Mars (Lowell)/Chapter 4
IV
CANALS
I. FIRST APPEARANCES
In the last chapter we saw how badly off for water Mars, to all appearance, is; so badly off that inhabitants of that other world would have to irrigate to live. As to the actual presence there of such folk, the broad physical characteristics of the planet express no opinion beyond the silence of consent, but they have something very vital to say about the conditions under which alone their life could be led. They show that these conditions must be such that in the Martian mind there would be one question perpetually paramount to all the local labor, women's suffrage, and Eastern questions put together—the water question. How to procure water enough to support life would be the great communal problem of the day.
Were Mars like the Earth, we might well despair of detecting signs of any Martians for some time yet. Across the gulf of space that separates us from Mars, an area thirty miles wide would just be perceptible as a dot. It would, in such case, be hopeless to look for evidence of folk. Anything like London or New York, or even Chicago in its own estimation would be too small to be seen, so sorry a figure does man cut upon the Earth he thinks to own. From the standpoint of forty millions of miles distance, probably the only sign of his presence here would be such semi-artificialities as the great grain-fields of the West when their geometric patches turned with the changing seasons from ochre to green, and then from green to gold. By his crops we should know him. A tell-tale fact this, for it would be still more likely to be the case with Mars. If the surface of the planet were cultivated at all, it would probably be upon a much more thorough plan than is the case with the Earth. Conditions hold there which would necessitate a much more artificial state of things. If cultivation there be, it must be cultivation largely dependent upon a system of irrigation, and therefore much more systematic than any we have as yet been forced to adopt.
Now, at this point in our investigation, when the broad features of Mars disclose conditions which imply irrigation as their organic corollary, we are suddenly confronted on the planet's face with phenomena so startlingly suggestive of this very thing as to seem its uncanny presentment. Indeed, so amazingly lifelike is their appearance that, had we possessed our present knowledge of the planet's physical condition before, we might almost have predicted what we see as criterion of the presence of living beings. What confronts us is this:—
When the great continental areas, the reddish-ochre portions of the disk, are attentively examined in sufficiently steady air, their desert-like ground is seen to be traversed by a network of fine, straight, dark lines. The lines start from points on the coast of the blue-green regions, commonly well-marked bays, and proceed directly to what seem centres in the middle of the continent, since most surprisingly they meet there other lines that have come to the same spot with apparently a like determinate intent. And this state of things is not confined to any one part of the planet, but takes place all over the reddish-ochre regions.
The lines appear either absolutely straight from one end to the other, or curved in an equally uniform manner. There is nothing haphazard in the look of any of them. Plotting upon a globe betrays them to be arcs of great circles almost invariably, even the few outstanding exceptions seeming to be but polygonal combinations of the same. Their most instantly conspicuous characteristic is this hopeless lack of happy irregularity. They are, each and all, direct to a degree.
The lines are as fine as they are straight. As a rule, they are of scarcely any perceptible breadth, seeming on the average to be less than a Martian degree, or about thirty miles wide. They differ slightly among themselves, some being a little broader than this; some a trifle finer, possibly not above fifteen miles across. Their length, not their breadth, renders them visible; for though at such a distance we could not distinguish a dot less than thirty miles in diameter, we could see a line of much less breadth, because of its length. Speaking generally, however, the lines are all of comparable width.
Still greater uniformity is observable in different parts of the same line; for each line maintains its individual width, from one end of its course to the other. Although, at and near the point where it leaves the dark regions, some slight enlargement seems to occur, after it has fairly started on its course, it remains of substantially the same size throughout. As to whether the lines are even on their edges or not, I should not like to say; but the better they are seen, the more even they look. It is not possible to affirm positively on the point, as they are practically nearer one dimension than two.
On the other hand, their length is usually great, and in cases enormous. A thousand or fifteen hundred miles may be considered about the average. The Ganges, for example, which is not a long one as Martian canals go, is about 1,450 miles in length. The Brontes, one of the newly discovered, radiating from the Gulf of the Titans, extends over 2,400 miles; while, among really long ones, the Eumenides, with its continuation the Orcus, the two being in truth one line, measures 3,540 miles from the point where it leaves the Phoenix Lake to the point where it enters the Trivium Charontis,—throughout this whole distance, nearly equal to the diameter of the planet, deviating neither to the right nor to the left from the great circle upon which it set out. On the other hand, the shortest line is the Nectar, which is only about 250 miles in length; sweetness being, according to Schiaparelli its christener, as short-lived on Mars as elsewhere.
That, with very few exceptions, the lines all follow arcs of great circles is proved,—first, by the fact that, when not too long, they show as straight lines; second, that, when seen near this limb, they appear curved, in keeping with the curvature of a spherical surface viewed obliquely; third, that, when the several parts of some of the longer lines are plotted upon a globe, they turn out to lie in one great circle. Apparent straightness throughout is only possible in comparatively short lines. For a very long arc upon the surface of a revolving globe tilted toward the observer to appear straight it, or its prolongation, must pass through the centre of the disk at the moment. Such, of course, is rarely the case. At times, however, the conditions are strikingly fulfilled by the great canal called the Titan. The Titan starts from the Gulf of the Titans, in south latitude 20°, and runs north almost exactly upon the 169th meridian for an immense distance. I have followed it over 2,300 miles down the disk to about 43° north, as far as the tilt of the planet's axis would permit. As the rotation of the planet swings it round, it passes the central meridian of the disk simultaneously throughout its length, and at that moment comes out so strikingly straight it seems a substantialized meridian itself.
