CHAPTER XII.

ECLIPSES AND COMETS.

We have seen in the earlier chapters on the systems of the ancients and their ideas of the world how everything was once supposed to have exclusive reference to man, and how he considered himself not only chief of animate objects, but that his own city was the centre of the material world, and his own world the centre of the material universe; that the sun was made to shine, as well as the moon and stars, for his benefit; and that, were it not for him they would have no reason for existence. And we have seen how, step by step, these illusions have been dispelled, and he has learnt to appreciate his own littleness in proportion as he has realised the immensity of the universe of which he forms part.

If such has been his history, and such his former ideas on the regular parts, as we may call them, of nature, much more have similar ideas been developed in relation to those other phenomena which, coming at such long intervals, have not been recognised by him as periodic, but have seemed to have some relation to mundane affairs, often of the smallest consequence. Such are eclipses of the sun and moon, comets, shooting-stars, and meteors. Among the less instructed of men, even when astronomers of the same age and nation knew their real nature, eclipses have always been looked upon as something ominous of evil.

Among the ancient nations people used to come to the assistance of the moon, by making a confused noise with all kinds of instruments, when it was eclipsed. It is even done now in Persia and some parts of China, where they fancy that the moon is fighting with a great dragon, and they think the noise will make him loose his hold and take to flight. Among the East Indians they have the same belief that when the sun and the moon are eclipsed, a dragon is seizing them, and astronomers who go there to observe eclipses are troubled by the fears of their native attendants, and by their endeavours to get into the water as the best place under the circumstances. In America the idea is that the sun and moon are tired when they are eclipsed. But the more refined Greeks believed for a long time that the moon was bewitched, and that the magicians made it descend from heaven, to put into the herbs a certain maleficent froth. Perhaps the idea of the Dragon arose from the ancient custom of calling the places in the heavens at which the eclipses of the moon took place the head and tail of the Dragon.

In ancient history we have many curious instances of the very critical influence that eclipses have had, especially in the case of events in a campaign, where it was thought unfavourable to some projected attempt.

Thus an eclipse of the moon was the original cause of the death of the Athenian general Nicias. Just at a critical juncture, when he was about to depart from the harbour of Syracuse, the eclipse filled him and his whole army with dismay. The result of his terror was that he delayed the departure of his fleet, and the Athenian army was cut in pieces and destroyed, and Nicias lost his liberty and life.

Plutarch says they could understand well enough the cause of the eclipse of the sun by the interposition of the moon, but they could not imagine by the opposition of what body the moon itself could be eclipsed.

One of the most famous eclipses of antiquity was that of Thales, recorded by Herodotus, who says:--"The Lydians and the Medes were at war for five consecutive years. Now while the war was sustained on both sides with equal chance, in the sixth year, one day when the armies were in battle array, it happened that in the midst of the combat the day suddenly changed into night. Thales of Miletus had predicted this phenomenon to the Ionians, and had pointed out precisely that very year as the one in which it would take place. The Lydians and Medes, seeing the night succeeding suddenly to the day, put an end to the combat, and only cared to establish peace."

Another notable eclipse is that related by Diodorus Siculus. It was a total eclipse of the sun, which took place while Agathocles, fleeing from the port of Syracuse, where he was blockaded by the Carthaginians, was hastening to gain the coast of Africa. "When Agathocles was already surrounded by the enemy, night came on, and he escaped contrary to all hope. On the day following so complete an eclipse of the sun took place that it seemed altogether night, for the stars shone out in all places. The soldiers therefore of Agathocles, persuaded that the gods were intending them some misfortune, were in the greatest perturbation about the future. Agathocles was equal to the occasion. When disembarked in Africa, where, in spite of all his fine words, he was unable to reassure his soldiers, whom the eclipse of the sun had frightened, he changed his tactics, and pretending to understand the prodigy, "I grant, comrades," he said, "that had we perceived this, eclipse before our embarkation we should indeed have been in a critical situation, but now that we have seen it after our departure, and as it always signifies a change in the present state of affairs, it follows that our circumstances, which were very bad in Sicily, are about to amend, while we shall indubitably ruin those of the Carthaginians, which have been hitherto so flourishing."

