Golden Age of Science Fiction Vol IX

by Various

  "It had long been reasoned that, as the earth was accompanied by a moon, and Jupiter had at least four, Mars, the intermediate planet, might be expected to possess a satellite. The planet itself being small, its moon would probably be very small, and likely to be overlooked when observing with the telescope, because its light would be overpowered by the light of the planet, which would make the telescopic field of view very bright. Up to the year 1877 the most powerful instruments had been used without success in the search for the supposed satellite.

  "In that year Mars made an exceptionally near approach to the earth, and Professor Asaph Hall, of Washington Observatory, took up the search, using a splendid refracting telescope having an object-glass 26 inches in diameter. The methods he adopted were rewarded with success, for he discovered not only one, but two satellites of Mars, and they were given the names of Phobos and Deimos.

  "Both these satellites are very close to the planet and extremely small, Phobos being less than 4000 miles from the planet's surface, and Deimos only 12,300 miles from it. As seen in the telescope, they are very faint points of light which cannot be measured by ordinary means, and the estimation of their size was a matter of great difficulty.

  "Professor Langley gives an interesting account of the endeavour to estimate their size by the amount of light reflected, as compared with the light afforded by our own moon when full. It was a most difficult task, as the comparison had to be made by means of tiny holes drilled in metal plates; and for a long time it was impossible to find a workman who could drill a hole sufficiently small for the purpose, although one of those employed had succeeded in drilling a hole through a lady's thin cambric needle from end to end, thus converting it into a tiny steel tube. One would have thought such a feat impossible; yet what was now required was a hole smaller than the one thus made through the tiny needle."

  "My word!" said M'Allister, "I would like to see the mon who did that piece of work, and shake hands with him; he must be a rare clever fellow!"

  "Yes," said John, "and I would like to see the drill he used; for such a long and extremely slender tool, to be effective, must be as clever a piece of work as the steel tube."

  "I may tell you," I proceeded, "that success was at last attained; and as a result of the comparison of our moon's light with that of Deimos, it was shown that if the general surface brightness of the latter were equal to that of our moon, then Deimos must be only 18 miles in diameter, or about a 15,000th part of the area of our moon's disc.

  "To state the matter in another way--supposing our moon were only 18 miles in diameter, and was removed to the same distance as Deimos is from us, then it would appear only the very faint point of light that Deimos appears when viewed through the telescope.

  "By the same means Phobos, the satellite nearest to Mars, was estimated to be about 22-1/2 miles in diameter. These dimensions, however, depend on the brightness of these satellites being exactly the same as the general brightness of our moon; and later experiments have fixed the sizes as 36 miles for Phobos, and 10 miles as the diameter of Deimos.

  "I will not detain you much longer on this subject, as we shall be able to discuss it further when we arrive upon Mars; but I may now mention that, in one respect, the little satellite named Phobos is unique. It is the only satellite we know of which revolves round its primary planet in less time than it takes the planet itself to make one revolution on its axis.[6]

  "Mars revolves on its axis in 24 hours, 37 minutes, and 22 seconds, thus the 'day' on Mars is nearly 38 minutes longer than our 'day.' Phobos revolves round the planet in the very short period of 7 hours, 39 minutes, and 14 seconds, and therefore makes more than three complete revolutions round the planet in the course of a single Martian day. The peculiar phenomena to which this very rapid motion gives rise, and the numerous eclipses which occur, will be matters of great interest to us all when we reach Mars. Our moon, as you know, takes a month to make one revolution round the earth."

  "Professor," said John, "when we get to Mars, it will be rather a curious experience for us to see two moons shining in the sky at the same time!"

  "My word!" exclaimed M'Allister, "two moons shining at once! If I go out and see such a sight as that, I shall think the whisky has been a wee bit too strong for me!"

  "Well," replied John, "if your usual drink has the effect of making you see double, take good advice, and leave the whisky severely alone when you are on Mars, or else you will be seeing four moons all at once, and receive such a shock that you will never get over it!"

  M'Allister laughed pleasantly as John said this. He is a real good fellow, and takes all John's chaff with the utmost good-humour; but, in justice to him, I must say that, although he sticks to his national drink like a true Scot, I have never once seen him any the worse for it. He knows his limitations, and always keeps within them.

  CHAPTER X

  THE DISCOVERY OF LINES UPON MARS--THE GREAT MARTIAN CONTROVERSY

  After the little interlude with M'Allister, I resumed my remarks by saying that "The year 1877, so memorable for the near approach of Mars and the discovery of its two tiny satellites, was also the year in which a still more important discovery was made--a discovery, in fact, which has much enlarged our knowledge of the planet, and has also resulted in an entire revision of our conceptions respecting it.

  "An Italian astronomer, Signor Schiaparelli, took advantage of the favourable position of Mars to observe it very carefully, and some time afterwards announced that he had seen upon its surface a number of very fine lines which had not previously been noticed, and these he had carefully charted upon his drawings and maps.

