XIII
VARIETY OF CONDITIONS UNDER WHICH LIFE EXISTS

Not only does life but intelligence flourish on this globe under a great variety of conditions, as regards temperature and surroundings, and no sound reason can be shown why under certain conditions which are frequent in the universe, intelligent beings should not acquire the highest development.

Simon Newcomb.

The argument most often urged against the idea that life exists in Mars is that there is no atmosphere in that planet, or if there is one it is so rarefied that it could not sustain life as we know it. According to Proctor, we have heretofore been led to consider the planet's physical condition as adapted to the wants of creatures which exist upon our own Earth rather than to ascertain the conditions which might obtain to enable life to exist on the surface of other planets. It is highly probable that if an air-breathing animal of our earth were instantly immersed in an atmosphere as rare as that of Mars, it would perish in a short time. Precisely what a species through thousands of generations of selection and survival might adapt itself to, is an open question. Leaving this contention for a moment, let us consider the almost infinite variety of conditions under which life exists on our globe, and we shall find that any and all conditions which the surface of Mars may offer, if experienced gradually through successive generations, would not be inimical to terrestrial life from the lowest to the highest, including even man.

Mr. Garrett P. Serviss, in discussing the question of life, in his book "Other Worlds," said: "Would it not be unreasonable to assume that vital phenomena on other planets must be subject to exactly the same limitations that we find circumscribing them in our world? That kind of assumption has more than once led us far astray even in dealing with terrestrial conditions. It is not so long ago, for instance, since life in the depths of the sea was deemed to be demonstrably impossible. The bottom of the ocean, we were assured, was a region of eternal darkness and of frightful pressure, wherein no living creatures could exist. Yet the first dip of the deep-sea trawl brought up animals of marvellous delicacy of organization, which, although curiously and wonderfully adapted to live in a compressed liquid, collapsed when lifted into a lighter medium."

One has only to make himself familiar with the wide range of conditions under which life in various forms exists on the Earth, to realize that the introduction of Martian conditions here would not be such an overwhelming calamity, and if these conditions could be introduced by minute increments covering thousands of centuries, it is not unreasonable to believe that myriads of forms would survive the change, and among those that survive would be precisely the kinds that thrive under the most diverse conditions here​—​namely, man and the higher hymenoptera, the ants.

To enumerate, in the broadest way, the variety of conditions under which life exists here, one has only to enumerate creatures living in the deepest abysses of the ocean; high up on the slopes of the Himalayas; swarming in arctic seas; withstanding the hot glare of a tropical sun; living deep in the ground; breeding in the darkest caves; flourishing in desert regions; thriving in water below freezing, and again in water nearly at the boiling point. Professor Jeffries Wyman, in a memoir on "Living Organisms in Heated Water," has collected data showing that fishes are found living in water ranging from 104° to 135° Fahrenheit. He also found that low forms of plant life exist in water of various temperatures as high as:

If we consider man alone, we find him at Aden, on the Red Sea, at a temperature of 130° in the shade, and in Siberia at 70° below zero; grovelling in mines deep in the Earth, and living in great communities ten thousand feet above sea-level; fighting battles on the slopes of the Himalayas, at an altitude of 19,000 feet; nomadic on sterile tracts; sweltering under the glaring sun of the equator, and existing in regions of perpetual snow and ice, and without sunlight for six months of the year. Such are a few of the varied conditions to which man has become accustomed since he emerged from his tropical and arboreal relatives.

The question finally comes down to the effect of the rarefaction of air on life. An inquiry as to how far man can stand changes of atmospheric pressure is of interest in this connection, for we know that sudden changes are accompanied by mountain sickness, at great elevations, and caisson disease under great pressure. Large birds soar among the high peaks of the Andes and drop at once to sea-level. I have dredged delicate mollusks at a depth of one hundred and fifty fathoms of water and kept them alive for weeks in an aquarium. Man, while showing a sensitiveness to changes in barometric pressure when experienced suddenly, can nevertheless get accustomed to great ranges of pressure. The cities of Bogota and Quito are 10,000 feet above the level of the sea and yet in Quito when De Saussure, the naturalist, became so ill from the rarefaction that he could hardly find energy enough to read his instruments, and his servants, digging holes in the snow, fainted from the exertion, the natives were pursuing their various activities, and bull-fights were going on! One has only to read the accounts of the English expedition to Thibet to learn that troops fought in skirmishes at the height of 19,000 feet.