We are reminded by this of the story of Pericles, who, when ready to set sail with his fleet on a great expedition, saw himself stopped by a similar phenomenon. He spread his mantle over the eyes of the pilot, whom fear had prevented acting, and asked him if that was any sign of misfortune, when the pilot answered in the negative. "What misfortune then do you suppose," said he, "is presaged by the body that hides the sun, which differs from this in nothing but being larger?"

With reference to these eclipses, when their locality and approximate date is known, astronomy comes to the assistance of history, and can supply the exact day, and even hour, of the occurrence. For the eclipses depend on the motions of the moon, and just as astronomers can calculate both the time and the path of a solar eclipse in the future, so they can for the past. If then the eclipses are calculated back to the epoch when the particular one is recorded, it can be easily ascertained which one it was that about that time passed over the spot at which it was observed, and as soon as the particular eclipse is fixed upon, it may be told at what hour it would be seen.

Thus the eclipse of Thales has been assigned by different authors to various dates, between the 1st of October, 583 B.C., and the 3rd of February, 626 B.C. The only eclipse of the sun that is suitable between those dates has been found by the Astronomer-Royal to be that which would happen in Lydia on the 28th of May, 585 B.C., which must therefore be the date of the event.

So of the eclipse of Agathocles, M. Delaunay has fixed its date to the 15th August, 310 B.C.

In later days, when Christopher Columbus had to deal with the ignorant people of America, the same kind of story was repeated. He found himself reduced to famine by the inhabitants of the country, who kept him and his companions prisoners; and being aware of the approach of the eclipse, he menaced them with bringing upon them great misfortunes, and depriving them of the light of the moon, if they did not instantly bring him provisions. They cared little for his menaces at first; but as soon as they saw the moon disappear, they ran to him with abundance of victuals, and implored pardon of the conqueror. This was on the 1st of March, 1504, a date which may be tested by the modern tables of the moon, and Columbus's account proved to be correct. The eclipse was indeed recorded in other places by various observers.

Eclipses in their natural aspect have thus had considerable influence on the vulgar, who knew nothing of their cause. This of course was the state with all in the early ages, and it is interesting to trace the gradual progress from their being quite unexpected to their being predicted.

It is very probable, if not certain, that their recurrence in the case of the moon at least was recognised long before their nature was understood.

Among the Chinese they were long calculated, and, in fact, it is thought by some that they have pretended to a greater antiquity by calculating backwards, and recording as observed eclipses those which happened before they understood or noticed them. It seems, however, authenticated that they did in the year 2169 B.C. observe an eclipse of the sun, and that at that date they were in the habit of predicting them. For this particular eclipse is said to have cost several of the astronomers their lives, as they had not calculated it rightly. As the lives of princes were supposed to be dependent on these eclipses, it became high treason to expose them to such a danger without forewarning them. They paid more attention to the eclipses of the sun than of the moon.

Among the Babylonians the eclipses of the moon were observed from a very early date, and numerous records of them are contained in the Observations of Bel in Sargon's library, the tablets of which have lately been discovered. In the older portion they only record that on the 14th day of such and such a (lunar) month an eclipse takes place, and state in what watch it begins, and when it ends. In a later portion the observations were more precise, and the descriptions of the eclipse more accurate. Long before 1700 B.C. the discovery of the lunar cycle of 223 lunar months had been made, and by means of it they were able to state of each lunar eclipse, that it was either "according to calculation" or "contrary to calculation."

They dealt also with solar eclipses, and tried to trace on a sphere the path they would take on the earth. Accordingly, like the eclipses of the moon, these too were spoken of as happening either "according to calculation" or "contrary to calculation." "In a report sent in to one of the later kings of Assyria by the state astronomer, Abil Islar states that a watch had been kept on the 28th, 29th, and 30th of Sivan, or May, for an eclipse of the sun, which did not, however, take place after all. The shadow, it is clear, must have fallen outside the field of observation." Besides the more ordinary kind of solar eclipses, mention is made in the Observations of Bel of annular eclipses which, strangely enough, are seldom alluded to by classical writers.

A record of a later eclipse has been found by Sir Henry Rawlinson on one of the Nineveh Tablets. This occurred near that city in B.C. 763, and from the character of the inscription it may be inferred that it was a rare occurrence with them, indeed that it was nearly, if not quite, a total eclipse. This has an especial interest as being the earliest that we have any approximate date for.

