Kitabı oku: «Myths and Marvels of Astronomy», sayfa 15

IX.
THE LUNAR HOAX

Then he gave them an account of the famous moon hoax, which came out in 1835. It was full of the most barefaced absurdities, yet people swallowed it all; and even Arago is said to have treated it seriously as a thing that could not well be true, for Mr. Herschel would have certainly notified him of these marvellous discoveries. The writer of it had not troubled himself to invent probabilities, but had borrowed his scenery from the 'Arabian Nights' and his lunar inhabitants from 'Peter Wilkins.'

—Oliver Wendell Holmes (in The Poet at the Breakfast-Table).

In one of the earliest numbers of 'Macmillan's Magazine, the late Professor De Morgan, in an article on Scientific Hoaxing, gave a brief account of the so-called 'lunar hoax'—an instance of scientific trickery frequently mentioned, though probably few are familiar with the real facts. De Morgan himself possessed a copy of the second English edition of the pamphlet, published in London in 1836. But the original pamphlet edition, published in America in September 1835, is not easily to be obtained. The proprietors of the New York 'Sun,' in which the fictitious narrative first appeared, published an edition of 60,000 copies, and every copy was sold in less than a month. Lately a single copy of that edition was sold for three dollars seventy-five cents.⁴⁵

The pamphlet is interesting in many respects, and I propose to give here a brief account of it. But first it may be well to describe briefly the origin of the hoax.

It is said that after the French revolution of 1830 Nicollet, a French astronomer of some repute, especially for certain lunar observations of a very delicate and difficult kind, left France in debt and also in bad odour with the republican party. According to this story, Arago the astronomer was especially obnoxious to Nicollet, and it was as much with the view of revenging himself on his foe as from a wish to raise a little money that Nicollet wrote the moon-fable. It is said further that Arago was entrapped, as Nicollet desired, and circulated all over Paris the wonders related in the pamphlet, until Nicollet wrote to his friend Bouvard explaining the trick. So runs the story, but the story cannot be altogether true. Nicollet may have prepared the narrative and partly written it, but there are passages in the pamphlet as published in America which no astronomer could have written. Possibly there is some truth in De Morgan's supposition that the original work was French. This may have been Nicollet's: and the American edition was probably enlarged by the translator, who, according to this account, was Richard Alton Locke,⁴⁶ to whom in America the whole credit, or discredit, of the hoax is commonly attributed. There can be no doubt that either the French version was much more carefully designed than the American, or there was no truth in the story that Arago was deceived by the narrative; for in its present form the story, though clever, could not for an instant have deceived any one acquainted with the most elementary laws of optics. The whole story turns on optical rather than on astronomical considerations; but every astronomer of the least skill is acquainted with the principles on which the construction of optical instruments depends. Though the success of the deception recently practised on M. Chasles by the forger of the Pascal papers has been regarded as showing how easily mathematicians may be entrapped, yet even M. Chasles would not have been deceived by bad mathematics; and Arago, a master of the science of optics, could not but have detected optical blunders which would be glaring to the average Cambridge undergraduate.

But let us turn to the story itself.

The account opens with a passage unmistakably from an American hand, though purporting, be it remembered, to be quoted from the 'Supplement to the Edinburgh Journal of Science.' 'In this unusual addition to our journal, we have the happiness of making known to the British public, and thence to the whole civilised world, recent discoveries in astronomy which will build an imperishable monument to the age in which we live, and confer upon the present generation of the human race a proud distinction through all future time. It has been poetically said' [where and by whom?] 'that the stars of heaven are the hereditary regalia of man, as the intellectual sovereign of the animal creation. He may now fold the zodiac around him with a loftier consciousness of his mental supremacy.' To the American mind enwrapment in the star-jewelled zodiac may appear as natural as their ordinary oratorical references to the star-spangled banner; but the idea is essentially transatlantic, and not even the most poetical European astronomer could have risen to such a height of imagery.

