the canals would be almost run dry long before the need for their use ceased at the end of the season. Some are arched over entirely, but in most cases it is sufficient to plant trees along each side. Would you like to examine one?” he asked; “we can do so very soon, if you wish?”
I said I should be glad to do so, and our course was accordingly directed to one of the groves, which appeared to be about two miles distant. It, however, proved to be more than six miles away, for we had not yet become accustomed to the effect of the clear Martian air in making distant objects appear much closer than they really were. However, it did not take long for our air-ship to reach it; and we descended in the space between the canals and then walked over into the grove. When we turned into it, we were greatly surprised at the charming effect of the trees over the canal.
The trees were something like our willows, but taller than elms, and had a multitude of very long, thin, and supple branches, with very little bare trunk. They were planted rather close together, all along each side of the canal, with their trunks sloping slightly towards the water. The long branches thus met at the sides and high overhead, intertwining together, and forming a high leafy archway extending all along the canal in both directions as far as the eye could see. The thick, soft Martian grass along each side of the canal was like a velvet-pile carpet to walk upon; the sunlight filtering between the green leaves of the trees cast bright flecks of light on the clear shimmering water which ran beneath them; whilst water-fowl swimming here and there gave a bright touch of colour and the animation of life which so adds to the general charm of such scenery. Some of the water-fowl were very large birds, with brilliant coloured plumage.
“What a delightful place for a quiet walk on a hot day like this,” I exclaimed; “plenty of air and no excess of heat!”
“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.
“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 people imagine! Why, I’ve read that the need of water here must be so great that the people, driven to desperation, must be fighting each other to extermination in order to get it.”
“That is an entirely erroneous idea, sir,” replied Merna; “and you may be quite sure that such a state of affairs will never be witnessed upon this planet. We know the time must come when our water supply will cease to be, but your people are needlessly pessimistic, and imagine terrors where we see none.
“In actual time, the end of Mars is still far distant; but, as compared with that of your world, it is very near. It will be possible, later on, to forecast, by means of our records of the rate of decrease, the time when our water supply will come to an end; but even now it is well understood how the crisis will be met. As the final period draws