It is possible that the remarkable phenomenon, alluded to by the prophet Isaiah, of the shadow going backwards ten degrees on the dial of Ahaz, may be really a record of an eclipse of the sun, such as astronomy proves to have occurred at Jerusalem in the year 689 B.C.

We have very little notice of the calculation of eclipses by the Egyptians; all that is told us is more or less fabulous. Thus Diogenes Laertius says that they reckoned that during a period of 48,863 years, 373 eclipses of the sun and 832 eclipses of the moon had occurred, which is far fewer than the right number for so long a time, and which, of course, has no basis in fact.

Among the Greeks, Anaxagoras was the first who entertained clear ideas about the nature of eclipses; and it was from him that Pericles learnt their harmlessness.

Plutarch relates that Helicon of Cyzicus predicted an eclipse of the sun to Dionysius of Syracuse, and received as a reward a talent of silver.

Livy records an eclipse of the sun as having taken place on the 11th of Quintilis, which corresponds to the 11th of July. It happened during the Appollinarian games, 190 B.C.

The same author tells us of an eclipse of the moon that was predicted by one Gallus, a tribune of the second legion, on the eve of the battle of Pydna--a prediction which was duly fulfilled on the following night. The fact of its having been foretold quieted the superstitious fears of the soldiers, and gave them a very high opinion of Gallus. Other authors, among them Cicero, do not give so flattering a story, but state that Gallus's part consisted only in explaining the cause of the eclipse after it had happened. The date of this eclipse was the 3rd of September, 168 B.C.

Ennius, writing towards the end of the second century B.C., describes an eclipse which was said to have happened nearly two hundred years before (404, B.C.), in the following remarkable words:--"On the nones of July the moon passed over the sun, and there was night." Aristarchus, three centuries before Christ, understood and explained the nature of eclipses; but the chief of the ancient authors upon this subject was Hipparchus. He and his disciples were able to predict eclipses with considerable accuracy, both as to their time and duration. Geminus and Cleomedes were two other writers, somewhat later, who explained and predicted eclipses. In later times regular tables were drawn up, showing when the eclipses would happen. One that Ptolemy was the author of was founded on data derived from ancient observers--Callipus, Democritus, Eudoxus, Hipparchus--aided by his own calculations. After the days of Ptolemy the knowledge of the eclipses advanced _pari passu_ with the advance of astronomy generally. So long as astronomy itself was empirical, the time of the return of an eclipse was only reckoned by the intervals that had elapsed during the same portion of previous cycles; but after the discovery of elliptic orbits and the force of gravitation the whole motion of the moon could be calculated with as great accuracy as any other astronomical phenomenon.

In point of fact, if the new moon is in the plane of the ecliptic there must be an eclipse of the sun; if the full moon is there, there must be an eclipse of the moon; and if it should in these cases be only partially in that plane, the eclipses also will be partial. The cycle of changes that the position of the moon can undergo when new and full occupies a period of eighteen years and eleven days, in which period there are forty-one eclipses of the sun and twenty-nine of the moon. Each year there are at most seven and at least two eclipses; if only two, they are eclipses of the sun. Although more numerous in reality for the whole earth, eclipses of the sun are more rarely observed in any particular place, because they are not seen everywhere, but only where the shadow of the moon passes; while all that part of the earth that sees the moon at all at the time sees it eclipsed.

We now come to comets.

The ancients divided comets into different classes, the chief points of distinction being derived from the shape, length, and brilliancy of the tails. Pliny distinguished twelve kinds, which he thus characterised:--"Some frighten us by their blood-coloured mane; their bristling hair rises towards the heaven. The bearded ones let their long hair fall down like a majestic beard. The javelin-shaped ones seem to be projected forwards like a dart, as they rapidly attain their shape after their first appearance; if the tail is shorter, and terminates in a point, it is called a sword; this is the palest of all the comets; it has the appearance of a bright sword without any diverging rays. The plate or disc derives its name from its shape, its colour is that of amber, it gives out some diverging rays from its sides, but not in large quantity. The cask has really the form of a cask, which one might suppose to be staved in smoke enveloped in light. The retort imitates the figure of a horn, and the lamp that of a burning flame. The horse-comet represents the mane of a horse which is violently agitated, as by a circular, or rather cylindrical, motion. Such a comet appears also of singular whiteness, with hair of a silver hue; it is so bright that one can scarcely look at it. There are bristling comets, they are like the skins of beasts with their hair on, and are surrounded by a nebulosity. Lastly, the hair of the comet sometimes takes the form of a lance."

