Myths and Marvels of Astronomy Part 13

Herschel, anxiously though he endeavoured to guard against the possibility of error, was certainly mistaken. Ura.n.u.s may, for anything that is known to the contrary, have many small satellites circulating about him, but he certainly has not four satellites (besides those known) which could have been seen by Sir W. Herschel with the telescope he employed. For the neighbourhood of the planet has been carefully examined with telescopes of much greater power by observers who with those telescopes have seen objects far fainter than the satellites supposed to have been seen by the elder Herschel.

The third of the Herschelian myths was the lunar volcano in eruption, which he supposed he had seen in progress in that part of the moon which was not at the time illuminated by the sun's rays. He saw a bright star-like point of light, which corresponded in position with the crater of the lunar mountain Aristarchus. He inferred that a volcano was in active eruption because the brightness of the point of light varied from time to time, and also because he did not remember to have seen it before under the same conditions. There is no doubt something very remarkable in the way in which this part of the moon's surface s.h.i.+nes when not illumined by the sun. If it were always bright we should conclude at once that the earth-light s.h.i.+ning upon it rendered it visible. For it must be remembered that the part of the moon which looks dark (or seems wanting to the full disc) is illuminated by our earth, s.h.i.+ning in the sky of the moon as a disc thirteen times as large as that of the moon we see, and with the same proportion of its disc sunlit as is dark in the moon's disc. Thus when the moon is nearly new our earth is s.h.i.+ning in the lunar skies as a nearly full moon thirteen times as large as ours. The light of this n.o.ble moon must illumine the moon's surface much more brightly than a terrestrial landscape is illumined by the full moon, and if any parts of her surface are very white they will s.h.i.+ne out from the surface around, just as the snow-covered peak of a mountain s.h.i.+nes out upon a moonlit night from among the darker hills and dales and rocks and forests of the landscape. But Herschel considered that the occasional brightness of the crater Aristarchus could not be thus explained. The spot had been seen before the time of Herschel's observations by Ca.s.sini and others. It has been seen since by Captain Kater, Francis Baily, and many others. Dr. Maskelyne tells us that in March 1794 it was seen by the naked eye by two persons.

Baily thus describes the appearance presented by this lunar crater on December 22, 1835: 'Directed telescope to the moon, and pointing it to the dark part in the vicinity of Aristarchus, soon saw the outline of that mountain very distinctly, formed like an irregular nebula. Nearly in the centre was a light resembling that of a star of the ninth or tenth magnitude. It appeared by glimpses, but at times was brilliant, and visible for several seconds together.'

There can be little doubt, however, that the apparent brightness of this lunar crater, or rather of its summit, is due to some peculiar quality in the surface, which may perhaps be covered by some crystalline or vitreous matter poured out in the far distant time when the crater was an active one. Prof. Shaler, who examined the crater when it was illuminated only by earths.h.i.+ne, with the fine 15-inch telescope of the Harvard Observatory (Cambridge U.S.), says that he has been able to recognise nearly all the craters over 15 miles in diameter in the dark part. 'There are several degrees of brightness,' he says, 'observable in the different objects which s.h.i.+ne out by the earth-light. This fact probably explains the greater part of the perplexing statements concerning the illumination of certain craters. It certainly accounts for the volcanic activity which has so often been supposed to be manifested by Aristarchus. Under the illumination by the earth-light this is by far the brightest object on the dark part of the moon's face, and is visible much longer and with poorer gla.s.ses than any other object there.'

Here my record of astronomical myths must be brought to a close. It will be noticed that in every instance either the illusion has affected the actual observations of eminent and skilful astronomers, or has caused such astronomers to put faith for a while in illusory observations. Had I cared to include the mistakes which have been made by or have misled observers of less experience, I could have filled many sheets for each page of the present article. But it has seemed to me more instructive to show how error may affect the observations even of the most careful and deservedly eminent astronomers, how even the most cautious may be for a time misled by the mistakes of inferior observers, especially when the fact supposed to have been observed accords with preconceived opinions.

XII.

