the second day would belong to the Sun. Proceeding in the same way, the first hour of the third day would belong to the Moon, of the fourth to Mars, &c. We have said, that in the ancient systems, Venus and Mercury were considered as inferior to the Sun; but upon this point there was some difference of opinion. The Egyptians seem to have perceived the real state of the case. They conceived these two planets to move round the sun, while they followed him in his annual revolution round the earth, and consequently were sometimes nearer than he to the earth, sometimes farther. This system, which is explained by several ancient authors, and among them obscurely by Cicero, more distinctly by Vitruvius, is positively attributed to the Egyptians by Macrobius. Some have been disposed to imagine that the constellations of the zodiac were originally invented in Egypt at a very remote period. This opinion has been advocated principally by Dupuis §, who conceives that the constellations in question had a reference to the divisions of the seasons, and to the agriculture of Egypt at the time of their invention. The sign of Cancer marks the retrogradation of the sun at the solstice; Libra, the equality of the nights and days at the equinox: the Capricorn, a climbing animal, is conceived to indicate the sun at its greatest height, or at the summer solstice; the autumnal equinox consequently falls in Aries. This system presents, certainly, some curious coincidences: thus, for example, the inundation of the Nile, which begins just after the summer solstice, would take place while the sun was in the constellations Aquarius and Pisces; and Virgo, usually represented as a woman with an ear of corn in her hand, would coincide with the time of harvest in Egypt. There is, however, one insuperable objection to this system, which is the excessive antiquity (not less than 15000 years) which it assigns to the zodiac. As this is historically inadmissible, Dupuis has modified his theory by supposing the names to have been given, not to the constellations in which the sun was, but to those diametrically opposed to him, which consequently were rising at sun-set at any given epoch. This opinion, which brings down the invention of these constellations to about 2500 years B.C., has been adopted by • Somn. Scip. + Vitruv., lib. ix. c. 4. La Place and several distinguished philosophers *. The scientific men who accompanied the French expedition to Egypt found in some of the temples of that country representations of the zodiac, which have given rise to much discussion in Europe. One of the most remarkable of these is on the ceiling of a portico in the temple of Denderah (the ancient Tentyra). It represents the signs of the zodiac in two rows, six in each, parallel to the axis of the temple, one to the right, the other to the left of the principal entrance; the latter all face, as if about to enter the temple, the former as if quitting it: the first of the entering signs is Aquarius, and the last Cancer: the Cancer, however, is thrown on one side out of the line, and its place filled by a head of Isis, partly plunged in the rays of the sun. It follows, from what has been said, that the first of the signs which appear to be coming out is the Lion, and the last Capricorn. Similar zodiacs are to be found in the porticoes of two temples at Esnè (Latopolis): but there the head of Isis is altogether wanting, and the bisection of the signs takes place between Virgo and Leo, instead of between Leo and Cancer. This bisection has been supposed by some to have a reference to the places of the solstices: but the supposition is entirely arbitrary, and would give to these temples an antiquity) which other circumstances by no means seem to support. Fourrier conjectures that the head of Isis, substituted in the place of Cancer, indicates that Sirius rose heliacally when the sun was in that constellation; which took place more than twenty centuries before the Christian era. M. Biot imagines that this indicates that Sirius rose with the stars of Cancer, near which the sun was at the time of the summer solstice, and refers the monument to about the year 700 B.C. There is in the interior of the temple at Denderah, another zodiac, sculptured on a ceiling, in which the signs are arranged in a circle, and here * Macrobius (Somn. Scip., lib. i. c. 21.) attri butes the invention of the zodiac to the Egyptians; but against this it may be urged, that Sextus Empiricus, a writer of at least equal authority, ascribes it to the Chaldeans, lib. v. This idea is deduced from the supposition that the constellation in which the sun was at the beginning of the year, was represented as the first in the line of the signs coming out of the temple, or appearing to lead the others: now the Egyp tian rural year began at the