Pingre, a celebrated historian of comets, tells us that one of the first comets noticed in history is that which appeared over Rome forty years before Christ, and in which the Roman people imagined they saw the soul of Caesar endowed with divine honours. Next comes that which threw its light on Jerusalem when it was being besieged and remained for a whole year above the city, according to the account of Josephus. It was of this kind that Pliny said it "is of so great a whiteness that one can scarcely look at it, and _one may see in it the image of God in human form_."

Diodorus tells us that, a little after the subversion of the towns of Helix and Bura, there were seen, for several nights in succession, a brilliant light, which was called a beam of fire, but which Aristotle says was a true comet.

Plutarch, in his life of Timoleon, says a burning flame preceded the fleet of this general until his arrival at Sicily, and that during the consulate of Caius Servilius a bright shield was seen suspended in the heavens.

The historians Sazoncenas and Socrates relate that in the year 400 A.D. a comet in the form of a sword shone over Constantinople, and appeared to touch the town just at the time when great misfortunes were impending through the treachery of Gainas.

The same phenomenon appeared over Rome previous to the arrival of Alaric.

In fact the ancient chroniclers always associated the appearance of a comet with some terrestrial event, which it was not difficult to do, seeing that critical situations were at all times existing in some one country or other where the comet would be visible, and probably those which could not be connected with any were not thought worthy of being recorded.

It is well known that the year 1000 A.D. was for a long time predicted to be the end of the world. In this year the astronomers and chroniclers registered the fall of an enormous burning meteor and the appearance of a comet. Pingre says: "On the 19th of the calends of January"--that is the 14th of December--"the heavens being dark, a kind of burning sword fell to the earth, leaving behind it a long train of light. Its brilliancy was such that it frightened not only those who were in the fields, but even those who were shut up in their houses. This great opening in the heavens was gradually closed, and then was seen the figure of a dragon, whose feet were blue, and whose head kept continually increasing. A comet having appeared at the same time as this chasm, or meteor, they were confounded." This relation is given in the chronicles of Seigbert in Hermann Corner, in the Chronique de Tours, in Albert Casin, and other historians of the time.

Bodin, resuscitating an idea of Democritus, wrote that the comets were the souls of illustrious personages, who, after having lived on the earth a long series of centuries, and being ready at last to pass away, were carried in a kind of triumph to heaven. For this reason, famine, epidemics, and civil wars followed on the apparition of comets, the towns and their inhabitants finding themselves then deprived of the help of the illustrious souls who had laboured to appease their intestinal feuds.

One of the comets of the middle ages which made the greatest impression on the minds of the people was that which appeared during Holy Week of the year 837, and frightened Louis the Debonnaire. The first morning of its appearance he sent for his astrologer. "Go," he said, "on to the terrace of the palace, and come back again immediately and tell me what you have seen, for I have not seen that star before, and you have not shown it to me; but I know that this sign is a comet: it announces a change of reign and the death of a prince." The son of Charlemagne having taken counsel with his bench of bishops, was convinced that the comet was a notice sent from heaven expressly for him. He passed the nights in prayer, and gave large donations to the monasteries, and finally had a number of masses performed out of fear for himself and forethought for the Church committed to his care. The comet, however, was a very inoffensive one, being none other than that known as Halley's comet, which returned in 1835. While they were being thus frightened in France, the Chinese were observing it astronomically.