_THE ORIGIN OF THE CONSTELLATION-FIGURES._

Although the strange figures which astronomers still allow to straggle over their star maps no longer have any real scientific interest, they still possess a certain charm, not only for the student of astronomy, but for many who care little or nothing about astronomy as a science.

When I was giving a course of twelve lectures in Boston, America, a person of considerable culture said to me, 'I wish you would lecture about the constellations; I care little about the sun and moon and the planets, and not much more about comets; but I have always felt great interest in the Bears and Lions, the Chained and Chaired Ladies, King Cepheus and the Rescuer Perseus, Orion, Ophiuchus, Hercules, and the rest of the mythical and fanciful beings with which the old astronomers peopled the heavens. I say with Carlyle, "Why does not some one teach me the constellations, and make me at home in the starry heavens, which are always overhead, and which I don't half know to this day."' We may notice, too, that the poets by almost unanimous consent have recognised the poetical aspect of the constellations, while they have found little to say about subjects which belong especially to astronomy as a science.

Milton has indeed made an Archangel reason (not unskilfully for Milton's day) about the Ptolemaic and Copernican systems, while Tennyson makes frequent reference to astronomical theories. 'There sinks the nebulous star we call the Sun, if that hypothesis of theirs be sound,' said Ida; but she said no more, save 'let us down and rest,' as though the subject were wearisome to her. Again, in the Palace of Art the soul of the poet having built herself that 'great house so royal, rich, and wide,'

thither--

... when all the deep unsounded skies Shuddered with silent stars, she clomb, And as with optic gla.s.ses her keen eyes Pierced through the mystic dome, Regions of lucid matter taking forms, Brushes of fire, hazy gleams, Cl.u.s.ters and beds of worlds and beelike swarms Of suns, and starry streams: She saw the snowy poles of moonless Mars, That marvellous round of milky light Below Orion, and those double stars Whereof the one more bright Is circled by the other.

But the poet's soul so wearied of these astronomical researches that the beautiful lines I have quoted disappeared (more's the pity) from the second and all later editions. Such exceptions, indeed, prove the rule.

Poets have been chary in referring to astronomical researches and results, full though these have been of unspeakable poetry; while from the days of Homer to those of Tennyson, the constellations which 'garland the heavens' have always been favourite subjects of poetic imagery.

It is not my present purpose, however, to discuss the poetic aspect of the constellations. I propose to inquire how these singular figures first found their way to the heavens, and, so far as facts are available for the purpose, to determine the history and antiquity of some of the more celebrated constellations.

Long before astronomy had any existence as a science men watched the stars with wonder and reverence. Those orbs, seemingly countless--which bespangle the dark robe of night--have a charm and beauty of their own apart from the significance with which the science of astronomy has invested them. The least fanciful mind is led to recognise on the celestial concave the emblems of terrestrial objects, pictured with more or less distinctness among the mysterious star-groupings. We can imagine that long before the importance of the study of the stars was recognised, men had begun to a.s.sociate with certain star-groups the names of familiar objects animate or inanimate. The flocks and herds which the earliest observers of the heavens tended would suggest names for certain sets of stars, and thus the Bull, the Ram, the Kids, would appear in the heavens. Other groups would remind those early observers of the animals from whom they had to guard their flocks, or of the animals to whose vigilance they trusted for protection, and thus the Bear, the Lion, and the Dogs would find their place among the stars. The figures of men and horses, and of birds and fishes, would naturally enough be recognised, nor would either the implements of husbandry, or the weapons by which the huntsman secured his prey, remain unrepresented among the star-groupings. And lastly, the altar on which the first-fruits of harvest and vintage were presented, or the flesh of lambs and goats consumed, would be figured among the innumerable combinations which a fanciful eye can recognise among the orbs of heaven.