Although each line is the arc of a great circle, the direction taken by this great circle may be any whatsoever. The Titan, as we have seen, runs nearly due north and south. Certain canals crossing this run, on the contrary, almost due east and west. There are others again, belting the disk at well-nigh every angle between these two extremes. Nor is there any preponderance, apparently, for one direction as against any other. This indifference to direction is important as showing that the rotation of the planet has no bearing upon the inclination of the canals.
But, singular as each line looks to be by itself, it is the systematic network of the whole that is most amazing. Each line not only goes with wonderful directness from one point to another, but at this latter spot it contrives to meet, exactly, another line which has come with like directness from quite a different direction. Nor do two only manage thus to rendezvous. Three, four, five, and even seven will similarly fall in on the same spot,—a gregariousness which, to a greater or less extent, finds effective possibility all over the surface of the planet. The disk is simply a network of such intersections. Sometimes a canal goes only from one intersection to another; more commonly it starts with right of continuation, and, after reaching the first rendezvous, goes on in unchanged course to several more.
The result is that the whole of the great reddish-ochre portions of the planet is cut up into a series of spherical triangles of all possible sizes and shapes. What their number may be lies quite beyond the possibility of count at present; for the better our own air, the more of them are visible. About four times as many as are down on Schiaparelli's chart of the same regions have been seen at Flagstaff. But, before proceeding further with a description of these Martian phenomena, the history of their discovery deserves to be sketched here, since it is as strange as the canals themselves.
The first hint the world had of their existence was when Schiaparelli saw some of the lines in 1877, now eighteen years ago. The world, however, was anything but prepared for the revelation, and, when he announced what he had seen, promptly proceeded to disbelieve him. Schiaparelli had the misfortune to be ahead of his times, and the yet greater misfortune to remain so; for not only did no one else see the lines at that opposition, but no one else succeeded in doing so at subsequent ones. For many years fate allowed Schiaparelli to have them all to himself, a confidence he amply repaid. While other's doubted, he went from discovery to discovery. What he had seen in 1877 was not so very startling in view of what he afterward saw. His first observations might well have been of simple estuaries, long natural creeks running up into the continents, and even cutting them in two. His later observations were too peculiar to be explained, even by so improbable a configuration of the Martian surface. In 1879 the canali, as he called them (channels, or canals, the word may be translated, and it is in the latter sense that he now regards them), showed straighter and narrower than they had in 1877: this not in consequence of any change in them, but from his own improved faculty of detection; for what the eye has once seen it can always see better a second time. As he gazed they appeared straighter, and he made out more. Lastly, toward the end of the year, he observed one evening what struck even him as a most startling phenomenon,—the twinning of one of the canals: two parallel canals suddenly showed where but a single one had showed before. The paralleling was so perfect that he suspected optical illusion. He could, however, discover none by changing his telescopes or eye-pieces. The phenomenon, apparently, was real.
At the next opposition he looked to see if by chance he should mark a repetition of the strange event, and went, as he tells us, from surprise to surprise; for one after another of his canals proceeded startlingly to become two, until some twenty of them had thus doubled. This capped the climax to his own wonderment, and, it is needless to add, to other people's incredulity; for nobody else had yet succeeded in seeing the canals at all, let alone seeing them double. Undeterred by the general skepticism, he confirmed at each fresh opposition his previous discoveries, which, in view of the fact that no one else did, tended in astronomical circles to an opposite result.
For nine years he labored thus alone, having his visions all to himself. It was not till 1886 that any one but he saw the canals. In April of that year Perrotin, at Nice, first did so. The occasion was the setting up of the great Nice glass of twenty-nine inches aperture. In spite of the great size of the glass, however, a first attempt resulted in nothing but failure. So, later, did a second, and Perrotin was on the point of abandoning the search for good, when, on the 15th of the month, he suddenly detected one of the canals, the Phison. His assistant, M. Thollon, saw it immediately afterward. After this they managed to make out several others, some single, some double, substantially as Schiaparelli had drawn them; the slight discrepancies between their observations and his being in point of fact the best of confirmations.
Since then, other observers have contrived to detect the canals, the list of the successful increasing at each opposition, although even now their number might almost be told on one's hands and feet.
The reason that so few astronomers have as yet succeeded in seeing these lines is to be found in our own atmosphere. That in ordinary atmosphere the lines are not easy objects is certain. A moderately good air is essential to their detection; and unfortunately the locations of most of our observatories preclude this prerequisite. Size of aperture of the telescope used is a very secondary matter. That Schiaparelli discovered the canals with an 8 1/3-inch glass, and that the 26-inch glass at Washington Plate XVIII
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FASTIGIUM ARYN
October, 1894
The importance of atmosphere in the study of planetary detail is far from being appreciated. It is not simply question of a clear air, but of a steady one. To detect fine detail, the atmospheric strata must be as evenly disposed as possible.
Next in importance to a steady air comes attentive perception on the part of the observer. The steadiest air we can find is in a state of almost constant fluctuation. In consequence, revelations of detail come only to those who patiently watch for the few good moments among the many poor. Nor do I believe even average air to be entirely without such happy exceptions to a general blur. In these brief moments perseverance will show the canals as faint streaks. To see them as they are, however, an atmosphere possessing moments of really distinct vision is imperative. For the canals to come out in all their fineness and geometrical precision, the air must be steady enough to show the markings on the planet's disk with the clear-cut character of a steel engraving. No one who has not seen the planet thus can pass upon the character of these lines.