Passing over several pages of introductory matter, we come to the description of the method by which a telescope of sufficient magnifying power to show living creatures in the moon was constructed by Sir John Herschel. It had occurred, it would seem, to the elder Herschel to construct an improved series of parabolic and spherical reflectors 'uniting all the meritorious points in the Gregorian and Newtonian instruments, with the highly interesting achromatic discovery of Dolland'(sic). [This is much as though one should say that a clever engineer had conceived the idea of constructing an improved series of railway engines, combining all the meritorious points in stationary and locomotive engines, with Isaac Watts' highly ingenious discovery of screw propulsion. For the Gregorian and Newtonian instruments simply differ in sending the rays received from the great mirror in different directions, and Dolland's discovery relates to the ordinary forms of telescopes with large lens, not with large mirror.] However, accumulating infirmities and eventually death prevented Sir William Herschel from applying his plan, which 'evinced the most profound research in optical science, and the most dexterous ingenuity in mechanical contrivance. But his son, Sir John Herschel, nursed and cradled in the observatory, and a practical astronomer from his boyhood, determined upon testing it at whatever cost. Within two years of his father's death he completed his new apparatus, and adapted it to the old telescope with nearly perfect success.' A short account of the observations made with this instrument, now magnifying six thousand times, follows, in which most of the astronomical statements are very correctly and justly worded, being, in fact, borrowed from a paper by Sir W. Herschel on observation of the moon with precisely that power.

But this great improvement upon all former telescopes still left the observer at a distance of forty miles from the moon; and at that distance no object less than about twenty yards in diameter could be distinguished, and even objects of that size 'would appear only as feeble, shapeless points.' Sir John 'had the satisfaction to know that if he could leap astride a cannon-ball, and travel upon its wings of fury for the respectable period of several millions of years, he would not obtain a more enlarged view of the more distant stars than he could now possess in a few minutes of time; and that it would require an ultra-railroad speed of fifty miles an hour for nearly the livelong year, to secure him a more favourable inspection of the gentle luminary of the night;' but 'the exciting question whether this "observed" of all the sons of men, from the days of Eden to those of Edinburgh, be inhabited by beings, like ourselves, of consciousness and curiosity, was left to the benevolent index of natural analogy, or to the severe tradition that the moon is tenanted only by the hoary solitaire, whom the criminal code of the nursery had banished thither for collecting fuel on the Sabbath-day.'⁴⁷ But the time had arrived when the great discovery was to be made, by which at length the moon could be brought near enough, by telescopic power, for living creatures on her surface to be seen if any exist.

The account of the sudden discovery of the new method, during a conversation between Sir John Herschel and Sir David Brewster, is one of the most cleverly conceived (though also one of the absurdest) passages in the pamphlet. 'About three years ago, in the course of a conversational discussion with Sir David Brewster upon the merits of some ingenious suggestions by the latter, in his article on Optics in the "Edinburgh Encyclopædia," p. 644, for improvements in Newtonian reflectors, Sir John Herschel adverted to the convenient simplicity of the old astronomical telescopes that were without tubes, and the object-glass of which, placed upon a high pole, threw the focal image to a distance of 150 and even 200 feet. Dr. Brewster readily admitted that a tube was not necessary, provided the focal image were conveyed into a dark apartment and there properly received by reflectors.... The conversation then became directed to that all-invincible enemy, the paucity of light in powerful magnifiers. After a few moments' silent thought, Sir John diffidently enquired whether it would not be possible to effect a transfusion of artificial light through the focal object of vision! Sir David, somewhat startled at the originality of the idea, paused awhile, and then hesitatingly referred to the refrangibility of rays, and the angle of incidence. Sir John, grown more confident, adduced the example of the Newtonian reflector, in which the refrangibility was corrected by the second speculum, and the angle of incidence restored by the third.'

All this part of the narrative is simply splendid in absurdity. Hesitating references to refrangibility and the angle of incidence would have been sheerly idiotic under the supposed circumstances; and in the Newtonian reflector (which has only two specula or mirrors) there is no refrangibility to be corrected; apart from which, 'correcting refrangibility' has no more meaning than 'restoring the angle of incidence.'

