CHAPTER V. HISTORICAL NOTICES. Opinions of the Ancients on the nature of Comets.—Superstitious notions associated with them.-Extracts from ancient Chronicles.-Pope Calixtus III. and the Comet of 1456.-Extracts from the writings of English authors of the 16th and 17th centuries.—Napoleon and the Comet of 1769.—Supposed allusions in the Bible to Comets.-Conclusion. Go OING back to the early ages of the world, we find that the Chaldæans considered comets to be permanent bodies analogous to planets, but revolving round the Sun in orbits so much more extensive, that they were therefore only visible when near the Earth. This opinion, which, by the by, is the earliest hint that we have of the existence of periodical comets, was also held by philosophers of the Pythagorean school. Yet Aristotle, who records this, insists that comets are merely mundane exhalations, carried up into the atmosphere, and there ignited. Anaxagoras, Apollonius, Democritus, and Zeno considered that these bodies were aggregations of many small planets. It is a somewhat remarkable fact, that Ptolemy, so celebrated for his varied astronomical attainments, should nowhere have made any mention of comets; his omission is, however, atoned for by Pliny, who seems to have paid much attention to them. He enumerates 12 kinds, each class receiving its name from some physical peculiarity of the objects belonging to it. Seneca considered that comets must be above [i.e. beyond] the Moon, and he judged from their rising and setting, that they had something in common with the stars. Paracelsus gravely insisted that comets were celestial messengers, sent to foretell good or bad events-an idea which, even in the present day, has by no means died out. The ancient Romans did not trouble themselves much about astral phenomena; they nevertheless looked upon the comet of 43 B.C. as a celestial chariot carrying away the soul of Julius Cæsar, who had been assassinated shortly before it made its appear ance. In an ancient Norman Chronicle there occurs a curious exposition of the divine right of William I. to invade England:"How a star with 3 long tails appeared in the sky; how the learned declared that stars only appeared when a kingdom wanted a king, and how the said star was called a comette." Another old chronicler, speaking of the year 1060, says: "Soon after [the death of Henry, King of France, by poison], a comet denoting, as they say, change in kingdoms-appeared, trailing its extended and fiery train along the sky. Wherefore, a certain monk of our monastery, by name Elmer, bowing down with terror at the sight of the brilliant star, wisely exclaimed, ‘Thou art come! a matter of lamentation to many a mother art thou come; I have seen thee long since; but I now behold thee much more terrible, threatening to hurl destruction on this country "." 999 The superstitious dread in which comets were held during the Middle Ages is well exemplified in the case of the comet of 1456 (Halley's). We find that the then Pope, Calixtus III., ordered the Church bells to be rung daily at noon, and extra Ave Marias to be repeated by everybody. Whilst the comet was still visible Hunniades, the Hungarian general, gained an advantage over Mahomet II., and compelled him to raise the siege of Belgrade, the remembrance of which the Pope preserved by ordering the Festival of the Transfiguration, the anniversary of which was kept a few days after the battle, to be observed throughout Christendom with additional solemnities. "Thus was established the custom, which still exists in Romish countries, of ringing the Will. Malmes., De gestis Regum Angliæ, lib. ii. cap. 225. bells at noon; and perhaps it is from this circumstance that the well-known cakes made of sliced nuts and honey, sold at the Church-doors in Italy on Saints' days, are called comete"." Leonard Digges says that "comets signify corruptions of the ayre. They are signs of Earthquakes, of warres, of chaungyng of kingdomes, great dearth of corne, yea a common death of man and beast"." One John Gadbury says that "Experience is an eminent evidence, that a comet like a sword, portendeth war; and an hairy comet, or a comet with a beard, denoteth the death of kings." He also gives us a register of cometary announcements for upwards of 600 years, and adds in large Roman capitals, “as if God and nature intended by comets to ring the knells of princes, esteeming bells in Churches upon Earth not sacred enough for such illustrious and eminent performances." Shakespeare speaks of— "Comets importing change of times and states Milton says: "Satan stood Unterrified, and like a comet burned, That fires the length of Ophiuchus huge The last comet employed in an astrological character was that of 1769, which Napoleon I. looked upon as his protecting génie. Indeed, as late as 1808 Messier published a work on it, of which the title is given below. During the visibility of Donati's comet in 1858, the question was mooted whether the Bible contained any reference to these b Smyth, Cycle, vol. i. p. 231. A friend suggests a derivation which certainly appears much more rational; namely, comèdere, to eat. с Prognostication Euerlastinge, 2nd ed., London, 1576, fol. 6. d Henry VI., First Part, Act 1. Scene 1. • Paradise Lost, Book II. La Grande Comète qui a paru à la Naissance de Napoléon le Grand. objects: the following passages were adduced in support of the idea: 1. In Leviticus xvii. 7 it is said, "They shall no more offer their sacrifices unto Seirim," or Shoirim, which is rendered in the Authorised Version "devils," and in other versions "goats." Maimonides states that the Sabian astrologers worshipped these seirim, which seems to confirm the idea that they were celestial bodies. 2. In Isaiah xiv. 12 we find, “How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! For thou hast said in thy heart, I will ascend into heaven, I will exalt my throne above the stars of God." In this passage a certain Hillel is said to have fallen from heaven; but it is unknown what Hillel means. Some interpreters derive the word from Hebrew verbs signifying to glory, boast, agitate, howl, &c. Hillel may therefore signify a comet, for it answers to the ideas of brightness, swift motion, and calamity. 3. In the General Epistle of St. Jude, verse 13, certain impious impostors are compared to "wandering stars, to whom is reserved the blackness of darkness for an æon [age]." In all probability the passage may be taken to refer to comets 8. 4. The last quotation which I make is from the Revelation of St. John the Divine, xii. 3:-"There appeared another wonder in heaven; and behold a great red dragon, and his tail drew the third part of the stars of heaven." Satan is here likened to a comet, because a comet resembles a dragon (or serpent) in form, and its tail frequently does compass or take hold of the stars. These ideas are given for what they are worth, and that is probably not much. See Alford's New Test. for English Readers. In loco. CHAPTER VI. DETERMINATION OF THE ELEMENTS OF THE ORBIT OF A COMET BY A GRAPHICAL PROCESS a. THE SECTION 1. Preliminary. HE first and most important step to be taken in applying the following graphical process for the investigation of the orbit of a comet consists in working out the projection of the orbit on the ecliptic, which involves finding such an inclination of the plane of the orbit and such position of the node as shall be at once consistent with the longitudes and latitudes reduced from the observations available, and shall also satisfy Kepler's law of equal (or proportional) areas being described round the Sun in equal (or proportional) times; and afterwards to compare the developed orbit with one of the varieties of Conic Sections with which it must necessarily be in accord. This in practice means finding the proper parabola, for leaving out of consideration a few well-known elliptical comets of comparatively short period, the curve, whether elliptical or hyperbolic, approximates almost always so closely to the parabola that, until observations have been multiplied and all corrections for parallax and aberration have been applied, it is useless to attempt to discriminate between them. Moreover, the graphical method is scarcely available to indicate the course of a comet from only a few days' observations. Let a scale, divided into 100 parts, be made, on card or stout This chapter has been specially written for this work by Mr. F. C. Penrose, F.R.A.S., and is an extension of a paper contributed by him to the Royal Astronomical Society in 1881. (Month. Not., vol. xlvi. p. 68. Dec. 1881.) |