In thus suggesting that the first observers of the heavens were shepherds, huntsmen, and husbandmen, I am not advancing a theory on the difficult questions connected with the origin of exact astronomy. The first observations of the heavens were of necessity made by men who depended for their subsistence on a familiarity with the progress and vicissitudes of the seasons, and doubtless preceded by many ages the study of astronomy as a science. And yet the observations made by those early shepherds and hunters, unscientific though they must have been in themselves, are full of interest to the student of modern exact astronomy. The a.s.sertion may seem strange at first sight, but is nevertheless strictly true, that if we could but learn with certainty the names a.s.signed to certain star-groups, before astronomy had any real existence, we could deduce lessons of extreme importance from the rough observations which suggested those old names. In these days, when observations of such marvellous exactness are daily and nightly made, when instruments capable of revealing the actual const.i.tution of the stars are employed, and observers are so numerous, it may seem strange to attach any interest to the question whether half-savage races recognised in such and such a star-group the likeness of a bear, or in another group the semblance of a s.h.i.+p. But though we could learn more, of course, from exacter observations, yet even such rough and imperfect records would have their value. If we could be certain that in long-past ages a star-group really resembled some known object, we should have in the present resemblance of that group to the same object evidence of the general constancy of stellar l.u.s.tre, or if no resemblance could be recognised we should have reason to doubt whether other suns (and therefore our own sun) may not be liable to great changes.

The subject of the constellation-figures as first known is interesting in other ways. For instance, it is full of interest to the antiquarian (and most of us are to some degree antiquarians) as relating to the most ancient of all human sciences. The same mental quality which causes us to look with interest on the buildings raised in long-past ages, or on the implements and weapons of antiquity, renders the thought impressive that the stars which we see were gazed on perhaps not less wonderingly in the very infancy of the human race. It is, again, a subject full of interest to the chronologist to inquire in what era of the world's history exact astronomy began, the moon was a.s.signed her twenty-eight zodiacal mansions, the sun his twelve zodiacal signs. It is well known, indeed, that Newton himself did not disdain to study the questions thus suggested; and the speculations of the ingenious Dupuis found favour with the great mathematician Laplace.

Unfortunately, the evidence is not sufficiently exact to be very trustworthy. In considering, for instance, the chronological inquiries of Newton, one cannot but feel that the reliance placed by him on the statements made by different writers is not justified by the nature of those statements, which were for the most part vague in the extreme. We owe many of them to poets who, knowing little of astronomy, mixed up the phenomena of their own time with those which they found recorded in the writings of astronomers. Some of the statements left by ancient writers are indeed ludicrously incongruous; insomuch that Grotius not unjustly said of the account of the constellations given by the poet Aratus, that it could be a.s.signed to no fixed epoch and to no fixed place. However, this would not be the place to discuss details such as are involved in exact inquiries. I have indicated some of these in an appendix to my treatise on 'Saturn,' and others in the preface to my 'Gnomonic Star Atlas'; but for the most part they do not admit very readily of familiar description. Let us turn to less technical considerations, which fortunately are in this case fully as much to the point as exact inquiries, seeing that there is no real foundation for such inquiries in any of the available evidence.

The first obvious feature of the old constellations is one which somehow has not received the attention it deserves. It is as instructive as any of those which have been made the subject of profound research.

There is a great s.p.a.ce in the heavens over which none of the old constellations extend, except the River Erida.n.u.s as now pictured, but we do not know where this winding stream of stars was supposed by the old observers to come to an end. This great s.p.a.ce surrounds the southern pole of the heavens, and thus shows that the first observers of the stars were not acquainted with the constellations which can be seen only from places far south of Chaldaea, Persia, Egypt, India, China, and indeed of all the regions to which the invention of astronomy has been a.s.signed. Whatever the first astronomers were, however profound their knowledge of astronomy may have been (as some imagine), they had certainly not travelled far enough towards the south to know the constellations around the southern pole. If they had been as well acquainted with geography as some a.s.sert, if even any astronomer had travelled as far south as the equator, we should certainly have had pictured in the old star charts some constellations in that region of the heavens wherein modern astronomers have placed the Octant, the Bird of Paradise, the Sword-fish, the Flying-fish, Toucan, the Net, and other uncelestial objects.

In pa.s.sing I may note that this fact disposes most completely of a theory lately advanced that the constellations were invented in the southern hemisphere, and that thus is to be explained the ancient tradition that the sun and stars have changed their courses. For though all the northern constellations would have been more or less visible from parts of the southern hemisphere near the equator, it is absurd to suppose that a southern observer would leave untenanted a full fourth of the heavens round the southern or visible pole, while carefully filling up the s.p.a.ce around the northern or unseen pole with incomplete constellations whose northern unknown portions would include that pole.