'"And," continued Sir John, "why cannot the illuminating microscope, say the hydro-oxygen, be applied to render distinct, and, if necessary, even to magnify, the focal object?" Sir David sprung from his chair' [and well he might, though not] 'in an ecstasy of conviction, and, leaping half-way to the ceiling, exclaimed, "Thou art the man!" Each philosopher anticipated the other in presenting the prompt illustration that if the rays of the hydro-oxygen microscope, passed through a drop of water containing the larvæ of a gnat and other objects invisible to the naked eye, rendered them not only keenly but firmly magnified to dimensions of many feet; so could the same artificial light, passed through the faintest focal object of a telescope, both distinctify (to coin a new word for an extraordinary occasion) and magnify its feeblest component members. The only apparent desideratum was a recipient for the focal image which should transfer it, without refranging it, to the surface on which it was to be viewed under the revivifying light of the microscopic reflectors.'

Singularly enough, the idea here mentioned does not appear to many so absurd as it is in reality. It is known that the image formed by the large lens of an ordinary telescope or the large mirror of a reflecting telescope is a real image; not a merely virtual image like that which is seen in a looking-glass. It can be received on a sheet of paper or other white surface just as the image of surrounding objects can be thrown upon the white table of the camera obscura. It is this real image, in fact, which we look at in using a telescope of any sort, the portion of such a telescope nearest to the eye being in reality a microscope for viewing the image formed by the great lens or mirror, as the case may be. And it does not seem to some altogether absurd to speak of illuminating this image by transfused light, or of casting by means of an illuminating microscope a vastly enlarged picture of this image upon a screen. But of course the image being simply formed by the passage of rays (which originally came from the object whose image they form) through a certain small space, to send other rays (coming from some other luminous object) through the same small space, is not to improve, but, so far as any effect is produced at all, to impair, the distinctness of the image. In fact, if these illuminating rays reached the eye, they would seriously impair the distinctness of the image. Their effect may be compared exactly with the effect of rays of light cast upon the image in a camera obscura; and, to see what the effect of such rays would be, we need only consider why it is that the camera is made 'obscura,' or dark. The effect of the transfusion of light through a telescopic image may be easily tried by any one who cares to make the experiment. He has only to do away with the tube of his telescope (substituting two or three straight rods to hold the glass in its place), and then in the blaze of a strong sun to direct the telescope on some object lying nearly towards the sun. Or if he prefer artificial light for the experiment, then at night let him direct the telescope so prepared upon the moon, while a strong electric light is directed upon the place where the focal image is formed (close in front of the eye). The experiment will not suggest very sanguine hopes of good result from the transfusion of artificial light. Yet, to my own knowledge, not a few who were perfectly well aware that the lunar hoax was not based on facts, have gravely reasoned that the principle suggested might be sound, and, in fact, that they could see no reason why astronomers should not try it, even though it had been first suggested as a joke.

To return, however, to the narrative. 'The co-operative philosophers, having hit upon their method, determined to test it practically. They decided that a medium of the purest plate-glass (which it is said they obtained, by consent, be it observed, from the shop-window of M. Desanges, the jeweller to his ex-majesty Charles X., in High Street) was the most eligible they could discover. It answered perfectly with a telescope which magnified a hundred times, and a microscope of about thrice that power.' Thus fortified by experiment, and 'fully sanctioned by the high optical authority of Sir David Brewster, Sir John laid his plan before the Royal Society, and particularly directed to it the attention of his Royal Highness the Duke of Sussex, the ever munificent patron of science and the arts. It was immediately and enthusiastically approved by the committee chosen to investigate it, and the chairman, who was the Royal President' (this continual reference to royalty is manifestly intended to give a British tone to the narrative), 'subscribed his name for a contribution of £10,000, with a promise that he would zealously submit the proposed instrument as a fit object for the patronage of the privy purse. He did so without delay; and his Majesty, on being informed that the estimated expense was £70,000, naïvely enquired if the costly instrument would conduce to any improvement in navigation. On being informed that it undoubtly would, the sailor king promised a carte blanche for any amount which might be required.'

All this is very clever. The 'sailor king' comes in as effectively to give vraisemblance to the narrative as 'Crabtree's little bronze Shakspeare that stood over the fireplace,' and the 'postman just come to the door with a double letter from Northamptonshire.'