Although skepticism as to the existence of the so-called canals has been now pretty well dispelled by these and other observations, disbelief still makes a desperate stand against their peculiar appearance, dubbing accounts of their straightness and duplication as sensational, whatever they may mean in such connection; for that they are both straight and double, as described, is certain,—a statement I make after having seen them, instead of before doing so, as is the case with the gifted objectors. Doubt, however, will not wholly cease till more people have seen them, which will not happen till the importance of atmosphere in the study of planetary detail is more generally appreciated than it is to-day. To look for the canals with a large instrument in poor air is like trying to read a page of fine print kept dancing before one's eyes, with the additional disadvantage that increase of magnification increases the motion. Advance in our study of other worlds depends upon choosing the very best atmospheric sites for our observatories.
It is interesting to recall, in connection with this incredulity about the canals, that precisely the same thing happened in the case of the discovery of Jupiter's satellites and with Huyghens' explanation of Saturn's ring. We are apt to imagine that our age of the world has a monopoly of skepticism. But this is a mistake. The spirit that denies has always been abroad; only in early days he was reputed to be the devil. II. MAP AND CATALOGUE
As we shall now have to call these Martian things by their names,—our names, that is,—it may be well to consider cursorily the nomenclature which has been evolved on the subject. Unfortunately, the planet has been quite too much benamed,—benamed, indeed, out of all recognition. There are no less than five or six systems current for its general topographical features. The result is that it has become something of a specialty just to know the names. The Syrtis Major, for example, appears under the following aliases: the Syrtis Major, the Mer du Sablier, the Kaiser Sea, the Northern Sea, to say nothing of translations of these, such as the Hourglass Sea; after which ample baptism it is a trifle disconcerting to have the sea turn out, apparently, not to be a sea at all. Everybody has tried his hand at naming the planet, first and last; naming a thing being man's nearest approach to creating it. Proctor made a chart of the planet, and named it thoroughly; Flammarion made another chart, and also named it thoroughly, but differently; Green drew a third map, and gave it a third set of names; Schiaparelli followed with a fourth, and furnished it with a brand-new set of his own; and finally W. H. Pickering found it necessary to give a few new names, just for particularization. To know, therefore, what part of the planet anybody means when he mentions it, one has to keep in his head enough names for five worlds. To cap which, it is to be remarked that not one of them is the thing's real—that is, its Martian—name, after all!
Fortunately, with the canals, matters are not so desperate, because so few people have seen them. Schiaparelli's monopoly of the sight pleasingly prevented, in their case, christening competition. What is more, he named them, very judiciously and most picturesquely, after mythologic river names. Where he got his names is another matter. Whether he started by being as learned in such lore as he afterward became may well be doubted. Certainly, one of the greatest discoveries made at Flagstaff has been the discovery of the meaning of Schiaparelli's names; some of them still defying the penetrating power of the ordinary encyclopaedia. Among them are classical mythologic ones of the class known only to that himself mythical character, Macaulay's every school boy; which speaks conclusively for their reconditeness. Others, I firmly believe, even that omniscient schoolboy can never have heard of. Want of space here precludes instances; but as a simple example I may say that the translation to Mars of the Phison and the Gihon, the two lost rivers of Mesopotamia, satisfactorily accounts for their not being found on earth by modern explorers.
With due mental reservation as to their meaning, I have adopted Schiaparelli's names, and, where it has been necessary to name newly discovered canals, have conformed as closely as possible to his general scheme. If, even in an instance or two, I have hit upon names that are incomprehensible, I shall feel that I have not disgraced my illustrious predecessor. For a brand-new thing no name is so good as one whose meaning nobody knows, except one that has no meaning at all. In that case the name not only is becoming but actually becomes the thing.
These names will be found affixed to their respective canals in the map at the end of the book, a map made upon what is called Mercator's projection. Mercator's projection I take to have been primarily an invention of the devil, although commonly credited to Mercator. It is not simple to construct and for popular purposes is eminently deceitful. It is intended for those at sea, whom we pray for on Sundays. It is certainly calculated to put any one entirely at sea who attempts to learn geography by means of it. Its object is to enable such as wish to do so to sail upon rhumb lines, a rhumb line upon a sphere being one which never changes its direction,—one, for example, which runs perpetually north-east one quarter east, or south half west. These lines, important in navigation, are in reality diminishing corkscrew-like spirals, but on this projection become straight lines which can be instantly laid down by rule and compass. To make such delineation possible it is necessary to distort the proportions of every part of the map, in increasing divergence toward the poles, with the lamentable result that in early life we all believed Nova Zembla to be a place as big as South America. Nevertheless Mercator's projection has certain advantages not so obvious to the uninitiated, nor requiring special mention here. In this connection it is only necessary to warn the reader, in the case of a geography with which he is not familiar, like that of Mars, to remember that the top and bottom of the map are drawn upon a scale three or four times as large as the middle; and, furthermore, that it is a consequence of Mercator's projection that arcs of great circles appear upon it, not as straight lines, but as curves always more or less concave to the equator. For relative size of the various features, he will find the twelve views from the globe accurate; but for the impressiveness of the great circle character of the canals, nothing short of a globe itself will give him adequate realization.
The map represents that part of the planet lying between latitudes 70° south and about 40° north. The south circumpolar regions will be found in the chart of the south pole facing page 84. The northern ones were not presented to view at the last opposition, owing to the tilt toward us of the Martian south pole. No canals, therefore, north of about 40° north latitude were visible.