Supposing it for a moment to be true, as a modern advocate of the southern theory remarks, that 'one of the race migrating from one side to the other of the equator would take his position from the sun, and fancy he was facing the same way when he looked at it at noon, and so would think the motion of the stars to have altered instead of his having turned round,' the theory that astronomy was brought to us from south of the equator cannot possibly be admitted in presence of that enormous vacant region around the southern pole. I think, however, that, apart from this, a race so profoundly ignorant as to suppose any such thing, to imagine they were looking north when in reality they were looking south, can hardly be regarded as the first founders of the science of astronomy.

The great gap I have spoken of has long been recognised. But one remarkable feature in its position has not, to the best of my remembrance, been considered--the vacant s.p.a.ce is eccentric with regard to the southern pole of the heavens. The old constellations, the Altar, the Centaur, and the s.h.i.+p Argo, extend within twenty degrees of the pole, while the Southern Fish and the great sea-monster Cetus, which are the southernmost constellations on the other side, do not reach within some sixty degrees of the pole.

Of course, in saying that this peculiarity has not been considered, I am not suggesting that it has not been noticed, or that its cause is in any way doubtful or unknown. We know that the earth, besides whirling once a day on its axis, and rus.h.i.+ng on its mighty orbit around the sun (spanning some 184,000,000 of miles) reels like a gigantic top, with a motion so slow that 25,868 years are required for a single circuit of the swaying axis around an imaginary line upright to the plane in which the earth travels. And we know that in consequence of this reeling motion the points of the heavens opposite the earth's poles necessarily change. So that the southern pole, now eccentrically placed amid the region where there were no constellations in old times, was once differently situated. But the circ.u.mstance which seems to have been overlooked is this, that by calculating backwards to the time when the southern pole was in the centre of that vacant region, we have a much better chance of finding the date (let us rather say the century) when the older constellations were formed, than by any other process. We may be sure not to be led very far astray; for we are not guided by one constellation but by several, whereas all the other indications which have been followed depend on the supposed ancient position of single constellations. And then most of the other indications are such as might very well have belonged to periods following long after the invention of the constellations themselves. An astronomer might have ascertained, for instance, that the sun in spring was in some particular part of the Ram or of the Fishes, and later a poet like Aratus might describe that relation (erroneously for his own epoch) as characteristic of one or other constellation; but who is to a.s.sure us that the astronomer who noted the relation correctly may not have made his observation many hundreds of years after those constellations were invented? Whereas, there was one period, and only one period, when the most southernmost of the old constellations could have marked the limits of the region of sky visible from some northern region. Thus, too, may we form some idea of the lat.i.tude in which the first observers lived. For in high lat.i.tudes the southernmost of the old constellations would not have been visible at all, and in lat.i.tudes much lower than a certain lat.i.tude, presently to be noted, these constellations would have ridden high above the southern horizon, other star-groups showing below them which were not included among the old constellations.

I have before me as I write a picture of the southern heavens, drawn by myself, in which this vacant s.p.a.ce--eccentric in position but circular in shape--is shown. The centre lies close by the Lesser Magellanic cloud--between the stars Kappa Toucani and Eta Hydri of our modern maps, but much nearer to the last named. Near this spot, then, we may be sure, lay the southern pole of the star-sphere when the old constellations, or at least the southern ones, were invented. (If there had been astronomers in the southern hemisphere Eta Hydri would certainly have been their pole-star.)