Then comes a description of the construction of the object-glass, twenty-four feet in diameter, 'just six times the size of the elder Herschel's;' who, by the way, never made a telescope with an object-glass. The account of Sir John Herschel's journey from England, and even some details of the construction of the observatory, were based on facts, indeed, so many persons in America as well as in England were acquainted with some of these circumstances, that it was essential to follow the facts as closely as possible. Of course, also, some explanation had to be given of the circumstance that nothing had before been heard respecting the gigantic instrument taken out by Sir John Herschel. 'Whether,' says the story, 'the British Government were sceptical concerning the promised splendour of the discoveries, or wished them to be scrupulously veiled until they had accumulated a full-orbed glory for the nation and reign in which they originated, is a question which we can only conjecturally solve. But certain it is that the astronomer's royal patrons enjoined a masonic taciturnity upon him and his friends until he should have officially communicated the results of his great experiment.'

It was not till the night of January 10, 1835, that the mighty telescope was at length directed towards our satellite. The part of the moon selected was on the eastern part of her disc. 'The whole immense power of the telescope was applied, and to its focal image about one half of the power of the microscope. On removing the screen of the latter, the field of view was covered throughout its entire area with a beautifully distinct and even vivid representation of basaltic rock. Its colour was a greenish brown; and the width of the columns, as defined by their interstices on the canvas, was invariably twenty-eight inches. No fracture whatever appeared in the mass first presented; but in a few seconds a shelving pile appeared, of five or six columns' width, which showed their figure to be hexagonal, and their articulations similar to those of the basaltic formation at Staffa. This precipitous cliff was profusely covered with a dark red flower, precisely similar, says Dr. Grant, to the Papaver Rhœus, or Rose Poppy, of our sublunary cornfields; and this was the first organic production of nature in a foreign world ever revealed to the eyes of men.'

It would be wearisome to go through the whole series of observations thus fabled, and only a few of the more striking features need be indicated. The discoveries are carefully graduated in interest. Thus we have seen how, after recognising basaltic formations, the observers discovered flowers: they next see a lunar forest, whose 'trees were of one unvaried kind, and unlike any on earth except the largest kind of yews in the English churchyards.' (There is an American ring in this sentence, by the way, as there is in one, a few lines farther on, where the narrator having stated that by mistake the observers had the Sea of Clouds instead of a more easterly spot in the field of view, proceeds to say: 'However, the moon was a free country, and we not as yet attached to any particular province.') Next a lunar ocean is described, 'the water nearly as blue as that of the deep sea, and breaking in large white billows upon the strand, while the action of very high tides was quite manifest upon the face of the cliffs for more than a hundred miles.' After a description of several valleys, hills, mountains and forests, we come to the discovery of animal life. An oval valley surrounded by hills, red as the purest vermilion, is selected as the scene. 'Small collections of trees, of every imaginable kind, were scattered about the whole of this luxuriant area; and here our magnifiers blessed our panting hopes with specimens of conscious existence. In the shade of the woods we beheld brown quadrupeds having all the external characteristics of the bison, but more diminutive than any species of the bos genus in our natural history.' Then herds of agile creatures like antelopes are described, 'abounding on the acclivitous glades of the woods.' In the contemplation of these sprightly animals the narrator becomes quite lively. 'This beautiful creature,' says he, 'afforded us the most exquisite amusement. The mimicry of its movements upon our white painted canvas was as faithful and luminous as that of animals within a few yards of the camera obscura. Frequently, when attempting to put our fingers upon its beard, it would suddenly bound away as if conscious of our earthly impertinence; but then others would appear, whom we could not prevent nibbling the herbage, say or do to them what we would.'

A strange amphibious creature, of a spherical form, rolling with great velocity along a pebbly beach, is the next object of interest, but is presently lost sight of in a strong current setting off from the angle of an island. After this there are three or four pages descriptive of various lunar scenes and animals, the latter showing a tendency, singular considering the circumstances, though very convenient for the narrator, to become higher and higher in type as the discoveries proceed, until an animal somewhat of the nature of the missing link is discovered. It is found in the Endymion (a circular walled plain) in company with a small kind of reindeer, the elk, the moose, and the horned bear, and is described as the biped beaver. It 'resembles the beaver of the earth in every other respect than in its destitution of a tail, and its invariable habit of walking upon only two feet. It carries its young in its arms like a human being, and moves with an easy gliding motion. Its huts are constructed better and higher than those of many tribes of human savages, and, from the appearance of smoke in nearly all of them, there is no doubt of its being acquainted with the use of fire. Still, its head and body differ only in the points stated from that of the beaver; and it was never seen except on the borders of lakes and rivers, in which it has been observed to immerse for a period of several seconds.'