The list of the canals detected at Flagstaff is as follows:
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The number of canals in this list is 183, and the number opposite each denotes the number of times each was seen and drawn; (Sus.) meaning, suspected in addition. There were in all, therefore, 3240 records made of them, not counting suspicions.
In the region visible at this opposition Schiaparelli has 79 canals. Of these 67 appear in the list given above. Of the other 12, the majority lie north of the equator, and therefore were likely not to be as visible as the rest at this last opposition, for two reasons connected with their position: first, on account of the tilt of the planet's axis at the time; and, secondly, because their northern situation would make their development late, as we shall shortly see. As no attempt was made to identify Schiaparelli's list, it will be seen how close is the accordance.
Of the 116 canals not down on Schiaparelli's map, 44 are canals in the dark regions and 72 canals in the light ones. Some of these, too, he saw prior to 1894. Both sets are, as a rule, more difficult of detection than the ones on his map; although there are some exceptions, attributable probably to difficulty of identification. The Brontes and Steropes, for example, might, unless well seen, be confounded with the Gigas on the one hand, or the Titan on the other. The most peculiar case, however, is the relative conspicuousness of the Ulysses.
III. ARTIFICIALITY.
It is patent that here are phenomena that are passing strange. To read their riddle we had best begin by excluding what they are not, as help towards deciphering what they are.
So far, we have regarded the canals only statically, so to speak; that is, we have sketched them as they would appear to any one who observed them in sufficiently steady air, once, and once only. But this is far from all that a systematic study of the lines will disclose. Before, however, entering upon this second phase of their description, we may pause to note how, even statically regarded, the aspect of the lines is enough to put to rest all the theories of purely natural causation that have so far been advanced to account for them. This negation is to be found in the supernaturally regular appearance of the system, upon three distinct counts: first, the straightness of the lines; second, their individually uniform width; and, third, their systematic radiation from special points.
On the first two counts we observe that the lines exceed in regularity any ordinary regularity of purely natural contrivance. Physical processes never, so far as we know, end in producing perfectly regular results; that is, results in which irregularity is not also discernible. Disagreement amid conformity is the inevitable outcome of the many factors simultaneously at work. From the orbits of the heavenly bodies to phyllotaxis and human features, this diversity in uniformity is apparent. As a rule, the divergences, though small, are quite perceptible; that is, the lack of absolute uniformity is comparable to the uniformity itself, and not of the negligible second order of unimportance. In fact, it is by the very presence of uniformity and precision that we suspect things of artificiality. It was the mathematical shape of the Ohio mounds that suggested mound-builders; and so with the thousand objects of every-day life. Too great regularity is in itself the most suspicious of circumstances that some finite intelligence has been at work.
If it be asked how, in the case of a body so far off as Mars, we can assert sufficient precision to imply artificiality, the answer is twofold: first, that the better we see these lines, the more regular they look; and, second, that the eye is quicker to perceive irregularity than we commonly note. It is indeed surprising to find what small irregularities will shock the eye.
The third count is, if possible, yet more conclusive. That the lines form a system; that, instead of running any whither, they join certain points to certain others, making thus, not a simple network, but one whose meshes connect centres directly with one another,—is striking at first sight, and loses none of its peculiarity on second thought. For the intrinsic improbability of such a state of things arising from purely natural causes becomes evident on a moment's consideration.
If lines be drawn haphazard over the surface of a globe, the chances are ever so many to one against more than two lines crossing each other at any point. Simple crossings of two lines will of course be common in proportion to the sum of an arithmetical progression; but that any three lines should contrive to cross at the same point would be a coincidence whose improbability only a mathematician can properly appreciate, so very great is it. If the lines were true lines, without breadth, the chances against such a coincidence would be infinite, that is, it would never happen; and, even had the lines some breadth, the chances would be great against a rendezvous. In other words, we might search in vain for a single instance of such encounter. On the surface of Mars, however, instead of searching in vain, we find the thing occurring passim; this a priori most improbable rendezvousing proving the rule, not the exception. Of the crossings that are best seen, all are meeting-places for more than two canals.
To any one who had not seen the canals, it might occur that something of the same improbability would be fulfilled by cracks radiating from centres of explosion or fissure. But such a supposition is at once negatived by the uniform breadth of the lines, a uniformity impossible in cracks, whose very mode of production necessitates their being bigger at one end than at the other. We see examples of what might result from such action in the cracks that radiate from Tycho, in the Moon, or, as we now know from Professor W. H. Pickering's observations, from the craterlets about it. These cracks bear no resemblance whatever to the lines on Mars. They look like cracks; the lines on Mars do not. Indeed, it is safe to say that the Martian lines would never so much as suggest cracks to any one. Lastly, the different radiations fit into one another absolutely, an utter impossibility were they radiating rifts from different centres.
In the same way we may, while we are about it, show that the lines cannot be several other things which they have more or less gratuitously been taken to be. They cannot, for example, be rivers; for rivers could not be so obligingly of the same size at source and mouth, nor would they run from preference on arcs of great circles. To do so, practically invariably, would imply a devotion to pure mathematics not common in rivers. They may, in some few instances, be rectified rivers, which is quite another matter. Glaciation cracks are equally out of the question,—first, for the causes above mentioned touching cracks in general; and, second, because there is, unfortunately, no ice where they occur. Nor can the lines be furrows ploughed by meteorites,—another ingenious suggestion,—since, in order to plough, invariably, a furrow straight from one centre to another, without either missing the mark or overshooting it, the visitant meteorite would have to be specially trained to the business.
