The ca.n.a.ls which run along the bottom of the sea-beds are, of course, at a much lower level than the adjoining red area, and the ca.n.a.ls on the latter area are therefore at a higher level. Those ca.n.a.ls which cross the sea-beds cannot be carried by means of viaducts or embankments so as to place them upon the same level as the ca.n.a.ls on the red areas, because that would defeat the purpose of irrigation, which is their chief use. It is therefore necessary to lift the water from the low-level ca.n.a.ls and discharge it into those upon the higher ground.

This is accomplished by means of apparatus somewhat resembling an American "grain-elevator," on a large scale; and it consists of a long series of very large buckets, V-shaped in cross-section, attached to endless chain-bands, which, as they are carried round by the machinery, scoop up the water from the low-level ca.n.a.ls and carry it up to the requisite height, from whence it is automatically discharged into the high-level ca.n.a.ls. Of course it will be understood that the ends of the latter ca.n.a.ls are entirely closed by embankments so that no water can pa.s.s that way.

The buckets are an enormous size, and the electric machinery by which they are kept in motion is of the most ingenious description.

Besides this there is an immense amount of equally ingenious electrical machinery for forcing the water along the ca.n.a.ls.

Merna and Tellurio showed us all over the area, and carefully explained the construction and working of the various machines. I do not think M'Allister ever spent a more enjoyable time in his life, for he went about amongst the different machines examining them with the keenest interest and manifestations of delight; and his note-book was in constant requisition for making sketches and notes of what he saw.

We noticed that he was frequently smiling and chuckling to himself as if he were intensely pleased; and presently he came over to us, rubbing his hands together in high glee, and said to John, "Heh, mon, I reckon I see my way to making a fortune when we return home, out of the ideas and wrinkles I'm getting here from the work of the Martian engineers!"

John laughed, and congratulated him heartily on his brilliant outlook for the future, remarking that he did not appear to regret coming to Mars.

"Indeed, I don't," M'Allister replied; "I'm thinking it will prove the very best thing I've done in my life."

"Well, sir," said Merna, "I told you those machines would suit you as an engineer; are you satisfied now you have seen them?"

"More than satisfied," answered M'Allister; "they are the most extraordinary and most ingenious machines I ever saw, and I wouldn't have missed them for anything!"

At the sides of each high-level ca.n.a.l we saw a series of locks and weirs so constructed that vessels can pa.s.s on, in successive stages, from the high-level to the low-level ca.n.a.ls, and _vice versa_.

These locks and weirs are all within the area enclosed by the embankments forming the carets, which accounts for the long and extensive s.p.a.ce the latter cover, as the locks are necessarily a considerable distance apart from each other to allow for a length of ca.n.a.l to be traversed before the next lock is reached. They are, however, not in themselves sufficiently conspicuous to be separately discerned from the earth by our telescopic observers.

Machinery for forcing the water along the ca.n.a.ls is also provided at most of the junctions everywhere on the planet. In this connection it must be remembered that the water is carried by the ca.n.a.ls from one hemisphere to the other, and, after pa.s.sing the equator, must therefore move in a direction contrary to that of ordinary gravitation.

Thus at one season of the year the water pa.s.ses from the north polar regions down into the southern hemisphere, and at the opposite period of the year it is carried in the same way from the south polar regions right into the northern hemisphere.

Gravitation being almost non-effective as regards the flow of water on Mars, the movement would be extremely slow everywhere were it not for the machinery, which adds to the speed of the flow. The average rate of the movement of the water in the ca.n.a.ls is about fifty-one miles a day, and it takes about fifty-two days for the water to pa.s.s from about lat.i.tude 72 down to the equator, a distance of 2650 miles.

This rate of flow, as indicated by the darkening arising from the growth of vegetation which follows the flow of the water down the ca.n.a.ls, has been observed and noted many times at Flagstaff Observatory.

It was now perfectly clear to us why the "carets" are only seen in the particular places in which they have been observed by Professor Lowell and his colleagues. They are, in fact, only needed in connection with water-lifting apparatus, and locks and weirs, at the places where high-level ca.n.a.ls connect with those at a lower level!

We were all very pleased at finding the solution of a problem which had been much discussed between us without arriving at any satisfactory conclusion.

John then asked Tellurio if he would be good enough to explain to us how it was that our observers on the earth saw some of the Martian ca.n.a.ls doubled at some periods of the year and single at other times; and sometimes one of the twin ca.n.a.ls was seen alone, and at other times the second one only was visible.