The historian of Merlin the enchanter relates that a few days after the _fetes_ which were held on the occasion of the erection of the funeral monument of Salisbury, a sign appeared in heaven. It was a comet of large size and excessive splendour. It resembled a dragon, out of whose mouth came a long two-forked tongue, one part of which turned towards the north and the other to the east. The people were in a state of fear, each one asking what this sign presaged. Uter, in the absence of the king, Ambrosius, his brother, who was engaged in pursuing one of the sons of Vortigern, consulted all the wise men of Britain, but no one could give him any answer. Then he thought of Merlin the enchanter, and sent for him to the court. "What does this apparition presage?" demanded the king's brother. Merlin began to weep. "O son of Britain, you have just had a great loss--the king is dead." After a moment of silence he added, "But the Britons have still a king. Haste thee, Uter, attack the enemy. All the island will submit to you, for the figure of the fiery dragon is thyself. The ray that goes towards Gaul represents a son who shall be born to thee, who will be great by his achievements, and not less so by his power. The ray that goes towards Ireland represents a daughter of whom thou shalt be the father, and her sons and grandsons shall reign over all the Britons." These predictions were realised; but it is more than probable that they were made up after the event.

The comet of 1066 was regarded as a presage of the Conquest under William of Normandy. In the Bayeaux tapestry, on which Matilda of Flanders had drawn all the most memorable episodes in the transmarine expedition of her husband, the comet appears in one of the corners with the inscription, _Isti mirantur stellam_, which proves that the comet was considered a veritable marvel. It is said even to be traditionally reported that one of the jewels of the British crown was taken from the tail of this comet. Nevertheless it was no more than Halley's comet again in its periodical visit every seventy-six years.

In July, 1214, a brilliant comet appeared which was lost to view on the same day as the Pope, Urban IV., died, _i.e._ the third of October.

In June, 1456, a similar body of enormous size, with a very long and extraordinarily bright tail, put all Christendom in a fright. The Pope, Calixtus III., was engaged in a war at that time with the Saracens. He showed the Christians that the comet "had the form of a cross," and announced some great event. At the same time Mahomet announced to his followers that the comet, "having the form of a yataghan," was a blessing of the Prophet's. It is said that the Pope afterwards recognised that it had this form, and excommunicated it. Nevertheless, the Christians obtained the victory under the walls of Belgrade. This was another appearance of Halley's comet.

In the early months of 1472 appeared a large comet, which historians agree in saying was very horrible and alarming. Belleforest said it was a hideous and frightening comet, which threw its rays from east to west, giving great cause for fear to great people, who were not ignorant that comets are the menacing rods of God, which admonish those who are in authority, that they may be converted.

Pingre, who has told us of so many of the comets that were seen before his time, wrote of this epoch: "Comets became the most efficacious signs of the most important and doubtful events. They were charged to announce wars, seditions, and the internal movements of republics; they presaged famines, pestilence, and epidemics; princes, or even persons of dignity, could not pay the tribute of nature without the previous appearance of that universal oracle, a comet; men could no longer be surprised by any unexpected event; the future might be as easily read in the heavens as the past in history. Their effect depended on the place in the heavens where they shone, the countries over which they directly lay, the signs of the zodiac that they measured by their longitude, the constellations they traversed, the form and length of their tails, the place where they went out, and a thousand other circumstances more easily indicated than distinguished; they also announced in general wars, and the death of princes, or some grand personage, but there were few years that passed without something of this kind occurring. The devout astrologers--for there were many of that sort--risked less than the others. According to them, the comet threatened some misfortune; if it did not happen, it was because the prayers of penitence had turned aside the wrath of God; he had returned his sword to the scabbard. But a rule was invented which gave the astrologers free scope, for they said that events announced by a comet might be postponed for one or more periods of forty years, or even as many years as the comet had appeared days; so that one which had appeared for six months need not produce its effect for 180 years."

The most frightful of the comets of this period, according to Simon Goulart, was that of 1527. "It put some into so great a fright that they died; others fell sick. It was seen by several thousand people, and appeared very long, and of the colour of blood. At the summit was seen the representation of a curved arm, holding a large sword in its hand, as if it would strike; at the top of the point of the sword were three stars, but that which touched the point was more brilliant than the others. On the two sides of the rays of this comet were seen large hatchets, poignards, bloody swords, among which were seen a great number of men decapitated, having their heads and beards horribly bristling."

A view of this comet is given in the _History of Prodigies_.