Such are the chief purely natural theories of the lines, excluding the idea of canals,—theories advanced by persons who have not seen them. No one who has seen the lines well could advance them, inasmuch as they are not only disproved by consideration of the character of the lines, but instantly confuted by the mere look of them.
Schiaparelli supposes the canals to be canals, but of geologic construction. He suggests, however, no explanation of how this is possible; so that the suggestion is not, properly speaking, a theory. That eminent astronomer further says of the idea that they are the work of intelligent beings: "Io mi guarderò bene dal combattere questa supposizione, la quale nulla include d'impossibile." (I should carefully refrain from combating this supposition, which involves no impossibility.) In truth, no natural theory has yet been advanced which will explain these lines.
Their very aspect is such as to defy natural explanation, and to hint that in them we are regarding something other than the outcome of purely natural causes. Indeed, such is the first impression upon getting a good view of them. How instant this inference is becomes patent from the way in which drawings of the canals are received by incredulously disposed persons. The straightness of the lines is unhesitatingly attributed to the draughtsman. Now this is a very telling point. For it is a case of the double-edged sword. Accusation of design, if it prove not to be due to the draughtsman, devolves ipso facto upon the canals.
IV. DEVELOPMENT
We have thus far considered the aspect of the canals viewed at any one time. We have now to consider an even more interesting branch of the subject, their consecutive appearances. The "open sesame" to our comprehension of the physical condition of Mars lies in systematic study of the appearances the planet's surface presents night after night and month after month. For that surface changes; and the order, extent, and character of its changes contain the key to their explanation. True as this is of the larger markings upon the disk, it is if anything more noticeably the case with the finer detail of the canals.
After the fundamental fact that such curious phenomena as the canals are visible, is the scarcely less curious one that they are not always so. At times the canals are invisible, and this invisibility is real, not apparent; that is, it is not an invisibility due to distance or obscuration of any kind between us and them, but an actual invisibility due to the condition of the canal itself. With our present optical means, at certain seasons they cease to exist. For aught we can see, they simply are not there.
That distance is not responsible for the disappearance of the canals is shown by their relative conspicuousness at different times. It is not always when Mars is nearest to us that the canals are best seen. On the contrary, their visibility bears no relation to proximity. This is evidenced both by the changes in appearance of any one canal and by the changes in relative conspicuousness of different canals. Some instances of the metamorphosis will reveal this conclusively. For example, during the end of August and the beginning of September, at this last opposition, the canals about the Lake of the Sun were conspicuous, while the canals to the north of them were almost invisible. In November the relative intensities of the two sets had distinctly changed: the southern canals were much as before, but the northern ones had most perceptibly darkened.
Another instance of the same thing was shown in the case of the canals to the north of the Sinus Titanum when compared with those about the Solis Lacus. In August the former were but faintly visible; in November they had become evident; and yet, during this interval, little change in conspicuousness had taken place in the canals in the Solis Lacus region.
With like disregard of the effect due to distance, the canals to the east of the Ganges showed better at the November presentation[1] of that region than they had at the October one, although the planet was actually farther off at the later date, in the proportion of 21 to 18.
A more striking instance of the irrelevancy of distance in the matter was observed in the same region by Schiaparelli in 1877. It is additionally interesting as practically dating his discovery of the canals. In early October of that year, on the evenings of the 2d and the 4th, he tells us, under excellent definition, and with the diameter of the planet's disk 21" of arc, the continental region between the Pearl-Bearing Gulf and the Bay of the Dawn was quite uniformly, nakedly bright, and destitute of suspicion of markings of any sort. A like state of things was the case with the same region at its next presentation, on the 7th of November. Four months later, when the diameter of the disk had been reduced by distance to 5".7, or, in other words, when the planet had receded to four times its previous distance from the earth, the canal called the Indus appeared, perfectly visible, in the region mentioned. At the next opposition, in 1881, similar effects occurred; the canals in this region remaining obstinately invisible while the planet was near the earth, and then coming out conspicuously when it had gone farther away. Distance, therefore, is not, with the canals, the great obliterator.
As to their veiling by Martian cloud or mist, there is no evidence of any such obscuration. The coast line of the dark areas appears as clear-cut when the canals are invisible as when they become conspicuous.
A canal, then, alters in visibility for some reason connected with itself. It grows into recognition from intrinsic cause. But, during all its metamorphoses, in one thing, and in one thing only, it remains fixed,—in position. Temporary in appearance, the canals are apparently permanent in place. Not only do they not change in position during one opposition; they seem not to do so from one opposition to another. The canals I have observed this year agree fairly within the errors of observation with those figured on Schiaparelli's chart.
The fact that in all cases they do not absolutely agree with his is the very best of proofs that they are substantially the same; for such slight discordance proves the absence of conscious psychic reproduction. It confirms by not conforming.
As, in observations of minute detail, the psychic element insensibly creeps in, it will be well to consider it for a moment. An idea is a force, a mode of motion, which, unless obstructed by other ideas, instantly and inevitably produces its effect upon whatever mind it may chance to impinge, just as light or electricity or any other mode of motion does, according to its kind. An easy instance of this can be got by asserting at dinner, before a company of connoisseurs, that the wine is slightly corked. Every one not actuated by a spirit of contradiction will at once perceive that it is so, and will continue to believe it, in many cases, after it is abundantly disproved. This is what takes place in the normal, unbiased—that is, so far as this idea goes—vacant mind. But minds have their familiar ideas, which an incoming idea is pretty sure to rouse, and these react to some extent upon the stranger, and color it with something of their own complexion. If we expect to meet a certain person, an approaching figure will most deceitfully take on his garb. The mere idea of a man walking finds the expectation ready instinctively to endow it with the attributes of our friend. But this may happen truly as well as falsely. The expert sees what the tyro misses, not from better eyesight but from better mechanism in the higher centres. A very slight hint from the eye goes a long way in the brain of the one; no distance at all in the brain of the other.