"It is a very simple matter, sir," replied Tellurio. "You will understand that we do not wish to waste any of our water, and as it is quite unnecessary to use all our ca.n.a.ls at the same time, we only use those which are actually required. This arrangement also allows us to have a much greater depth of water in the ca.n.a.ls than would be the case if they were all in use at once.

"Many of the ca.n.a.ls are only required for irrigating seasonal crops; so as soon as the requisite amount of moisture has been acquired by the soil the water is turned from that ca.n.a.l into another one, pa.s.sing through an area where a later seasonal crop is to be grown. This arrangement, moreover, applies not only to our double ca.n.a.ls, but also to very many of the series which you have regarded as single ca.n.a.ls."

Thus the mysteries connected with Mars were being cleared up one after the other; and having regard to the very simple and natural explanations we received, we could not help laughing as we talked the matter over and recalled the immense amount of discussion and wrangling which had occurred amongst our scientific men in connection with these matters, and especially at the difficulty they seemed to experience in believing that the ca.n.a.ls could exist at all. Then there were those charges and theories of overstrained eyes, diplopia, and defective focussing, to say nothing of other suggestions. Well, I will not say any more upon this point.

In continuation of our discussion of the ca.n.a.l question, I asked Tellurio "Whether the ca.n.a.ls and irrigation system had been the means of reclaiming any large areas of land which had previously been deserts?"

"Oh yes, sir," he answered, "that has been the case in many parts of our world; some very large areas indeed which were once deserts have now become very fertile. Quite apart from such reclamations, however, our ca.n.a.ls and irrigation systems have also effectually checked the spread of desertism. If it had remained unchecked, probably by this time the entire surface of our planet would have become a desert."

I then explained that I asked the question because our observers had seen and noted upon their charts several large areas which seemed to have become fertile. Thus, along the eastern side of Thaumasia it had been noted that, during a period of about twenty-three years, the green area had advanced at least 400 miles nearer to the place we called the "Solar Lake." On measuring this area on the map it appeared to me that at least 200,000 square miles which had previously been desert had become fertile.

Similar extensions of vegetation had also been charted in several other places, for instance, on the east side of the large area known to us as "Syrtis Major." I had, however, been rather surprised not to have come across any comment by our scientists on the significance of this very large increase of fertile land, as, taken in connection with the great ca.n.a.l system, it seemed to me very significant and full of meaning.

Merna, continuing his remarks, then said that "Lately considerable extensions of their ca.n.a.l system had been carried out. New ca.n.a.ls had been dug, others altered or extended, and vast areas had been considerably changed by replanting in some places and fallowing in others. The result of all this work," he said, "would produce a striking alteration in the configuration of some of the dark areas. Such changes," he remarked, "were carried out very rapidly, so rapidly indeed that it would probably be almost incredible to terrestrials; but it must be remembered that excavation, loading and removal of soil, as well as most other operations, were accomplished by special machinery. He had no doubt these changes would be noted by our observers, as Mars was so favourably situated in regard to the earth at the present time. Besides this," he continued, "many of our ca.n.a.ls have been dealt with, and some of them will disappear, either temporarily or permanently."

"Well, Merna," said John, "if that is the case our observers will soon miss them; and I can imagine some of them gazing on your planet through their telescopes and exclaiming, 'Lo! here is the symbol of the death of Mars. Where we used to see ca.n.a.ls there is now only blank s.p.a.ce; the ca.n.a.ls are disappearing, and the Martians must be rapidly decreasing in numbers and no longer able to maintain their vast ca.n.a.l system; or perhaps their water supply is diminishing so rapidly that it is becoming insufficient to keep the ca.n.a.ls in working order; so ere long all life upon Mars must come to an end!'"

"If that should be so," said Merna, "they will be altogether wrong in their surmises, for the disappearance of several of our ca.n.a.ls will not indicate death but life. Some of those ca.n.a.ls will only be temporarily put out of use, but others, having served their purpose, will be discontinued permanently. They are like our flowers that have done blooming, which may be allowed to grow again next season, or the ground may be fallowed and fresh flowers planted elsewhere; so the vanished ca.n.a.ls may be succeeded by fresh ones where they are needed; and when your people see these new ca.n.a.ls they will _know_ that they indicate the continued existence of vigorous and enterprising life upon Mars."

We then started upon our return home, and on the way I drew M'Allister's attention to the smaller size of the sun as we saw it now as compared with the size it appeared to us when on the earth. I told him that Mars was then about 131,000,000 miles from the sun, so the sun's apparent diameter was only about 22-1/4 minutes.