Now it is a matter of no difficulty whatever to determine the epoch when the southern pole of the heavens was thus placed.[57] Between 2100 and 2200 years before the Christian era the southern constellations had the position described, the invisible southern pole lying at the centre of the vacant s.p.a.ce of the star-sphere--or rather of the s.p.a.ce free from constellations. It is noteworthy that for other reasons this period, or rather a definite epoch within it, is indicated as that to which must be referred the beginning of exact astronomy. Amongst others must be mentioned this--that in the year 2170 B.C. _quam proxime_, the Pleiades rose to their highest above the horizon at noon (or technically made their noon culmination), at the spring equinox. We can readily understand that to minds possessed with full faith in the influence of the stars on the earth, this fact would have great significance. The changes which are brought about at that season of the year, in reality, of course, because of the gradual increase in the effect of the sun's rays as he rises higher and higher above the celestial equator, would be attributed, in part at least, to the remarkable star-cl.u.s.ter coming then close by the sun on the heavens, though unseen. Thus we can readily understand the reference in Job to the 'sweet influences of the Pleiades.' Again at that same time, 2170 B.C. when the sun and the Pleiades opened the year (with commencing spring) together, the star Alpha of the Dragon, which was the pole-star of the period, had that precise position with respect to the true pole of the heavens which is indicated by the slope of the long pa.s.sage extending downwards aslant from the northern face of the Great Pyramid; that is to say, when due north below the pole (or at what is technically called its sub-polar meridional pa.s.sage) the pole-star of the period shone directly down that long pa.s.sage, and I doubt not could be seen not only when it came to that position during the night, but also when it came there during the day-time.

But some other singular relations are to be noted in connection with the particular epoch I have indicated.

It is tolerably clear that in imagining figures of certain objects in the heavens, the early observers would not be apt to picture these objects in unusual positions. A group of stars may form a figure so closely resembling that of a familiar object that even a wrong position would not prevent the resemblance from being noticed, as for instance the 'Chair,' the 'Plough,' and so forth. But such cases are not numerous; indeed, to say the truth, one must 'make believe a good deal'

to see resemblance between the star-groups and _most_ of the constellation-figures, even under the most favourable conditions. When there is no very close resemblance, as is the case with all the large constellations, position must have counted for something in determining the a.s.sociation between a star-group and a known object.

Now the constellations north of the equator a.s.sume so many and such various positions that this special consideration does not apply very forcibly to them. But those south of the equator are only seen above the southern horizon, and change little in position during their progress from east to west of the south point. The lower down they are the less they change in position. And the very lowest--such as those were, for instance, which I have been considering in determining the position of the southern pole--are only fully visible when due south. They must, then, in all probability, have stood upright or in their natural position when so placed, for if they were not rightly placed then they only were so when below the horizon and consequently invisible.

Let us, then, inquire what was the position of the southernmost constellations when fully seen above the southern horizon at midnight.

The Centaur stood then as he does now, upright; only--whereas now in Egypt, Chaldaea, India, Persia, and China, only the upper portions of his figure rise above the horizon, he then stood, the n.o.blest save Orion of all the constellations, with his feet (marked by the bright Alpha and Beta still belonging to the constellation, and by the stars of the Southern Cross which have been taken from it) upon the horizon itself.

In lat.i.tude twenty degrees or so north he may still be seen thus placed when due south.

The Centaur was represented in old times as placing an offering upon the altar, which was pictured, says Manilius, as bearing a fire of incense represented by stars. This to a student of our modern charts seems altogether perplexing. The Centaur carries the wolf on the end of his spear; but instead of placing the wolf (not a very acceptable meat offering, one would suppose) upon the altar, he is directing this animal towards the base of the altar, whose top is downwards, the flames represented there tending (naturally) downwards also. It is quite certain the ancient observers did not imagine anything of this sort. As I have said, Aratus tells us the celestial Centaur was placing an offering _upon_ the altar, which was therefore upright, and Manilius describes the altar as

Ferens thuris, stellis imitantibus, ignem,

so that the fire was where it should be, on the top of an upright altar, where also on the sky itself were stars looking like the smoke from incense fires. Now that was precisely the appearance presented by the stars forming the constellation at the time I have indicated, some 2170 years B.C. Setting the altar upright above the southern horizon (that is, inverting the absurd picture at present given of it) we see it just where it should be placed to receive the Centaur's offering. A most remarkable portion of the Milky Way is then seen to be directly above the altar in such a way as to form a very good imitation of smoke ascending from it. This part of the Milky Way is described by Sir J.