summer solstice-thus the zodiac of Denderah would indicate that the summer solstice was in the Lion, those of Esnè in the Virgin. again the Cancer is thrown out of its proper line, its place being occupied by a mythological figure, below which is the symbol of Isis. M. Biot has attempted to prove that this circular zodiac is a planisphere representing the appearance of the heavens at midnight on the summer solstice, about seven centuries before the Christian era. But this opinion is exposed to many serious objections: these, however, the limits of this treatise will not allow us to enter into: we shall quit the subject with one observation. M. Champollion thinks he has decyphered among the hieroglyphics on the ceiling of the temple, the word abrogare, which would seem to indicate that the sculptures in question were as recent as the Roman empire. But this by no means precludes the possibility that they may represent a more ancient sphere. That the temple itself is not of great antiquity many circumstances seem to indicate; but the question to be solved is, whether the astronomical phenomena it depicts are, or are not, to be referred to some more distant epoch, which it was intended to record? CHAPTER V. Origin of Astronomy in Greece. Thales. The Ionian School. The Pythagoreans.-Meton-The Calendar.-Eudoxus.-Pytheas. THE astronomy of Greece undoubtedly begins with Thales and the philosophers of the Ionian School, about six centuries before the Christian era. Homer, indeed, and Hesiod, the only authors anterior to this period whose works we now possess, mention some of the most remarkable constellations, though none of those composing the signs of the zodiac;t and the works of the latter author in particular show that some attention was paid in his time to the rising and setting of certain conspicuous stars. Thus he informs us that Arcturus rose heliacally sixty days after the winter solstice, from which we may deduce this poet to have lived about 950 B.C., unless, Recherches sur l'Astronomie Egyptienne. Paris, 1823. The constellations and stars mentioned by Homer, are the Bear, the Pleiades, the Hyades, Bootes, Orion, and Arcturus. Besides these Hesiod mentions Sirius. Neither make any mention of the planets, though Homer is supposed to allude to Venus in one passage-II. V. v.5; others think Sirius is meant. The planets in fact do not seem to have been astronomically observed in Greece till long afterwards. "Eudoxus," says Seneca, "quinque syderum cursus primus in Græciam ab Ægypto transtulit." Quæst. Nat. vii, 3, Op. et. Dies. v. 564. indeed, which is not improbable, he copied some older calendar.* Herodotus † makes Homer and Hesiod contemporaries, and places them about 400 years before his own time, which would make them a century later than the date above assigned. But the whole question of their age is involved in much doubt and obscurity, nor is it important to the history of astronomy. We find little in these very ancient authors that throws light upon the interesting question, whether the Greek sphere was derived from that of the Egyptians, or other oriental nations. We shall see in the course of this treatise, that there can be no doubt that the zodiac was borrowed from Egypt or Chaldea, but the origin of the extra-zodiacal constellations is very uncertain. Senecat attributes the division of the heavens into constellations to the Greeks; and refers this division to fourteen or fifteen centuries before Christ. An obscure author, quoted by Clemens Alexandrinus,§ ascribes the invention of the sphere to Chiron, who may be referred to the thirteenth century B.C. That the Greek sphere, whether of native or foreign origin, is as old as the time assigned to Chiron, has been attempted to be proved by a passage from Eudoxus, quoted in the commentary of Hipparchus on Aratus. This author, who flourished in the early part of the fourth century B.C. asserts, that there is a certain star in the celestial sphere, corresponding to the pole of the equator. Now this could not have been the polar star of our times, which was then, owing to the precession of the equinoxes, far from the pole; and upon examining that part of the heavens, there seems to be no other star that could be alluded to, except Draconis. About 1326 B.C. this star was within 4° of the pole, which was sufficiently near to make it appear immoveable to rude observers: and this fact has been thought to show that Eudoxus copied a sphere many centuries anterior to his own. This sphere has been supposed to be that of Chiron before alluded to; others attribute it to Musæus.