Our senses are our avenues of approach from the outer world. Messages from them are therefore usually and rightly attributed to stimuli from without. But it is possible for these messages to be tampered with at any stage of their journey. It is even possible for them to be started in some other part of the brain, travel down to the lower centres and be sent up from them to the higher ones, indistinguishable from bona fide messages from without. Bright points in the sky or a blow on the head will equally cause one to see stars. In the first case the eyes were duly affected from without; in the second, the nerves were tapped to the same effect in mid-route; but in each case the subsequent current travels to the higher centres apparently as authentic the one as the other.
Hallucinations of one sort and another occur in this way. More common, however, are unconscious changes in an originally quite veridic message. We easily see what we expect to see, but with great difficulty what we do not. This may be due to individual idiosyncrasy, or it may be due to a prevailing idea of the time, affecting people generally, in which we unwittingly share. Fashion is as potent here as elsewhere. The very same cause will show us at one time what we remain callously blind to at another. A few years ago it was the fashion not to see the canals of Mars, and nobody except Schiaparelli did. Now the fashion has begun to set the other way, and we are beginning to have presented suspiciously accurate fac-similes of Schiaparelli's observations.
In any observation, the observer is likely to be unconsciously affected in some way or other pro or con, which, from the fact that he is unconscious of it, he is unable to find out. The only sure test, therefore, is the seeing what no one else has seen, the discovery of new detail. Next to that is not too close an agreement with others. Inevitable errors of observation, to say nothing of times and seasons, distance and tilt, are certain to produce differences, of which one has ample proof in comparing his own drawings with one another. Even too close agreement with one's self is suspicious. In the matter of fine detail, absolute agreement is therefore neither to be expected nor to be desired.
All the changes so far observed on the planet's disk are, I believe, capable of explanation either by errors of observation or by seasonal change. For, as is the case with the Earth, not only must vegetation produce different appearances according to the time of year, but its aspects would vary somewhat as between year and year. This seasonal variation would affect not only the visibility of any one canal at any particular time, but might easily produce apparent alterations of place; visibility of one canal, combined with visibility or invisibility in its neighbors, being competent to simulate any shift.
The Araxes is a case in point. On Schiaparelli's chart there is but one original Araxes and one great and only Phasis. But it turns out that these do not possess the land all to themselves. No less than five canals traversing the region, including the Phasis itself, were visible this year at Flagstaff, and I have no doubt there are plenty of others waiting to be discovered. These cross one another, at all sorts of angles. Unconscious combination of them is quite competent to give a turn to the Araxes one way or the other, and make it curved or straight at pleasure.
Unchangeable, apparently, in position, the canals are otherwise among the most changeable features of the Martian disk. From being invisible, they emerge gradually, for some reason inherent in themselves, into conspicuousness. In short, phenomenally at least, they grow. The order of their coming carries with it a presumption of cause, for it synchronizes with the change in the Martian seasons. Their first appearance is a matter of the Martian time of year.
To start with, the visible development of the canal system follows the melting of the polar snows. Not until such melting has progressed pretty far do any of the canals, it would seem, become perceptible.
Secondly, when they do appear, it is, in the case of the southern hemisphere, the most southern ones that become visible first. Last June, when the canals were first seen, those about the Lake of the Sun and the Phoenix Lake were easier to make out than any of the others. Now, this region is the part of the reddish-ochre continent, as we may call it, that lies nearest the south pole. It extends into the blue-green regions as far south as 40 of south latitude. Nor do any so-called islands—that is, smaller reddish-ochre areas—stand between it and the pole. It lies first exposed, therefore, to any water descending toward the equator from the melting of the polar cap.
Having once become visible, these canal remained so, becoming more and more Plate XIX
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LACUS PHOENICIS
November, 1894
The order in which the canals came out hinted that two factors were operative to the result,—latitude and proximity to the dark regions. Other things equal, the most southern ones showed first; beginning with the Solis Lacus region, and continuing with those about the Sea of the Sirens and the Titan Gulf, and so northward down the disk. Other things were not, however, always equal in the way of topographical position. Notably was this the case with the areas to the west of the Syrtis Major, which developed canals earlier than their latitudes would warrant. Now, to the Syrtis Major descend from the pole the great straits spoken of before, which, although not in their entirety water, are probably lands fertilized by a thread of water running through them. They connect the polar sea with the Syrtis Major in a tolerably straight line.
The direction of the canal also affects its time of appearance, though to a less extent. Canals running north and south, such as the Gorgon, the Titan, the Brontes, and the like, became visible, as a rule, before those running east and west. Especially was this noticeable in the more northern portions of the disk. Time of appearance was evidently a question of latitude tempered by ease of communication.
After the canals had appeared, their relative intensities changed with time, and the change followed the same order in which the initial change from invisibility to visibility had taken place. A like metamorphosis happened to each in turn from south to north, in accordance with, and continuance of, the seasonal change that affected all the blue-green areas.