On the earth that day the sun's apparent diameter would be about 32 minutes. So to the Martians the sun only appeared about two-thirds the size it appeared to the people on the earth.

When, on 13th August this year, Mars was at its "perihelion," or nearest point to the sun, the latter was 129,500,000 miles distant, and would appear rather more than 22-1/2 minutes in diameter.

At the opposite point of its...o...b..t, where it will be in "aphelion," or farthest from the sun, the sun will only appear about 19 minutes in diameter.

I then explained that, although the sun is so distant, Mars receives a very much larger percentage of the total heat and light available than we do on the earth, because of the thinness and generally cloudless condition of the atmosphere. It is estimated that our atmosphere and clouds shut out nearly 50 per cent. of the light and heat which would otherwise reach us in the course of the year. On the other hand, their "blanketing" effect considerably lessens the amount of heat radiated into s.p.a.ce; thus, by keeping in the heat we have received, compensating to some extent for the original loss in quant.i.ty.

But, owing to its thin clear atmosphere, Mars receives nearly 99 per cent. of the total amount of heat and light proceeding to it from the sun; so that, although the sun is more distant from the planet, the warmth on Mars does not compare so unfavourably with the warmth on the earth as many have imagined it to do.

M'Allister replied that "He had expected to find it very cold indeed upon Mars in consequence of its distance from the sun, but was surprised to find it so warm," and added, "what you have now told me, Professor, explains why this is so, and I can only say that at present I find the climate a delightful one--pleasantly warm, yet bracing and invigorating.

Even in the tropical regions, although it is hot, it is not the oppressive and enervating heat that I have experienced in the tropics on our own world."

He then remarked that "He knew the planets all moved through s.p.a.ce and had read that some of the stars did too, and he would like to know whether our sun had any motion in s.p.a.ce?"

"Yes," I replied; "as the result of a long series of observations and calculations it has been determined that the sun is moving through s.p.a.ce and carrying with it all the planets in our system. Its rate of movement is not known with certainty, but it is estimated at about 1,000,000 miles a day. Whether it is moving in a straight line or in a vast orbit around some far distant sun is also an open question, and it may take centuries to arrive at a definite result. This motion of our sun, rapid though it is, is very slow compared with the motion of some of the stars. One that appears only a small star to us, but which is probably a sun enormously larger than ours, is moving through s.p.a.ce at a rate which cannot be less than 200 miles a second; and unless that movement is direct across our line of sight its rate must be still more rapid.

Yet it is so enormously distant that, in 500 years, it would only appear to have moved over a s.p.a.ce of one degree on the sky! It is calculated that Arcturus moves still more rapidly.

"The movements of several other stars have been calculated; but the distance of the stars is so enormously great that the majority appear to have no movement at all, though probably not one of the heavenly bodies is at rest.

"It is estimated that the light of the nearest star we know of takes at least four years to reach the earth, yet light travels at the rate of 186,000 miles a second. We know of others whose light takes centuries to reach us, and, with regard to most of the stars, the light we see probably left them thousands of years ago.

"It is only when a star is so near to us that the earth's revolution in its...o...b..t is sufficient to cause a change in the apparent position of the star which can be measured with our instruments that any calculation can be made to determine its distance from us. In nearly all cases where the distance has been calculated, the change in position is so minute and difficult to measure accurately, that the results obtained can only be regarded as very rough approximations to the real distances.

"The universe is infinite in extent, and the human mind is quite unable to conceive what is really implied in the distances of the planets belonging to our own solar system; yet they are as nothing when compared with the distances of the fixed stars, either from the earth or from each other. We equally fail to realise the immense numbers of the stars. The camera, it is estimated, shows at least one hundred millions in the heavens; and our great telescopes can penetrate through inconceivable distances of s.p.a.ce and render visible millions which the smaller instruments fail to reveal. Every increase of instrumental power, however, carries us still farther, and reveals more and more stars in deeper depths of the illimitable abysses of s.p.a.ce.

"In these matters there is no finality, for though with telescopic aid:

'World after world, sun after sun, star after star are past, Yet systems round in myriads rise more glorious than the last: The wondrous universe of G.o.d still limitless is found, For endless are its distances, and none its depths can sound!'"

CHAPTER XXI

OUR FIRST VIEW OF THE EARTH FROM MARS--A MARTIAN COURTSHIP

Within a few days we had our first glimpse of the earth from Mars. It appeared only as a very thin but bright crescent of light, as the lighted portion was less than one-twelfth part of the whole diameter of the disc, and it was only visible for a very short time.