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undoubtedly must be a very sorry one. I cannot apprehend that Thales could settle the equinoxes with so much exactness, as that any great stress Could have been laid even upon his account of the Pleiades setting twenty-five days after the autumnal equinox. He might, or might not happen to err a day or two about the time of the equinox: and as much about the setting of the Pleiades,

Sir Isaac Newton observes, that Meton, in order to publish his lunar cycle of nineteen years, observed the summer solstice in the year of Nabonassar 316, and Columella (he says) placed it in the eighth degree of Cancer. From whence he argues, that the solstice had gone back from Chiron's days to Meton's at least seven degrees, and therefore Meton was but five hundred and four years after Chiron." But here again the argument depends upon Chiron's having accurately settled the equinoxes in his time;

* Chronology of the Greeks, p 93.

therefore the answer I have before given will here be sufficient. As to Meton, from this account of his settling the equinoxes, and from Dean Prideaux's of his nineteen years cycle," it would seem probable that he was a very exact astronomer. But I must confess, there appear to me to be considerable reasons against admitting this opinion of him; for how could Meton be so exact an astronomer, when Hipparchus, who lived almost three hundred years after Meton," was the first who found out that the equinox had a motion backwards, since even he was so far from being accurate, that he miscounted twenty-eight years in one hundred, in calculating that motion ?p Meton might not be so exact an astronomer as he is represented. The cycle which goes under his name might be first projected by him; but perhaps he did not give it that perfection which it afterwards received. Columella lived in the time

• Prideaux Connect. vol. ii. p. 6.

• Newton's Chronology, p. 94. * Id. Ibid.

of the emperor Claudius, and he might easily ascribe more toMcton than belonged to him, as living so many ages after him. Later authors perfected Melon's rude draughts of astronomy; and Columella might suppose the corrections made in his originals by later hands to be Meton's. We now call the nineteen years cycle by his name; but I sup* pose that nothing more of it belongs to him, than an original design of something like it, which the astronomers of after-ages added to and completed by degrees.

Before I dismiss the astronomical argu* ment of our truly great author, I would add the very celebrated Dr. Halley's account of the astronomy of the ancients; which he communicated some years ago to the author of " Reflections upon Ancient and Modern Learning." His words are,t

The astronomy of the ancients is usually reckoned for one of those sciences, wherein the learning of the Egyptians consisted; and

'Sec Wotton's Reflections upon Ancient and Modem Learning, chap. 84, p. 380. .

and Strabo expressly declares, that there were several universities in Babylon, wherein astronomy was chiefly professed; and Pliny tells us much the same thing. So that it might well be expected, that where such a science was so much studied, it ought to have been proportionably cultivated. Not* withstanding all which it does appear, that there was nothing done by the Chaldeans older than about four hundred years before Alexander's conquest, which could be serviceable either to Hipparchus pr Ptolomy in their determination of the celestial motions: for had there been any observations older than those we have, it cannot be doubted but the victorious Greeks must have pro* cured them, as well as those they did, they being still more valuable for their antiquity. All we have of them is only seven eclipses of the moon preserved in Ptolomy's Syntaxes; and even those are very coarsely set down, and the pldest not much above seven hundred years before Christ; so that after all the fame of these Chaldeans, we may be pure that they had not gone far in this

PREFACE. XX1H

science. And though Callisthenes is said by Porphyry to have brought from Babylon to Greece observations above one thousand nine hundred years older than Alexander; yet the proper authors making no mention or use of any such, renders it justly suspected for a fable.' What the Egyptians did in this matter is less evident; because no one observation made by them can be found in their countryman Ptolomy, except what was done by the Greeks of Alexandria under three hundred years before Christ. Therefore whatever was the learning of these two ancient nations, respecting the motions of the stars, it seems to have been chiefly theoretical; and I will not deny, but some of them might very long since be apprized of the sun's being the centre of our system, for such was the doctrine of Pythagoras and Philolaus, and some others, who were said to have travelled into these parts.

'Callisthenes' account may not be a fable: the subsequent authors neither mentioned nor used these observations, because they were in truth, such sorry ones, {hat no use could be made of them.

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