There was another comet remarked in 1556, and another in 1577, like the head of an owl, followed by a mantle of scattered light, with pointed ends. Of this comet we read in the same book that recorded the last described: "The comet is an infallible sign of a very evil event. Whenever eclipses of the sun or moon, or comets, or earthquakes, conversions of water into blood, and such like prodigies happen, it has always been known that very soon after these miserable portents afflictions, effusion of human blood, massacres, deaths of great monarchs, kings, princes, and rulers, seditions, treacheries, raids, overthrowings of empires, kingdoms, or villages; hunger and scarcity of provisions, burning and overthrowing of towns; pestilences, widespread mortality, both of beasts and men; in fact all sorts of evils and misfortunes take place. Nor can it be doubted that all these signs and prodigies give warning that the end of the world is come, and with it the terrible last judgment of God."

But even now comets were being observed astronomically, and began to lose their sepulchral aspect.

A remarkable comet, however, which appeared in 1680, was not without its fears for the vulgar. We are told that it was recognised as the same which appeared the year of Caesar's death, then in 531, and afterwards in 1106, having a period of about 575 years. The terror it produced in the towns was great; timid spirits saw in it the sign of a new deluge, as they said water was always announced by fire. While the fearful were making their wills, and, in anticipation of the end of the world, were leaving their money to the monks, who in accepting them showed themselves better physicists than the testators, people in high station were asking what great person it heralded the death of, and it is reported of the brother of Louis XIV., who apparently was afraid of becoming too suddenly like Caesar, that he said sharply to the courtiers who were discussing it, "Ah, gentlemen, you may talk at your ease, if you please; you are not princes."

This same comet gave rise to a curious story of an "extraordinary prodigy, how at Rome a hen laid an egg on which was drawn a picture of the comet.

"The fact was attested by his Holiness, by the Queen of Sweden, and all the persons of first quality in Rome. On the 4th December, 1680, a hen laid an egg on which was seen the figure of the comet, accompanied by other marks such as are here represented. The cleverest naturalists in Rome have seen and examined it, and have never seen such a prodigy before."

Of this same comet Bernouilli wrote, "_That if the body of the comet is not a visible sign of the anger of God, the tail may be_." It was this too that suggested to Whiston the idea that he put forward, not as a superstitious, but as a physical speculation, that a comet approaching the earth was the cause of the deluge.

The last blow to the superstitious fear of the comets was given by Halley, when he proved that they circulated like planets round the sun, and that the comets noticed in 837, 1066, 1378, 1456, 1531, 1607, 1682 were all one, whose period was about 76 years, and which would return in 1759, which prediction was verified, and the comet went afterwards by the name of this astronomer. It returned again in 1835, and will revisit us in 1911.

Even after the fear arising from the relics of astrology had died away, another totally different alarm was connected with comets--an alarm which has not entirely subsided even in our own times. This is that a comet may come in contact with the earth and destroy it by the collision. The most remarkable panic in this respect was that which arose in Paris in 1773. At the previous meeting of the Academy of Sciences, M. Lalande was to have read an interesting paper, but the time failed. It was on the subject of comets that could, by approaching the earth, cause its destruction, with special reference to the one that was soon to come. From the title only of the paper the most dreadful fears were spread abroad, and, increasing day by day, were with great difficulty allayed. The house of M. Lalande was filled with those who came to question him on the memoir in question. The fermentation was so great that some devout people, as ignorant as weak, asked the archbishop to make a forty hours' prayer to turn away the enormous deluge that they feared, and the prelate was nearly going to order these prayers, if the members of the Academy had not persuaded him how ridiculous it would be. Finally, M. Lalande, finding it impossible to answer all the questions put to him about his fatal memoir, and wishing to prevent the real evils that might arise from the frightened imaginations of the weak, caused it to be printed, and made it as clear as was possible. When it appeared, it was found that he stated that of the sixty comets known there were eight which could, by coming too near the earth, say within 40,000 miles, occasion such a pressure that the sea would leave its bed and cover part of the globe, but that in any case this could not happen till after twenty years. This was too long to make it worth while to make provision for it, and the effervescence subsided.

A similar case to this occurred with respect to Biela's comet, which was to return in 1832. In calculating its reappearance in this year, Damoiseau found that it would pass through the plane of the earth's orbit on the 29th of October. Rushing away with this, the papers made out that a collision was inevitable, and the end of the world was come. But no one thought to inquire where the earth would be when the comet passed through the plane in which it revolved. Arago, however, set people's minds at rest by pointing out that at that time the earth would be a month's journey from the spot, which with the rate at which the earth is moving would correspond to a distance of sixty millions of miles.