Herschel, who studied it carefully during his stay at the Cape of Good Hope, as forming a complicated system of interlaced streaks and ma.s.ses which covers the tail of Scorpio (extending from the altar which lies immediately south of the Scorpion's Tail). The Milky Way divides, in fact, just above the altar as the constellation was seen 4000 years ago above the southern horizon, one branch being that just described, the other (like another stream of smoke) 'pa.s.sing,' says Herschel, 'over the stars Iota of the Altar, Theta and Iota of the Scorpion, etc., to Gamma of the Archer, where it suddenly collects into a vivid oval ma.s.s, so very rich in stars that a very moderate calculation makes their number exceed 100,000.' Nothing could accord better with the descriptions of Aratus and Manilius.

But there is another constellation which shows in a more marked way than either the Centaur or the Altar that the date when the constellations were invented must have been near that which I have named. Both Ara and Centaurus look now in suitable lat.i.tudes (about twenty degrees north) as they looked in higher lat.i.tudes (about forty degrees north) 4000 years ago. For, the reeling motion of our earth has changed the place of the celestial pole in such a way as only to depress these constellations southwards without much changing their _position_; they are nearly upright when due south now as they were 4000 years ago, only lower down.

But the great s.h.i.+p Argo has suffered a much more serious displacement.

One cannot now see this s.h.i.+p _like_ a s.h.i.+p at any time or from any place on the earth's surface. If we travel south till the whole constellation comes into visibility above the southern horizon at the proper season (January and February for the midnight hours) the keel of the s.h.i.+p is aslant, the stern being high above the waist (the fore part is wanting).

If we travel still further south, we can indeed reach places where the course of the s.h.i.+p is so widened, and the changes of position so increased, that she appears along part of her journey on an even keel, but then she is high above the horizon. Now 4000 years ago she stood on the horizon itself at her southern culmination, with level keel and upright mast.

In pa.s.sing I may note that for my own part I imagine that this great s.h.i.+p represented the Ark, its fore part being originally the portion of the Centaur now forming the horse, so that the Centaur was represented as a man (not as a man-horse) offering a gift on the Altar. Thus in this group of constellations I recognise the Ark, and Noah going up from the Ark towards the altar 'which he builded unto the Lord; and took of every clean beast, and of every clean fowl, and offered burnt offerings on the altar.' I consider further that the constellation-figures of the s.h.i.+p, the Man with an offering, and the Altar, painted or sculptured in some ancient astrological temple, came at a later time to be understood as picturing a certain series of events, interpreted and expanded by a poetical writer into a complete narrative. Without venturing to insist on so heterodox a notion, I may remark as an odd coincidence that probably such a picture or sculpture would have shown the smoke ascending from the Altar which I have already described, and in this smoke there would be shown the bow of Sagittarius; which, interpreted and expanded in the way I have mentioned, might have accounted for the 'bow set in the clouds, for a token of a covenant.' It is noteworthy that all the remaining constellations forming the southern limit of the old star-domes or charts, were watery ones--the Southern Fish, over which Aquarius is pouring a quite unnecessary stream of water, the Great Sea Monster towards which in turn flow the streams of the River Erida.n.u.s. The equator, too, was then occupied along a great part of its length by the great sea serpent Hydra, which reared its head above the equator, very probably indicated then by a water horizon, for nearly all the signs below it were then watery. At any rate, as the length of Hydra then lay horizontally above the s.h.i.+p, whose masts reached it, we may well believe that this part of the picture of the heavens showed a sea-horizon and a s.h.i.+p, the great sea serpent lying along the horizon.

On the back of Hydra is the Raven, which again may be supposed by those who accept the theory mentioned above to have suggested the raven which went forth to and fro from the ark. He is close enough to the rigging of Argo to make an easy journey of it. The dove, however, must not be confounded with the modern constellation Columba, though this is placed (suitably enough) near the Ark. We must suppose the idea of the dove was suggested by a bird pictured in the rigging of the celestial s.h.i.+p. The sequence in which the constellations came above the horizon as the year went round corresponded very satisfactorily with the theory, fanciful though this seem to some. First Aquarius pouring streams of water, the three fishes (Pisces and Piscis australis), and the great sea monster Cetus, showing how the waters prevailed over the highest hills, then the Ark sailing on the waters, a little later the Raven (Corvus), the man descending from the ark and offering a gift on the Altar, and last the Bow set amid the clouds.