Mr. Douglas W. Freshfield (in "Scot. Geo. Mag.," April, 1905) gives an account of mountain sickness in the Sikkim Himalaya. He says the effect of high altitude was different in different individuals; some men were entirely free from it, and among them a Goorkha, who ran back in a pass at an altitude of 20,000 feet to hurry up some loiterers. Another member of the party, an Englishman, actually gained in weight, and had an increased appetite. Here, then, are a few men among a small number, without previous experience in rarefied air, feeling no disturbance, and, in one case, actually benefited by it!

The question arises as to what natural selection would do among a hundred million say, who, through many centuries, might be subject to a gradual attenuation of the air. The result of rarefaction of the atmosphere and the absence of moisture is associated with marked hygienic influences. The Hadley Climatological Laboratory of the University of New Mexico has made special investigations as to the increased lung capacity of those living at high altitudes, the relation of dry soil to health, etc. Important work has been done by Drs. John Weinzirl, C. Edw. Magnusson, F. S. Maltby, and Mrs. W. C. Hadley, and their investigations go to prove that high altitudes and absence of moisture are favorable to the health of man on this world, and by analogy would not be inimical to the survival of certain forms of life in Mars.

Dr. S. E. Solby (in "Medical Climatology," p. 43, 1897), in describing the effects of rarefaction of the air says: "The amount of air taken in at each breath becomes greater, and the air-cells, many of which are at lower altitudes often unused, are dilated."

If we consider the atmospheric pressure under which a man can work and live, we find equal adaptability.

Mr. Gardner D. Hiscox, in his work on "Compressed Air, Its Production, Uses, and Applications," says: "Experience has taught that the ill effects are in proportion to the rapidity with which the transmission is made from compressed air to the normal atmosphere. That while the pressure remains stationary all subjective phenomena disappear." He speaks of pressure of forty or fifty pounds to the square inch, and says that, at these pressures, taste, smell, and the sense of touch lose their acuteness.

In the "Engineering Record" for January 23, 1904, there is an interesting article on "Caisson Disease." It says that twenty pounds pressure per square inch is common on foundation work in New York, and that bridge piers have been built when pressures of nearly fifty pounds were required. The deepest pneumatic work in New York was done in the East River gas tunnel, when the maximum pressure was about forty-seven to fifty pounds per square inch above atmospheric. In the gas tunnel four men died from the effects of heavy pressure, while none died from that reason under bridge work. The article further says that ordinarily "strong young men in proper condition do not suffer from working two four-hour shifts daily, under pressure up to twenty-five or thirty pounds; above that limit injurious effects may be felt," etc.

Let any reasonable man consider the meaning of these data. Without any selective action on the race, without even a graded increase of pressure from boyhood up, these workmen perform hard labor of stone excavation at these pressures, and in the same way, without previous experience, men are fighting battles at 19,000 feet altitude, and in one instance growing fat at 20,000 feet. Eminent German and French scientists have studied the effects of pneumatic pressure by numerous experiments on men and animals. One experimenter subjected a great number of dogs, cats, rabbits, guinea-pigs, and other animals to repeated pressures up to one hundred pounds, and carefully observed the effects of the varying conditions, some of which were fatal, while others were apparently harmless. The experiments showed that sudden release from heavy pressures was fatal, but that if three or four hours were occupied in reducing a pressure of one hundred pounds, it was harmless.

With these facts one cannot help wondering whether even man himself could not exist on Mars if allowed time to get accustomed to the rare atmosphere through thousands of generations of minute increments of adaptation.