The next step towards the climax brings us to domestic animals, 'good large sheep, which would not have disgraced the farms of Leicestershire or the shambles of Leadenhall Market; we fairly laughed at the recognition of so familiar an acquaintance in so distant a land. Presently they appeared in great numbers, and, on reducing the lenses, we found them in flocks over a great part of the valley. I need not say how desirous we were of finding shepherds to these flocks, and even a man with blue apron and rolled-up sleeves would have been a welcome sight to us, if not to the sheep; but they fed in peace, lords of their own pastures, without either protector or destroyer in human shape.'

In the meantime, discussion had arisen as to the lunar locality where men, or creatures resembling them, would most likely be found. Herschel had a theory on the subject—viz., that just where the balancing or libratory swing of the moon brings into view the greatest extent beyond the eastern or western parts of that hemisphere which is turned earthwards in the moon's mean or average position, lunar inhabitants would probably be found, and nowhere else. This, by the way (speaking seriously), is a rather curious anticipation of a view long subsequently advanced by Hansen, and for a time adopted by Sir J. Herschel, that possibly the remote hemisphere of the moon may be a fit abode for living creatures, the oceans and atmosphere which are wanting on the nearer hemisphere having been (on this hypothesis) drawn over to the remoter because of a displacement of the moon's centre of gravity. I ventured in one of my first books on astronomy to indicate objections to this theory, the force of which Sir J. Herschel admitted in a letter addressed to me on the subject.

Taking, then, an opportunity when the moon had just swung to the extreme limit of her balancing, or, to use technical terms, when she had attained her maximum libration in longitude, the observers approached the level opening to Lake Langrenus, as the narrator calls this fine walled plain, which, by the way, is fully thirty degrees of lunar longitude within the average western limit of the moon's visible hemisphere. 'Here the valley narrows to a mile in width, and displays scenery on both sides picturesque and romantic beyond the powers of a prose description. Imagination, borne on the wings of poetry, could alone gather similes to portray the wild sublimity of this landscape, where dark behemoth crags stood over the brows of lofty precipices, as if a rampart in the sky; and forests seemed suspended in mid-air. On the eastern side there was one soaring crag, crested with trees, which hung over in a curve like three-fourths of a Gothic arch, and being of a rich crimson colour, its effect was most strange upon minds unaccustomed to the association of such grandeur with such beauty. But, whilst gazing upon them in a perspective of about half a mile, we were thrilled with astonishment to perceive four successive flocks of large winged creatures, wholly unlike any kind of birds, descend with a slow even motion from the cliffs on the western side and alight upon the plain. They were first noticed by Dr. Herschel, who exclaimed: "Now, gentlemen, my theories against your proofs, which you have often found a pretty even bet, we have here something worth looking at. I was confident that if ever we found beings in human shape it would be in this longitude, and that they would be provided by their Creator with some extraordinary powers of locomotion." … We counted three parties of these creatures, of twelve, nine, and fifteen in each, walking erect towards a small wood near the base of the eastern precipices. Certainly they were like human beings, for their wings had now disappeared, and their attitude in walking was both erect and dignified.... They averaged four feet in height, were covered, except on the face, with short and glossy copper-coloured hair, lying snugly upon their backs, from the top of the shoulders to the calves of the legs. The face, which was of a yellowish flesh colour, was a slight improvement upon that of the large orang outang, being more open and intelligent in its expression, and having a much greater expansion of forehead. The mouth, however, was very prominent, though somewhat relieved by a thick beard upon the lower jaw, and by lips far more human than those of any species of the simia genus. In general symmetry of body and limbs they were infinitely superior to the orang outang; so much so, that, but for their long wings, Lieutenant Drummond said they would look as well on a parade ground as some of the old Cockney militia.... These creatures were evidently engaged in conversation; their gesticulation, more particularly the varied action of their hands and arms, appeared impassioned and emphatic. We hence inferred that they were rational beings, and, although not perhaps of so high an order as others which we discovered the next month on the shores of the Bay of Rainbows, that they were capable of producing works of art and contrivance.... They possessed wings of great expansion, similar in construction to those of the bat, being a semi-transparent membrane united in curvilinear divisions by means of straight radii, united at the back by the dorsal integuments. But what astonished us very much was the circumstance of this membrane being continued from the shoulders to the legs, united all the way down, though gradually decreasing in width' (very much as Fuseli depicted the wings of his Satanic Majesty, though H.S.M. would seem to have the advantage of the lunar Bat-men in not being influenced by gravity⁴⁸). 'The wings seemed completely under the command of volition, for those of the creatures whom we saw bathing in the water spread them instantly to their full width, waved them as ducks do theirs to shake off the water, and then as instantly closed them again in a compact form. Our further observation of the habits of these creatures, who were of both sexes, led to results so very remarkable, that I prefer they should be first laid before the public in Dr. Herschel's own work, where I have reason to know they are fully and faithfully stated, however incredulously they may be received.... We scientifically denominated them the Vespertilio-homo or Bat-man; and they are doubtless innocent and happy creatures, notwithstanding that some of their amusements would but ill comport with our terrestrial notions of decorum.' The omitted passages were suppressed in obedience to Dr. Grant's private injunction. 'These, however, and other prohibited passages,' were to be presently 'published by Dr. Herschel, with the certificates of the civil and military authorities of the colony, and of several Episcopal, Wesleyan, and other ministers, who in the month of March last were permitted, under stipulation of temporary secrecy, to visit the observatory, and become eye-witnesses of the wonders which they were requested to attest. We are confident that his forthcoming volumes will be at once the most sublime in science, and the most intense in general interest, that ever issued from the press.'