To account for these phenomena, the explanation that at once suggests itself is, that a direct transference of water takes place over the face of the planet, and that the canals are so many waterways. This explanation labors under the difficulty of explaining nothing. There are two other objections to it: an insufficiency of water, and a superabundance of time, for some months elapsed between the apparent departure of the water from the pole and its apparent advent in the equatorial regions; furthermore, each canal did not darken all at once, but gradually. We must therefore seek some explanation which accounts for this delay. Now, when we do so, we find that the explanation advanced above for the blue-green areas explains also the canals, namely, that what we see in both is, not water, but vegetation; for if the darkening be due to vegetation, time must elapse between the advent of the water and its perceptible effects,—time sufficient for the flora to sprout. If, therefore, we suppose what we call a canal to be, not the canal proper, but the vegetation along its banks, the observed phenomena stand accounted for. This suggestion was first made some years ago by Professor W. H. Pickering.
That what we see is not the canal proper, but the line of land it irrigates, disposes incidentally of the difficulty of conceiving a canal several miles wide. On the other hand, a narrow, fertilized strip of country is what we should expect to find; for, as we have seen, the general physical condition of the planet leads us to the conception, not of canals constructed for waterways,—like our Suez Canal,—but of canals dug for irrigation purposes. We cannot, of course, be sure that such is their character, appearances being often highly deceitful; we can only say that, so far, the supposition best explains what we see. Further details of their development point to this same conclusion.
In emerging from invisibility into evidence, the canals first make themselves suspected, rather than seen, as broad, faint streaks smooching the disk. Such effect, however, seems to be an optical illusion, due to poor air and the difficulty inherent in detecting fine detail; for on improvement in the seeing I have observed these broad streaks contract to fine lines, not sensibly different in width from what they eventually become.
The parts of the canals which are nearest the dark areas show first, the line extending sometimes for a few hundred miles into the continent, sometimes for a thousand or more; then, in course of time, the canal becomes evident in its entirety. Complete visibility takes place soon after the canal has once begun to show, although it show but faintly throughout.
This tendency to being seen in toto is more strikingly displayed after a canal has attained its development. It is then not commonly seen in part. Either it is not seen at all, owing to the seeing not being good enough, or it is visible throughout its length from one junction to another.
Apart from their extension, the growth of the canals consists chiefly in depth of tint. They darken rather than broaden,—a fact which tends to corroborate their vegetal character; for that long tracts of country should be thus simultaneously flooded all over to a gradually deepening extent is highly unlikely, while a growth of vegetation would deepen in appearance in precisely the way in which the darkening takes place.
As for color, the lines would seem to be of the same tint as the blue-green areas. But, owing to their narrowness, this is only an inference. I have never chanced to see them of distinctive color.
At this point it is probable that a certain obstacle to such wholesale construction of canals, however, will arise in the mind of the reader, namely, the thought of mountains; for mountains are by nature antagonistic to canals. Only the Czar of all the Russias—if we are to credit the account of the building of the Moscow railway—would be capable of running a canal regardless of topography. Nor will the doings at our own antipodes help us to conceive such construction; for though the Japanese irrigate hillsides, the water in the case comes from slopes higher yet, whereas on Mars it does not.
Indeed, for the lines to contain canals we must suppose either that mountains prove no obstacles to the Martians, or else that there are practically no mountains on Mars. For the system seems sublimely superior to possible obstructions in the way; the lines running, apparently, not where they may, but where they choose. The Eumenides-Orcus, for example, pursues the even tenor of its unswerving course for nearly 3500 miles. Now, it might be possible so to select one's country that one canal should be able to do this; but that every canal should be straight, and many of them fairly comparable with the Eumenides-Orcus in length, seems to be beyond the possibility of contrivance.
In this dilemma between mountains on the one hand and canals on the other, a certain class of observations most opportunely comes to our aid; for, from observations which have nothing to do with the lines, it turns out that the surface of the planet is, in truth, most surprisingly flat. How this is known will most easily be understood from a word or two upon the manner in which astronomers have learnt the height of the mountains in the Moon.
The heights of the lunar mountains are found from measuring the lengths of the shadows they cast. As the Moon makes her circuit of the Earth, a varying amount of her illuminated surface is presented to our view. From a slender sickle she grows to full moon, and then diminishes again to a crescent. The illuminated portion is bounded by a semicircle on the one side, and by a semi-ellipse on the other. The semi-circle is called her limb, the semi-ellipse her terminator. The former is the edge we see because we can see no farther; the latter, the line upon her surface where the sun is just rising or setting. Now, as we know, the shadows cast at sunrise or sunset are very long, much longer than the objects that cast them are high. This is due to the obliquity at which the light strikes them; the same effect being produced by any sufficiently oblique light, such as an electric light at a distance. Imperceptible in themselves, the heights become perceptible by their shadows. A road illuminated by a distant arc light gives us a startling instance of this; the smooth surface taking on from its shadows the look of a ploughed field.
It is this indirect kind of magnification that enables astronomers to measure the lunar mountains, and even renders such vicariously visible to the naked eye. Every one has noticed how ragged and irregular the inner edge of the Moon looks, while her outer edge seems perfectly smooth. In one place it will appear to project beyond the perfect ellipse, in another to recede from it. The first effect is due to mountain tops catching the sun's rays before the plains about them; the other, to mountain tops further advanced into the lunar day, whose shadows still shroud the valleys at their feet. Yet the elevations and depressions thus rendered so noticeable vanish in profile on the limb.