  "This announcement started one of the most acrimonious discussions that the astronomical world has ever known; and although it is now over thirty years since it commenced, astronomers are still divided into two parties--one accepting the lines as demonstrated facts, the other either denying their existence, or endeavouring to explain them away by various more or less ingenious or fanciful theories.

  [Illustration: From a Globe made by M. Wicks Plate VIII

  MARS. MAP I

  In all these maps the south is at the top. The dark shaded portions are vegetation, mostly on old sea-beds. The fine lines are the canals, and the round dots the oases. The light areas are deserts. Longitude "0" is seen on the Equator between the two forks of the "Sabaeus Sinus."]

  "When Signor Schiaparelli's statements and drawings were first discussed, it was declared by some to be quite impossible that these fine lines could really have been seen by him: either his eyes must have been overstrained, or he claimed to see more than he actually did see. So warm did the discussion become that he soon withdrew from it altogether, but devoted himself to his work. As time went on, he not only verified his previous discoveries, but found numerous fresh lines, all of which appeared to run straight and true over many hundreds of miles on the planet.

  "Milan then had a good clear atmosphere which was favourable for the observation of delicate planetary markings, and other observers who were well situated were able to see and draw many of the lines which Schiaparelli had discovered.

  "It was, however, contended that such lines could not have any real existence, as it was asserted that they were too straight. It is quite true that straight lines on a rotating globe would appear curved when seen from some points of view, but if the objectors had carefully studied complete sets of drawings, they would have seen that the lines did assume a curved form in certain aspects of the planet.

  "Then the very same people who denied the actuality of the lines because they were too straight, eagerly took up a suggestion that they were not actually narrow lines, but the edges of diffused shadings on the planet, apparently quite oblivious of the fact that the same objections must apply to them. Moreover, if there was difficulty in accepting the actuality of narrow lines, there must be immensely greater difficulty in believing that shadings could, in such a very large number of cases, all end in straight lines many hundreds or thousands of mil
es long, and always appear uniformly true, no matter upon what portion of the disc they might be seen, and whatever might be the angle of illumination.

  "Besides, only a small proportion of the lines are connected with shadings. The shadings are more likely to be the result of the canals than the cause of the formation of illusory lines in so many cases.

  "I have listened to many of these discussions, and have often been much amused at the tangle of inconsistencies in which some have involved themselves, by taking up fresh theories without regard to their previous contentions.

  "As time went on each opposition of Mars brought the discovery of fresh lines, and numerous observers confirmed the reality of Schiaparelli's work.

  "Professor Lowell, the well-known American astronomer, took up the study of Mars in a most thorough and systematic manner, and has since practically made it his life's work. An observatory was built at Flagstaff, Arizona, far away from towns and smoke, at an altitude of over 6000 feet above the sea-level, the site being specially selected on account of the clearness and purity of its atmosphere; while the observatory, being high up above the denser and more disturbed strata of air, afforded the most favourable situation possible for the proper observation of delicate planetary detail.

  "There he continued the work which Schiaparelli had commenced, and, together with the colleagues with whom he has been associated, has, by long-continued and most systematic work, added greatly to our knowledge of Mars. Year after year has seen the addition of more lines on our maps of the planet, whilst many interesting discoveries have been made--one being that some of the fine lines were double, the second line always being equidistant from the first one throughout its whole length, no matter whether the lines were straight or curved.

  "This caused a further outcry of objection. The observers were told that they had been overstraining their eyesight so that they 'saw double,' and also that they had been using telescopes not properly focussed. Such objections seem almost beyond argument, for no practical observer could use an improperly focussed instrument without at once discovering the defect.

  "Besides, if the double lines were the result of eye-strain, or any other defect which might cause such illusions, all the lines would have been seen double, or at least all the lines running at the same angles; but as a matter of fact only a very small proportion of the lines were so seen, and it made no difference what position they occupied on the disc, or at what angles they were presented. Some of the doubles were, in fact, curved lines; and another point was that in some cases they were only doubled at certain seasons of the year.

  "Other observers who saw the lines were charged with having studied the maps of Schiaparelli and Lowell until they had become obsessed with the lines, and when they looked through the telescope simply fancied they saw them!

  "In England our atmospheric conditions are seldom really favourable to the proper seeing of the finer detail, and the very faint lines cannot be seen at all. The lines that are visible do not appear thin and sharp as they do to observers in more favoured climes, but rather as diffused smudgy lines, and so they are drawn by the observers. On a few occasions of exceptionally good seeing they have, however, been seen and drawn as finer and sharper lines.

  "The visibility of the lines was, however, confirmed by so many observers of known integrity, and from so many different parts of the world, that the objectors were at last compelled to abandon the position they had occupied. Then a new theory was started, viz. that the lines were actually seen but did not actually exist, being really optical illusions arising from the apparent integration, or running together in linear form, of various small disconnected markings which were viewed from beyond the distance of clear seeing.

  "The manner in which it was sought to prove the correctness of this theory appeared to me at the time (and still does so) as most weak and fallacious, and certain experiments I made only strengthened that opinion. However, scientific people accepted it as proof.