As a matter of fact we use but a small portion of our lung capacity. Let any one experiment with himself and observe that after he has inspired the accustomed quantity of air he can continue for some time to inspire more air, and also when he has expired the accustomed quantity of air in normal breathing, he can continue to expire a great deal more air. Professor Jeffries Wyman, the famous lecturer on comparative anatomy at Harvard, used to tell us that we ordinarily inspired about twenty cubic inches of air but we could inspire one hundred cubic inches more by an effort; also that having expired the ordinary quantity we could expire a hundred cubic inches more and when the lungs were removed from the body, an extra hundred cubic inches could be forced from them. A surgeon friend tells me that many men live and work with the greater portion of both lungs diseased, and unable to perform their functions.

It would be an interesting inquiry to ascertain what other species of the animal kingdom has so wide a range as man. The dog evidently follows him in all altitudes and at all temperatures.

The group of insects to which the bees, wasps, and ants belong, have always been recognized as standing highest in intelligence among the invertebrates. In the great work of Dr. and Mrs. Peckham on wasps are shown manifestations of intelligence among the wasps that are simply startling, and the remarkable work of Miss Adele M. Fielde on the ants adds greatly to the evidences of their unique intelligence. The ant stands among the invertebrates much as man does among the vertebrates. One has only to state concretely that ants practise a division of labor; distinguish certain colors; estimate numbers; recognize friends and enemies; harvest seeds, and, it is said, raise them, hence are called agricultural ants; have insect cows and milk them; collect leaves which they chop up for the purpose of raising a kind of fungus upon which they live; organize raids and fight battles in masses; enslave other species; build covered ways and tunnels; and perform other acts of a similar nature.

Bearing these statements in mind it is an interesting fact that at altitudes in Arizona, where man finds it impossible to live except by fetching water from regions below, the ant, equally dependent on water, has survived on these high tablelands, and manages to raise huge colonies. In wandering over the mesa at Flagstaff, at an elevation of over 7,000 feet, the extreme dryness of the ground is indicated by long cracks which appear on the surface. Here, where hardly any insect is found except an occasional roaming butterfly, the ant has survived and is met with in great numbers. Even a rare solitary insect known as the velvet ant, and consequently without communal aid, is found chirping merrily amidst these arid surroundings.

In this connection, it is interesting to observe that creatures endowed with the highest intelligence, both vertebrate and invertebrate, manage to survive in considerable numbers in regions devoid of water. One conveys it to his habitations from lower levels, the other digs wells or manages to utilize the moisture from the roots of trees.

XIV
MY OWN WORK

Snow caps of solid carbonic acid gas, a planet cracked in a positively monomaniacal manner meteors ploughing tracks across its surface with such mathematical precision that they must have been educated to the performance, and so forth and so on, in hypotheses each more astounding than its predecessor, commend themselves to man, if only by such means he may escape the admission of anything approaching his kind.

Percival Lowell.

I am led to present these few brief memoranda of my own work in order to meet questions which would naturally be asked as to whether I had ever seen Mars through a telescope, and if so did I make out any markings or canals.

It was my good fortune to have the privilege of observing Mars every night at the Lowell Observatory (see Plate VII) for thirty-four days, covering an almost complete presentation of the planet. A few nights were cloudy and no observations were made. With these exceptions I was in the observer's chair several times each evening. The twenty-four inch refractor of which I had the use was the last telescope Clark ever made, and he pronounced it his best one. This instrument (Plate VIII) is mounted on a mesa near the town of Flagstaff, Arizona, at a height of over 7,000 feet above sea-level, in an atmosphere of remarkable clarity and steadiness. I have already stated on page 80 my first experiences in observing and will only present the brief notes I made at the time of observation. Better results would have accompanied these efforts had I followed the custom of Michael Faraday and asked what was I to look at, what was I expected to see? I had been somewhat prejudiced as to the existence of the canals by the comments of sporadic observers, many of whom, by the way, had never been able to see them, and denying that any one else ever had, straightway proceeded to suggest a theory to explain their presence! Careful to avoid any bias in the matter I rigidly refused to allow either Professor Lowell or his assistants to suggest where I might find a canal or a marking on the disk. The night before I left the Observatory for home I asked Mr. Lowell for the first time, to indicate the position of some conspicuous canal which I had not seen. This he did and examining the region which I supposed he had indicated on the disk I searched in vain for the line. In doing so another line was detected and drawn, and on confessing my failure to see the line he had described, showed him my drawing, when he exclaimed, "Why, you have got it," and sure enough when he showed me his drawing and repeated the directions he had given me, I found that I had been looking at the wrong pole of the planet.