¶ But not withstanding all that has been said upon this subject, it seems pretty evident, the positions of the stars given by Eudoxus are too discordant to admit of any conclusion being drawn from them*, and if Eudoxus copied any very ancient sphere, it must have been one of oriental origin; for in the time of Chiron (if indeed any such person ever existed) it is pretty certain that nothing was known in Greece about the existence of the ecliptic, the equinoxes, the colures, or any great circles of the sphere. The unanimous testimony of antiquity ascribes to Thales, or his immediate successors among the philosophers of the Ionian school, the invention of the zodiac, the discovery of the obliquity of the ecliptic, of the tropical revolution of the sun, and the principal circles of the celestial sphere. There is no reason for supposing that, before this time, the Greeks had advanced beyond remarking and naming a few of the most conspicuous constellations; and how little progress they had made in this, we may conjecture from the circumstance, that Thales first introduced into Greece the knowledge of the Little Bear+, by which the Phoenician pilots used to steer, while the Greeks were contented with the rough approximation to the north given by the Great Bear. For it is very remarkable that Thales, if not, as some have pretended, a Phoenician, was certainly of Phoenician extraction; and this fact, corroborated by other authors, rests on the testimony of Herodotus himself, Many things seem to indicate that the science of Thales was of eastern origin, and that what have been called his discoveries, were doctrines borrowed from Chaldæa or Egypt. Much stress is not to be laid upon the account of his having studied in Egypt, which rests upon the equivocal authority of his biographer Diogenes, though this is confirmed by Clemens Alexandrinus§. But the extraordinary fact of his having predicted a solar eclipse, which can scarcely be dis (V. Sophocles quoted by Achilles Tatius), and Atlas (V. Diod. Sic. lib. iii. Plin. ii. S.) V. Delambr. Astron. Anc. Introduct. p.11. and vol. i. p. 122. † See Callimachus quoted by Diogenes Laertius in Thalete, and by Achilles Tatius, Cf. Hygin. Poetic. Astronom. V. Arctus. et Theon. in Arat. That the Little Bear was discovered by the Phoenicians, is attested by Strabo (lib. i. cap. 1), and the circumstance of their navigators sailing by it, is alluded to by many authors. V. Arat. Phonom. y. 39. Ovid. Heroid. xviii., et alibi. V. Herodot., lib. i. c. 170, Cf. Diog. Laert, in Thalete. Stromat. i. 14, puted, speaks volumes upon this subject. This we are told by Herodotus*, whose testimony seems above all suspicion, though he adds a singular circumstance, in which there is probably some mistake, that Thales assigned the limits of a year, within which this eclipse was to take place. It is unnecessary to remark, that could Thales have predicted an eclipse so remarkable as this, which was total in the country in which he lived-Asia Minor, he certainly must have been able to make a much nearer approximation. But as to the fact of the prediction there can be little doubt. eclipse is memorable in ancient history, as having separated the armies of the Lydians and Medes, at that time engaged in battle; the historian lived not more than 150 years after the event in question, and was a countryman of Thales; but should his testimony be deemed insufficient, authority perhaps still higher may be quoted. Eudemus, The an astronomer of eminence in the fourth century before Christ, composed a history of astronomical discoveries, now unfortunately lost; but Diogenes Laertius and Clemens Alexandrinus both quote the authority of Eudemus for this prediction of Thales: and in farther cor roboration of this, Eudemus, in a fragment preserved by Anatolius§, attributes the discovery of solar eclipses to Thales. Indeed it may be said that there is no point on which the testimony of antiquity is more decided and unvarying, than that Thales introduced into Greece the prediction of solar eclipses ||, and most probably at the same time the explanation of their real cause. Pliny indeed does not quite agree with Eudemus as to the date of this eclipse, which has been a subject of controversy among ancient and modern authors; but the knowledge of the exact year in which it happened is more interesting to chronologists than astronomers**. • Lib. i.c. 74. †Thales was a native of Miletus-Herodotus of Halicarnassus, both towns on the coast of Asia Minor. V. Diog. Laert. in Thal. Clem. Alex. Stromat. lib. i. c. 14. V. Fabric. Bibliothec. Græc., lib. iii. c. ii. Vol. ii. p. 215. Hamburgh, 1797. Besides the authors above quoted, V. Achilles Tat. Isagog. Plin. Hist. Nat. ii. 12. Cicero de Divinatione i. This is expressly attributed to him by Plutarch de Placit. Philosoph. ii. 24. **On this point the reader is referred to aninteresting paper by Mr. Bailly, in the Philosophical Transactions for 1811, where all the opinions on the subject are discussed. Mr. Bailly himself refers the eclipse to the year 