Much as we see the Moon with the naked eye do we see Mars with the telescope. Mars being outside of us with regard to the Sun, we never see him less than half illumined, but we do see him with a disk that lacks of being round,—about what the Moon shows us when two days off from full. It is when he is in quadrature—that is, a quarter way round the celestial circle from the Sun—that he shows thus, and we see him then with the telescope at closer range than we ever see the Moon without it. So observed we notice at once that his terminator, or inner edge, presents a very different appearance from the lunar one. Instead of looking like a saw, it looks comparatively smooth, like a knife. From this we know that, relatively to his size, he has no elevations or depressions upon his surface comparable to the lunar peaks and craters.
His terminator, however, is not absolutely perfect. Irregularities are to be detected in it, although much less pronounced than those of the Moon. His irregularities are of two kinds. The first, and by all odds the commonest phenomenon, consists in showing himself on occasions surprisingly flat; not in this case an inferable flatness, but a perfectly apparent one. In other words, his terminator does not show as a semi-ellipse, but as an irregular polygon. It looks as if in places the rind had been pared off. The peel thus taken from him, so to speak, is from twenty to forty degrees wide, according to the particular part of his surface that shows upon the terminator at the time.
Plate XX
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TERMINATOR VIEWS
By Prof. W. H. Pickering
August 24, 1894
A series of unusually marked elevations and depressions upon the terminator at the above hours
Plate XXI
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| Fig. I. Nov. 26. Long. cent. 314°
Seeing 2 to 6. Diam. 15".8 |
Fig. II. Oct. 9. Long. cent. 45°
Seeing 5 to 9. Diam. 21". 7 | |
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| Fig. III. Feb. 8. Long. cent. 295°
Seeing 2 to 5. Diam. 7".5 |
Fig. IV. Nov. 23. Long. cent. 31°
Seeing 2 to 7. Diam. 16".3 | |
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| Fig. V. March 16. Long. cent. 312°
Seeing 2 to 8. Diam. 6".4 |
Fig. VI. March 9. Long. cent. 26°
Seeing 3 to 7. Diam. 6" .6 |
DRAWINGS AFTER OPPOSITION [EXCEPT ONE]
By A. E. DOUGLASS
Plate XXII
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| Fig. I. Nov. 14. Long. cent. 114°
Seeing 4 to 8. Diam. 17".9 |
Fig. II. Nov. 5. Long. cent. 184°
Seeing 1 to 3. Diam. 19".5 | |
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| Fig. III. Dec 17. Long. cent. 100°
Seeing 2 to 6. Diam. 12".4 |
Fig. IV. Dec. 1. Long. cent. 246°
Seeing 2 to 4. Diam. 14".9 | |
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| Fig. V. Feb. 21. Long. cent. 193°
Seeing 2 to 4. Diam. 7".4 |
Fig. VI. Jan. 8. Long. cent. 266°
Seeing 1 to 3. Diam. 9".9 |
DRAWINGS AFTER OPPOSITION
By A. E. Douglass
Finally, some of the most southern appear to run tolerably straight toward the pole; but of the plan underlying the whole system of Martian canals we cannot at present predicate details, as, though the system instantly suggests plan, it suggests a plan that does not instantly commend itself to human comprehension.
Mr. Douglass finds 44 of these canals, not including the straits between the islands, as is shown in the following list:—
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All these run either through the dark regions proper, or through those chiaro-oscuro areas, such as Deucalionis Regio and Pyrrhae Regio, which have hitherto been thought to be amphibious, and are probably half desert. They connect on the one hand with the canals in the bright regions, and on the other with the straits between the so-called islands,—such strait-canals as Scamander, Xanthus, and the like, if we may so designate without misunderstanding what is probably not water at all.
It is interesting thus to forestall objection about a missing link by discovering that link thus early.
Before passing on to certain other phenomena connected with the canals of like significance, we may note here an obiter dictum of the irrigation theory of some slight corroborative worth; for, if a theory be correct, it will not only fit all the facts, but at times go out of its way to answer questions. Such the present one seems to do. If the seas be seas, and the canals canals, we stand confronted by the problem how to make fresh-water canals flow out of salt-water seas. General considerations warrant us in believing that the Martian seas, like our own, would contain salts in solution, while irrigation ditches, there as here, should flow fresh water to be most effective, and we seem committed to the erection of distilleries upon a gigantic scale. But if, on the contrary, the seas be not seas, but areas of vegetation, the difficulty vanishes at once; for, if the planet be dependent upon the melting of its polar snows for its spring freshet, the water thus produced must necessarily be fresh, and the canals be directly provided with the water they want. The polar sea is a temporary body of water, formed anew each year, not a permanent ocean; consequently there is no chance for saline matter to collect in it. From it, therefore, fresh water flows, and, like our rivers, gathers nothing to speak of in the way of salt before it is drawn off into the canals.
We now come to some phenomena connected with the canals, of the utmost suggestiveness. I have said that the junctions held, in a twofold way, the key to the unlocking of the mystery of the canals: in the first place, in the fact that such junctions exist. The second and more important reason remains to be given, for it consists in what we find at those junctions. This we shall see in the next chapter.
- ↑ A presentation of any part of the planet is the occasion when that part of the disk is turned toward the observer. Many causes combine to make the face presented each night vary, but the chief one is that the Earth rotates about forty-one minutes faster than Mars, and consequently gains a little less than ten degrees on him daily. After about thirty-seven days, therefore, the two planets again present the same face to each other at the same hour.