In one stage of great discouragement I came across a statement made by Mr. A. Stanley Williams which has already been quoted, namely, that he had to observe continually for two months before sufficient sensitiveness enabled him to make out the more delicate markings. That I might have seen more had I been acclimated, and had been accustomed to telescopic observation there is no doubt. The record is poor enough and yet under the conditions mentioned the results may be of interest to the reader.

On Plate IX I give a few of my drawings of Mars in which are indicated the lines I saw many times and was able to fix. Other lines flashed out for an instant but these were not recorded, simply because I could not definitely locate them.

The expression "poor seeing" in the above notes must be taken in a comparative sense with relation to the usual conditions of the atmosphere of Flagstaff. Poor seeing, therefore, at Flagstaff would be equal, if not superior, to the best seeing at much lower levels. An astronomer who resigned his position in a western observatory for duties at Mount Wilson, California, told me that for thirty consecutive nights the seeing was superior to the best nights he had observed in at his former post.

XV
WHAT THE MARTIANS MIGHT SAY OF US

O wad some power the giftie gie us,
To see oursels as others see us!

Robert Burns.

For every single perplexity of interpretation we encounter in our study of the surface markings of Mars, the Martian would encounter a dozen perplexities in interpreting the various features on the surface of the Earth.

Admitting the conclusions of Lowell of the existence of intelligence in Mars, and that that intelligence has been associated for ages with a planet having only slight elevations of land, a tenuous atmosphere, a scarcity of water which has been utilized for ages through artificial channels, as we have done in various parts of the world since prehistoric times, having vast tracts of sterile plains, and, within these sterile tracts large oases fed by irrigating canals, regions of sparse vegetation, and no large bodies of water; with these conditions going beyond the history of these intelligences, what must be the Martian interpretation of the surface features of this world? It is a perfectly fair inquiry, for by such means we may appreciate the attitude of some of our interpreters of Mars.

In examining the Earth, then, as we have examined Mars, the Martian would find large yellow and reddish areas, extensive greenish areas, and, besides, large regions of varying shades of blue, possibly, occupying three-fourths of the Earth's surface. The yellow areas he would interpret as desert land, the greenish areas he might consider vegetation, but what would he make out of the larger regions of blue? This would certainly puzzle him, because, unfamiliar with oceans, he could not believe that such vast tracts could really be water. He would easily interpret the polar snow caps, and the waters at their edges, but the oceans would be impossible to solve. The suggestion, by some audacious interpreter, that this vast blue area was water, would be answered by showing that these so-called bodies of water bordered vast tracts of sandy deserts with no canals running into them for irrigation or navigation purposes. Even the polar snow caps would be doubted, because they seemed to extend far down into temperate latitudes; and on their recedence in summer, there would be seen no dark, bordering seas as the result of their melting. The vegetation, instead of unfolding at the north and gradually extending southward, would unfold in a contrary direction, appearing first in south temperate latitudes and developing northward. The perennial character of the vegetation in the tropics would puzzle him. Even if he recognized oases in the deserts of America and Africa, the results of Artesian wells or springs, he could not believe them to be vegetation; for he would detect no irrigating canals running into them. He would come to the conclusion that no creature could possibly exist on the Earth, as the tremendous force of gravitation with great atmospheric pressure would forbid the existence of any organic forms. The immense clouds veiling the surface must at times suffer condensation, and the impact of raindrops would, from their velocity and weight, smash everything in the way of life. Life, if it existed in forms supported by appendages, must have legs of iron to sustain its weight, and a crust like a turtle to be impervious to raindrops, and this would be contrary to all Martian analogy. The courses of rivers, if detected, would puzzle him from their irregularity, unless he dared to suggest that these long sinuous channels extending for thousands of miles were identical to the little rivulets he had studied near his own poles.