610 B.C. If, then, there be no reason to doubt that Thales predicted the phenomenon in question, we can hardly fail to admit that his method was borrowed; and borrowed, in all probability, from Chaldea. For it is sufficiently clear that nothing but a very long series of observations, conducted with care and regularity, could enable any man to arrive at this knowledge; such observations, as we have no reason for supposing to have been made in Greece at these early times; while, on the other hand, we have seen that the Chaldeans were in possession of a period which enabled them to predict pretty accurately the recurrence of eclipses. Again, if we admit that Thales explained the causes and predicted the occurrence of eclipses of the sun, we can hardly doubt that he was able to do the same with regard to those of the moon. Eudemus, indeed, according to Anatolius, attributes the discovery of the causes of the moon's light and her eclipses to Anaximenes, one of the successors of Thales. In general, we may remark, that it is very difficult to determine, amid conflicting testimony, to which of the philosophers of these times particular discoveries are to be referred, though there is a general agreement as to the doctrines taught in the Ionian and Pythagorean schools. Thus Pliny refers the discovery of the obliquity of the ecliptic to Anaximander,-Plutarch + to Pythagoras, or Enopides of Chios, Eudemus to some author whom he does not name, but different from all of these, and who fixed it at 24°. But Thales, who is said to have written on the length of the tropical year, and on the position of the solstices and equinoxes §, could hardly have been ignorant of the fact of the obliquity, even if he were not, as seems likely, the author of this ancient valuation. Again, the invention of the gnomon is attributed by Diogenes Laertius || to Anaximander,—and by Pliny to Anaximenes,-while Herodotus, with much more probability, says it was borrowed from the Babylonians **, It is ⚫ Pliny, ii. 8. II. c. 56. † De Placit. Phil. ii. 12. Fabric. Bibliothec. Græc. 1. c. Diog. Laert. in Thalete. I In vita Anaximandri. * See the passage quoted above, chap. lii. With regard to Thales, we may observe, that Themistius, in a passage quoted by Fabricius, Bibliothec. Græc. vol. i. p. 239, says, that Anaximander was the first person who published any of the doctrines of Thales, this latter having written nothing him. self. This would tend to confirm the view taken in the text, that the pretended discoveries of truly unfortunate, that in attempting to investigate the doctrines of these ancient philosophers, we are compelled to have recourse to authors whose ignorance of astronomy too often makes their accounts unintelligible. Thus Diogenes tells us, that Thales found the magnitude of the moon to beth part of the sun; a statement clearly absurd, if meant to apply, as it evidently must, to their apparent diameters. But a passage of Apuleius* shows us the real meaning of the determination so grossly misunderstood by Diogenes. Thales, he tells us, determined the magnitude of the sun in parts of its own orbit: now, th part of a great circle is 30': the real diameter of the sun may be taken at a mean not far from 32'; so that we see the measure of Thales was a good approximation for those early times.+ We have stated above, that the constellations of the zodiac do not seem to have been known in Greece before the time of Thales. In fact, Eudemus, whose early date and astronomical knowledge make his testimony of great weight, states that they were invented by Enopides of Chios, a Pythagorean philosopher, generally placed considerably after the time of Thales. However, that they were not of Greek origin, seems highly probable, let them have been introduced into that country when they may. To establish this, it is not necessary to insist upon the zodiacs discovered in Egypt, since their antiquity has been disputed; but from the testimony of ancient authors, it is clear that the zodiac of Chaldea and Egypt was identical with that of Greece; and no doubt can remain as to which was borrowed from the other. The Syntaxis of Ptolemy establishes this identity in the case of Chaldea and Greece. In the planetary observations of the Chaldeans, quoted in that work, the place of the planet in the Chaldean zodiac is first given, and then reduced to the Greek: though the respective constellations did not quite coincide in space, yet the names are always identical, except in one instance, where it appears that the Chaldeans gave the name of the Balance Anaximander and Anaximenes consisted in the publication of what they had learnt from Thales. • Florid. V. Montucla, vol. i. p. 106. Bailly, Astron. Anc. p.441. Pliny refers the invention to Cleostratus of Tenedos, a philosopher rather posterior to Thales, but