  "In making this experiment schoolboys were seated in rows at different measured distances from a map of Mars, which they were told to copy. The map showed all the well-known dark patches and markings, but no fine lines. About the places where some of those lines should have been, dots, curls, wisps, &c., were inserted at irregular distances, and not always exactly where the lines should have been shown. The inevitable result was that the boys who were too far away to see clearly saw these small markings as continuous straight lines, and so drew them. In the circumstances they could not do otherwise; for if sufficient marks were inserted nearly in alignment, they would necessarily produce the effect of lines.

  "These drawings were then acclaimed as proving that the lines seen on Mars were only discrete markings viewed from beyond the distance of clear seeing, and that the network of lines seen and drawn by so many skilled and careful observers of Mars had no actual existence upon the planet. Thus all their work was completely discredited.

  "Experiments like these could not possibly prove any such thing, because it would be easy to insert in a map various markings which, when viewed from a distance, would appear to form almost any design that one might choose to depict. Any desired effect might thus be obtained; and I have seen many pictures so formed in which the illusion was perfect. When viewed from a distance each appeared to be a picture of something entirely different from what was seen when it was viewed from a near standpoint.

  "The linear illusion could not arise from a mere multiplicity of faint scattered markings, but all the more conspicuous markings must be in alignment. It seems impossible to imagine that so many hundreds of lines on Mars could thus fortuitously be formed by illusion, and every line be connected to some definite point at each end.

  "To argue that because illusory lines can be formed as in these experiments proves that the Martian lines are also illusions is claiming far too much. For instance, if I drew what was actually a map of South Africa, and was so seen at close quarters, yet in consequence of the insertion of numerous small marks and shadings formed a portrait of Lord Blank when viewed from a distance, it would be very far indeed from proving that every map of South Africa was a portrait of the noble lord, or that his portraits were all maps of South Africa.

  "Moreover, as I myself saw, some of the boys were so unskilled that they had not even drawn correctly the outlines of the dark patches about which there was no dispute.

  "It is obvious that such erroneous and unreliable work as this could not be regarded as evidence upon which truly scientific argument could be founded for the purpose of deciding such a contentious question; yet mainly upon this very slender and unreliable evidence meetings of two of our leading astronomical associations endorsed the illusion theory, and for a long time it held the field.

  "M. Flammarion made some similar experiments in Paris, and even inserted spaced dots along the sites of canal lines on the map put up as a copy, yet not one boy drew a canal. M. Flammarion evidently was rather too sparing with his dots and marks.

  "A long series of experiments was carefully carried out by Professor Lowell and his colleagues, from which it was deduced that if in any line on Mars there was a gap of sixteen miles in length, our present telescopes would suffice to discover it. It is most improbable that in so many hundreds of lines, several of which are over two thousand miles in length, there would not be numerous gaps over sixteen miles long if the lines were made up of separate markings.

  "Yet it is found that every line is perfect in its continuity, and not only so, but uniform in width throughout its whole length, which would be impossible if the lines were made up of separate markings not in alignment.

  "The illusion theory may, however, to a certain extent be correct, but this will prove exactly the opposite of what its supporters contend. It appears to have been quite overlooked that as there are so many thousands of miles of canals it is utterly impossible to suppose that the vegetation, which is all that we really see, is continuous and without breaks. It would indeed be most extraordinary if there w
ere not very many long stretches of land which, for some natural or utilitarian reasons, were either bare of vegetation or so sparsely covered as to appear bare when viewed from the earth through a telescope. Some parts of the canals in hilly or rocky ground may pass through tunnels, and thus cause apparent gaps in the lines; or ground may be incapable of bearing vegetation, or purposely left fallow.

  "It would, therefore, be no matter of surprise if more powerful instruments should, in moments of perfect seeing, reveal numerous apparent gaps in the lines. So far from proving they were not canals, such gaps are exactly what we should expect to find in connection with canals; and the lines would probably appear as irregular light and dark patches in alignment, because we do not see the canals themselves, but only the vegetation on the land which they traverse. Probably there are also many oases yet to be discovered along the canal lines.

  "As I have already stated, it was asserted that the double lines were illusions arising from the causes already mentioned, with the probable addition of eye-strain and bad focussing. Assuming that the single lines are, as it is declared, illusions, we are confronted with the assumption that the doubles are illusions of illusions, and this is more than I can follow, it seems so improbable.

  "Professor Lowell has devoted some sixteen years to close and continuous observation of Mars whenever it has been in a position to be observed, and many thousands of drawings have been made, the results being plotted down on a globe. In reply to the statements of occasional observers that the lines cannot be seen, he testifies that they are not difficult to see; and that any one who saw them in his exceptionally good atmosphere, and through his instruments, could have no doubt of their actuality. He rather caustically, but very justly, remarks in one of his books that his many years of personal experience in viewing these lines almost entitle him to an opinion on the subject equal to those who have had none at all!