In fact, about the only feature outside the polar snow caps that he would instantly recognize, would be the great ice cap of the Himalayas. India, that vast region extending from latitude 35° nearly to the equator, with its great plains and sterile regions, with its overpowering heat, and a dense population, depends for the sustenance of many of its millions upon the thousands of miles of irrigating canals, fed from the melting snow caps of the Himalayas. India has no great lakes, but in the northern plains great rivers course their way to the sea. The Ganges and the Indus and their tributaries derive their waters from the melting glaciers, and from these, a most extensive irrigating system of canals and reservoirs draw their waters. As the heat increases the ice melts more rapidly, and so more water is supplied at just the time when it is most needed. The whole scheme is on so vast a scale that a Martian would recognize its meaning, though he would wonder at the tortuous outlines of the larger canals.

Flammarion has, in a similar manner, presented the arguments of Martian astronomers as to whether life exists anywhere but upon the planet Mars. He says, among other fancies, that the sapient Martian argues that houses could not be built on the Earth, on account of the violence with which building materials, such as bricks, blocks, etc., would drop, and thus endanger life. Believing that Mars is rightly balanced as to temperature, the Earth being so much nearer the Sun, would be too hot for life to exist. The Martian conceives himself to be supremely complete "even to the point that artists wishing to represent God in our sanctuaries have figured Him in the image of a Martian man." The Martian considers our year too short. In his reflections he says: "During the period in which one of us attains the middle age of fifty years those on Earth have become decrepit old men of ninety-four, if, indeed, they are not already dead."

Seriously, if there is an intelligence in Mars, it must have evolved along the same general lines as intelligence has developed on the Earth. Being an older planet, it must have outgrown many of the vagaries and illusions which still hamper man in his progress here. In the dim past, however, we can imagine some Martian astronomer with the enigma of our Earth before him, and the great vault of heaven with its thousands of riddles unanswered, consulting records and covering pages with mathematical formulæ to ascertain the precise spot upon which grew the bean stalk by which a Martian Jack ascended to encounter the giant. Indeed, the imagination can conjure up an infinite number of parallels. If Mars is an older sphere, we trust it has long outgrown the superstitions which still hamper man in his interpretation of the inexorable phenomena of Nature on this little planet. We may hope that they have finally reached that stage when a dictum similar to that of Huxley forms an engraved tablet in their temples of worship. These are his words: "Science is teaching the world that the ultimate court of appeal is observation and experiment, and not authority. She is teaching it to estimate the value of evidence; she is creating a firm and living faith in the existence of immutable moral and physical laws, perfect obedience to which is the highest possible aim of an intelligent being."

XVI
SCHIAPARELLI, LOWELL, PERROTIN, THOLLON

Every age has its problem, by solving which humanity is helped forward.

Heinrich Heine.

In previous pages allusion has been made to the distinguished character of the astronomers who have contributed to a knowledge of the surface markings of Mars. Testimony from astronomical sources has been quoted as to their keen-sightedness in this work which, as Sir Robert Ball has said, "indicates one of the utmost refinements of astronomical observation." That the reader may better understand the eminence of some of those whose names will forever be associated with the investigation of the surface features of Mars the following brief records are given.