The theory just described may not meet with much favour. But wilder theories of the story of the deluge have been adopted and advocated with considerable confidence. One of the wildest, I fear, is the Astronomer-Royal's, that the deluge was simply a great rising of the Nile; and Sir G. Airy is so confident respecting this that he says, 'I cannot entertain the smallest doubt that the flood of Noah was a flood of the Nile;' precisely as he might say, 'I cannot entertain the smallest doubt that the earth moves round the sun.' On one point we can entertain very little doubt indeed. If it ever rained before the flood, which seems probable, and if the sun ever shone on falling rain, which again seems likely, nothing short of a miracle could have prevented the rainbow from making its appearance before the flood. The wildest theory that can be invented to explain the story of the deluge cannot be wilder than the supposition that the rays of sunlight s.h.i.+ning on falling raindrops could have ever failed to show the prismatic colours. The theory I have suggested above, without going so far as strongly to advocate it, far less insist upon it, is free at any rate from objection on this particular score, which cannot be said of the ordinary theory. I am not yet able, however, to say that 'I cannot entertain the smallest doubt' about my theory.

We may feel tolerably sure that the period when the old southern constellations were formed must have been between 2400 and 2000 years before the present era, a period, by the way, including the date usually a.s.signed to the deluge,--which, however, must really occupy our attention no further. In fact, let us leave the watery constellations lying below the equator of those remote times and seek at once the highest heavens above them.

Here, at the northern pole of these days, we find the great Dragon, which in any astrological temple of the time must have formed the highest or crowning constellation, surrounding the very key-stone of the dome. He has fallen away from that proud position since. In fact, even 4000 years ago he only held to the pole, so to speak, by his tail, and we have to travel back 2000 years or so to find the pole situate in a portion of the length of the Dragon which can be regarded as central.

One might almost, if fancifully disposed, recognise the gradual displacement of the Dragon from his old place of honour, in certain traditions of the downfall of the great Dragon whose 'tail drew the third part of the stars of heaven.'

The central position of the Dragon, for even when the pole-star had drawn near to the Dragon's tail the constellation was still central, will remind the cla.s.sical reader of Homer's description of the s.h.i.+eld of Hercules--

The scaly horror of a dragon, coil'd Full in the central field, unspeakable, With eyes oblique retorted, that ascant Shot gleaming fire. (_Elton's translation._)

I say Homer's description, for I cannot understand how any one who compares together the description of the s.h.i.+eld of Achilles in the Iliad and that of the s.h.i.+eld of Hercules in the fragmentary form in which we have it, can doubt for a moment that both descriptions came from the same hand. (The theory that Hesiod composed the latter poem can scarcely be entertained by any scholar.) As I long since pointed out in my essay 'A New Theory of Achilles' s.h.i.+eld' ('Light Science,' first series), no poet so inferior as actually to borrow Homer's words in part of the description of the s.h.i.+eld of Hercules could have written the other parts not found in the s.h.i.+eld of Achilles. 'I cannot for my own part entertain the slightest doubt'--that is to say, I think it altogether probable--that Homer composed the lines supposed to describe the s.h.i.+eld of Hercules long before he introduced the description, pruned and strengthened, into that particular part of the Iliad where it served his purpose best. And I have as little doubt that the original description, of which we only get fragments in either poem, related to something far more important than a s.h.i.+eld. The constellations are not suitable adornments for the s.h.i.+eld of fighting man, even though he was under the special care of a celestial mother and had armour made for him by a celestial smith. Yet we learn that Achilles' s.h.i.+eld displayed--

The starry lights that heav'n's high convex crown'd The Pleiads, Hyads, and the northern beam, And great Orion's more refulgent beam,-- To which, around the cycle of the sky, The bear revolving, points his golden eye,-- Still s.h.i.+nes exalted.

And so forth. The s.h.i.+eld of Hercules displayed at its centre the polar constellation the Dragon. We read also that--

There was the knight of fair-hair'd Danae born, Perseus.

Orion is not specially mentioned, but Orion, Lepus, and the Dogs seem referred to:--