The actual climax of the narrative, however, is not yet reached. The inhabitants of Langrenus, though rational, do not belong to the highest orders of intelligent Lunarians. Herschel, ever ready with theories, had pointed out that probably the most cultivated races would be found residing on the slopes of some active volcano, and, in particular, that the proximity of the flaming mountain Bullialdus (about twenty degrees south and ten east of the vast crater Tycho, the centre whence extend those great radiations which give to the moon something of the appearance of a peeled orange) 'must be so great a local convenience to dwellers in this valley during the long periodical absence of solar light, as to render it a place of popular resort for the inhabitants of all the adjacent regions, more especially as its bulwark of hills afforded an infallible security against any volcanic eruption that could occur.' Our observers therefore applied their full power to explore it. 'Rich, indeed, was our reward. The very first object in this valley that appeared upon our canvas was a magnificent work of art. It was a temple—a fane of devotion or of science, which, when consecrated to the Creator, is devotion of the loftiest order, for it exhibits His attributes purely, free from the masquerade attire and blasphemous caricature of controversial creeds, and has the seal and signature of His own hand to sanction its aspirations. It was an equi-angular temple, built of polished sapphire, or of some resplendent blue stone, which, like it, displayed a myriad point of golden light twinkling and scintillating in the sunbeams.... The roof was composed of yellow metal, and divided into three compartments, which were not triangular planes inclining to the centre, but subdivided, curved, and separated so as to present a mass of violently agitated flames rising from a common source of conflagration, and terminating in wildly waving points. This design was too manifest and too skilfully executed to be mistaken for a single moment. Through a few openings in these metallic flames we perceived a large sphere of a darker kind of metal nearly of a clouded copper colour, which they enclosed and seemingly raged around, as if hieroglyphically consuming it.... What did the ingenious builders mean by the globe surrounded by flames? Did they, by this, record any past calamity of their world, or predict any future one of ours?' (Why, by the way, should the past theory be assigned to the moon and the future one to our earth?) 'I by no means despair of ultimately solving not only these but a thousand other questions which present themselves respecting the objects in this planet; for not the millionth part of her surface has yet been explored, and we have been more desirous of collecting the greatest possible number of new facts than of indulging in speculative theories, however seductive to the imagination.'