The two astronomers most widely known in connection with the study of Mars are Professor Giovanni Schiaparelli and Professor Percival Lowell. Lowell had just graduated from Harvard, at the age of twenty-one, when Schiaparelli, at the age of forty-two, made his first great discovery of the canali of Mars. Macpherson, in his valuable history of the "Astronomers of To-day," says of Schiaparelli: "His studies of meteoric astronomy, of Mars, Venus, and Mercury, of double stars and of stellar distribution, have given him a place second to none among living students of the heavens." From the same interesting book we gather the following facts: Schiaparelli was born in Sabigliano, in Piedmont, in 1835. He attended the usual schools in his native town and then entered the University of Turin as a student of mathematics and architecture. Before he was twenty years old he decided to devote himself to the study of astronomy. At the age of twenty-four he was an assistant in the celebrated Observatory of Pulkova. When the kingdom of Italy was organized he became an assistant in the Brera Observatory, Milan. He became suddenly famous at the age of twenty-seven by the discovery of a new asteroid. In 1862 he became Director of the Observatory. Schiaparelli's first great discovery was the relationship between comets and meteoric showers. In 1872 he was accorded the gold medal of the Royal Astronomical Society for his various astronomical discoveries. Professor Simon Newcomb gives him high praise when he says: "Among the individual observers Schiaparelli may be assigned the first place in view of his long continued study of the planets under a fine Italian sky, the conscientious minuteness of his examinations, and his eminence as an investigator." Schiaparelli's researches into the relation of comets and meteors "were developed in 1873, in his remarkable work 'Le Stelle Cardenti,' which is, according to Sir Norman Lockyer, one of the greatest contributions to astronomical literature which the nineteenth century has produced." Macpherson closes his interesting memoir of Schiaparelli by saying: "His devotion to astronomy, his singularly accurate observations and his wonderful discoveries have secured for him an exalted position among the greatest astronomers of modern times." For a further appreciation of the work of Schiaparelli the reader is referred to Macpherson's "Astronomers of To-day." In this brief sketch the reader may judge of the eminent character of one who insists that the lines in Mars are a persistent feature of its surface, whatever one's interpretation of them may be.

Percival Lowell was born in Boston in 1855. He was graduated from Harvard in 1876, and prepared for his graduating thesis an essay on the Nebular Hypothesis. Lowell is a many-sided man. Early interested in mathematics, he became one of the founders of the Mathematical and Physical Society of Boston. A visit to Japan, where he lived a number of years, resulted in the writing of three interesting books: "The Soul of the Far East," 1886; "Noto," 1891; and "Occult Japan," 1894. During his residence in Japan he was chosen foreign Secretary and adviser to the Korean Special Commission, then about to visit the United States, which he accompanied. On his return to Korea he was the guest of the Korean Government, and this experience prompted him to write "A Korean Coup d' État," 1894, and his well-known volume, "Choson, the Land of the Morning Calm," 1885. On his return to America he undertook an eclipse expedition to Tripoli with Professor Todd. His early interest in astronomical subjects was now fully awakened, and the red planet, which he had observed in boyhood with a small telescope from the roof of his father's house, aroused his interest on account of the heated discussions over Schiaparelli's discoveries. With an impetuosity and enthusiasm which characterizes all his work, he set about to secure a proper region and a sufficient elevation for an observatory site. This was found in northern Arizona at an elevation of over 7,000 feet. Here, then, was established the Lowell Observatory with a twenty-four inch refractor made by Clark especially for this Observatory, the last, and, according to the maker's words, the best telescope he had ever made. Lowell insisted that the location of an observatory was a much more important factor than the size of the instrument, and says: "When this is recognized, as it eventually will be, it will become the fashion to put up observatories where they may see rather than be seen." It may be said with truth that, for the first time in the history of astronomy, an observatory has been erected and fitted for the special purpose of studying the surface features of Mars. During unfavorable oppositions Lowell has turned his attention to the other planets, notably Mercury and Venus, with the result of adding many new and interesting details concerning these bodies. Three volumes of quarto memoirs and many bulletins from the Lowell Observatory attest to his industry. He has been fortunate in securing talented assistants, and their contributions may be found in the various publications of the Observatory. The character and importance of Lowell's work may be understood by stating that the "British Nautical Almanac" is to adopt for the future the value of the position of the axis of Mars, and the tilt of the planet's equator to its ecliptic, which was furnished by Professor Lowell in compliance with a request.

Mr. Lowell is a Fellow of the American Academy of Arts and Sciences; Member of the Royal Asiatic Society of Great Britain; American Philosophical Society; Société Astronomique de France; American Astronomical and Astrophysical Society; Astronomische Gesellschaft; Société Belge d'Astronomie; Fellow of the American Geographical Society; Honorary Member Sociedad Astronomica de Mexico; and others.

In 1904 he was awarded the Janssen medal of the Astronomical Society of France for his researches on Mars.