This, like other frights, passed away, but was repeated again in 1840 and 1857 with like results, and even in 1872 a similar end to the world was announced to the public for the 12th of August, on the supposed authority of a Professor at Geneva, but who had never said what was supposed.

But in reality all cause of fear has now passed away, since it has been proved that the comet is made of gaseous matter in a state of extreme tenuity, so that, though it may make great show in the heavens, the whole mass may not weigh more than a few pounds; and we have in addition the testimony of experience, which might have been relied on on the occasions above referred to, for in 1770 Lexele's comet was seen to pass through the satellites of Jupiter without deranging them in the least, but was itself thrown entirely out of its path, while there is reason to believe that on the 29th of June, 1861, the earth remained several hours in the tail of a comet without having experienced the slightest inconvenience.

As to the nature of comets, the opinions that have been held have been mostly very vague. Metrodorus thought they were reflections from the sun; Democritus, a concourse of several stars; Aristotle, a collection of exhalations which had become dry and inflamed; Strabo, that they are the splendour of a star enveloped in a cloud; Heracletes of Pontus, an elevated cloud which gave out much light; Epigenes, some terrestrial matter that had caught fire, and was agitated by the wind; Boecius, part of the air, coloured; Anaxagoras, sparks fallen from the elementary fire; Xenophanes, a motion and spreading out of clouds which caught fire; and Descartes, the debris of vortices that had been destroyed, the fragments of which were coming towards us.

It is said that the Chaldaeans held the opinion that they were analogous to planets by their regular course, and that when we ceased to see them, it was because they had gone too far from us; and Seneca followed this explanation, since he regarded them as globes turning in the heavens, and which appear and disappear in certain times, and whose periodical motions might be known by regular observation.

We have thus traced the particular ideas that have attached themselves to eclipses and comets, as the two most remarkable of the extraordinary phenomena of the heavens, and have seen how the fears and superstitions of mankind have been inevitably linked with them in the earlier days of ignorance and darkness, but they are only part of a system of phenomena, and have been no more connected with superstition than others less remarkable, except in proportion to their remarkableness. Other minor appearances that are at all unusual have, on the same belief in the inextricable union of celestial and terrestrial matters, been made the signs of calamities or extra-prosperity; the doleful side of human nature being usually the strongest, the former have been chosen more often than the latter.

According to Seneca, the tradition of the Chaldees announced that a universal deluge would be caused by the conjunction of all the planets in the sign of Capricorn, and that a general breaking up of the earth would take place at the moment of their conjunction in Cancer. "The general break-up of the world," they said, "will happen when the stars which govern the heaven, penetrated with a quality of heat and dryness, meet one another in a fiery triplicity."

Everywhere, and in all ages of the past, men have thought that a protecting providence, always watching over them, has taken care to warn them of the destinies which await them; thence the good and evil _presages_ taken from the appearance of certain heavenly bodies, of divers meteors, or even the accidental meeting of certain animate or inanimate objects. The Indian of North America dying of famine in his miserable cabin, will not go out to the chase if he sees certain presages in the atmosphere. Nor need we be astonished at such ideas in an uncultivated man, when even among Europeans, a salt-cellar upset, a glass broken, a knife and fork crossed, the number thirteen at dinner, and such things are regarded as unlucky accidents. The employment of sorcery and divination is closely connected with these superstitions. Besides eclipses and comets, meteors were taken as the signs of divine wrath. We learn from S. Maximus of Turin, that the Christians of his time admitted the necessity of making a noise during eclipses, so as to prevent the magicians from hurting the sun or moon, a superstition entirely pagan. They used to fancy they could see celestial armies in the air, coming to bring miraculous assistance to man. They thought the hurricanes and tempests the work of evil spirits, whose rage kept them set against the earth. S. Thomas Aquinas, the great theologian of the thirteenth century, accepted this opinion, just as he admitted the reality of sorceries. But the full development, as well as the nourishment of these superstitious ideas, was derived from the storehouse of astrology, which dealt with matters of ordinary occurrence, both in the heavens and on the earth--and to the history of which our next chapter is devoted.