before the time to which Enopides is usually referred. V. Hist. Nat. ii, 9, to the constellation called by the Greeks the claws of the Scorpion. From a fragment quoted by Delambre †, it seems that the Egyptians also named the claws of the Scorpion the Balance. To this we may add the very curious circumstance, that the zodiac of India is nearly identical with that of Greece: and Humboldt has shown, in a very interesting memoir, that the twelve Indian signs are taken from among the twentyseven lunar mansions, or constellations of the lunar zodiac, mentioned in the first and second chapters of this Treatise §. Nothing, perhaps, is more remarkable, and, if we refuse to admit the oriental origin of Greek science, more inexplicable, than the circumstance of the true doctrine of the motion of the earth having been promulgated in the schools of Pythagoras || and Thales. That this was the case with regard to the former, is well known; and it is generally supposed that Philolaus, the successor of Pythagoras, was the first to teach it openly T. But there are some reasons for supposing that it had been among the doctrines professed at an earlier period by Anaximander. Eudemus, whom we have frequently had occasion to quote, affirms, in the most express terms, that this was the system of Anaximander**. If this be true, it is as probable that this philosopher merely published what he had heard from his master, as (in the case of Philolaus and Pythagoras ++. Cicero, on the authority of Theophrastus, attributes this system to Hicetas of Syracuse; and this is partly confirmed by Plutarch §§. It certainly was embraced by some very eminent men, such as The statements of Macrobius and Sextus Em pericus, on the zodiac, have been mentioned above They are in complete accordance with what is here advanced. This appears from Aristot. de Cœlo, 1. ii. c. 13, and Plutarch in Numa, c. ii. V. Plutarch de Placit. Philos. lib. iii. cc. 13 and 17; Diog. Laert. in Philolao. Philolaus flourished about 450 B.C. **Fabric. Bibliothec. Græc. 1. c. Delambre grossly mistranslates this passage. Astron. Anc., vol. i. p. 15. It is but fair to state, that Simplicius places Anaximander among those who conceived the earth to be in the centre of the universe. De Cœlo, lib. ii. + Plutarch de Placit. Phil. iii. 11, certainly informs us that Thales placed the earth in the centre e universe; his testimony, however, cannot clusive, when unsupported by any other. est. Academ, iv. 39. Placit, Phil, iji. 13, Archytas of Tarentum, Timæus Locrus, and, in later times, Aristarchus of Samos*. Others, as Heraclides of Pontus, and Ecphantus, admitted, we are told, merely the earth's diurnal revolution on its axis. One cannot help feeling some surprise, that after the true system of the world had once been promulgated,-when it had been adopted by a numerous school, and some of the most distinguished astronomers, it should have fallen subsequently into comparative oblivion. No doubt the ancients had not the same decisive proof of the motion of the earth that we have in the aberration of the fixed stars; and the infinite distance of these bodies, which is a necessary consequence, may have staggered many of them. But the fact in question is principally to be attributed to the widespreading influence of the Peripatetic school, whose founder, Aristotle, had strenuously combated the Pythagorean doctrines . It is a circumstance by no means to be overlooked, that Pythagoras had travelled, according to the testimony of all his biographers, into Egypt and the East, and some say that he penetrated as far as India §. Some corroboration of this circumstance might be found in his metaphysical doctrines, evidently borrowed either from India or Egypt; but to confine ourselves merely to astronomy, we may notice opinions analogous to those known to have existed in the countries we have mentioned. We have seen the belief of the Chaldeans about comets, according to the account of Apollonius Myndius: the Pythagorean doctrine on this subject bears the greatest analogy to it. These philosophers supposed comets to be bodies as ancient as the universe, revolving round the their orbit. Yet this sublime concepsun, and visible only in a certain part of tion shared the fate of the system of the earth's motion. The Peripatetics were once more triumphant over truth and reason; and for eighteen centuries, it was almost universally admitted that these bodies were simply meteors engendered in the terrestrial atmosphere. The philosophical ideas of the Pytha * Archimedes in Arenario.-Plutarch de Placit. Phil. ii. 24. Plato is said by Plutarch to have regretted, in his old age, having placed the earth in the centre of the universe.-Qnæst. Plat. + Plutarch de Placit. Phil. iii. 13. De Cœlo, lib. ii. Iamblichus, Diogenes, Apuleius in Floridis, |