Mr. Macpherson, in his memoir on Lowell, says that "Mr. Lowell, by his unwearied devotion to astronomy, has already gained for himself an enduring reputation."

M. Henry Perrotin and his assistant, M. Thollon, have been quoted in previous pages as having markedly confirmed the discoveries of Schiaparelli. Through the courtesy of Professor Lowell I am enabled to present the likenesses of these two astronomers. I am indebted to the exhaustive work of Miss Agnes M. Clerke, entitled the "History of Astronomy during the Nineteenth Century," for the following memoranda of some of the work accomplished by these men. Perrotin made a series of observations on Venus fully confirming Schiaparelli's inference of synchronous rotation and revolution: "A remarkable collection of drawings made by Mr. Lowell in 1896 appeared decisive in favor of the views of Schiaparelli." In other words, Venus, like the Moon, presents the same face to the Sun in its revolution about that luminary. Perrotin has made important observations on the rings of Saturn; his double-star measurements are also considered work of the highest character.

Thollon has made many spectroscopic studies, among which were delicate experiments showing the lateral displacement of lines in the solar spectrum arising from the Sun's rotation. In the Annals of the Nice Observatory he published a great atlas consisting of thirty-three maps, exhibiting in quadruplicate a subdivision of the solar spectrum under varied conditions of weather and zenith distance. He also studied the spectrum of the great comet of 1882, and by the displacement of its lines estimated that the comet was receding from the Earth at the rate of from sixty-one to seventy-six kilometers per second. The Leland prize was awarded to Thollon for a hand drawing he made of the prismatic spectrum obtained with bisulphide of carbon prisms of high dispersive power.

The character and reputation of these men, as well as others who have been quoted in these pages, must be weighed against the few who, not content with denying the existence of the canali in Mars, have in strong language abused those who accept them as veritable markings on the planet's surface.

XVII
LAST WORDS

The uniformity of the course of Nature will appear as the ultimate major premise of all inductions.

John Stuart Mill.

The final question is, do the lines as depicted and described by various observers exist on the surface of Mars? Those who have made the greatest addition to our knowledge of the character of these lines, and have constructed maps based on Martian latitude and longitude are accredited on other grounds as being endowed with remarkable acuteness of vision coupled with persistence and painstaking care in observation. The most successful work has been accomplished with instruments of fine definition in regions of steady atmosphere and high altitude, or at intervals of clarity and steadiness in regions otherwise unfavorable. Finally, and most convincing of all, Mr. Lowell's assistant, Mr. Lampland, after many attempts has succeeded in photographing the more conspicuous linear markings. The lines do exist essentially as figured by Schiaparelli and Lowell. It now rests with the objectors to suggest any better interpretation of the markings of Mars than that they are the results of intelligent effort.

The mediæval attitude of some astronomers regarding this question recalls the story of Scheiner, a Jesuit brother, who, independently of Galileo and Fabricius, discovered spots on the Sun. Eager with enthusiasm he informed his Superior of his remarkable discovery and begged to be allowed to publish it to the world. The Superior replied, "Go, my son; tranquilize yourself and rest assured that what you take for spots on the Sun are the faults of your glasses or of your eyes." This happened three hundred years ago, and yet to-day a few astronomers of this class still survive.

If one will calmly reason about the matter, let him consider a parallel case of interpretation. He digs out from the ground a fragment of stone; its somewhat symmetrical shape suggests to him the idea that it may be a rude stone implement. If he wishes to know what kind of rock it is and its geological age, he refers it to a geologist; if he wishes to know its composition, he asks a mineralogist, who, if necessary, will analyze it for him. If, however, he is curious to know whether its peculiar, fractured surface is due to frost or other natural agency, or whether it is the work of some rude savage, he inquires of an archæologist, who alone will be able to tell him whether it is a worked stone or natural fragment. He will probably tell him whether it was shaped by paleolithic man, and whether it is a rough stone implement or a core, reject or chip. So with the study of Mars, as we have already pointed out, there are certain matters of information about the planet which the astronomer alone can impart, while the superficial markings are just as certainly to be interpreted by another class of students who may or not be familiar with astronomical methods.