The Story of Eclipses

by George F. Chambers

ECLIPSES OF THE SUN MENTIONED IN HISTORY—CLASSICAL.

In this chapter we shall, for the most part, be on firmer ground than hitherto, because several of the most eminent Greek and Latin historians have left on record full and circumstantial accounts of eclipses which have come under their notice, and which have been more or less completely verified by the computations and researches of astronomers in modern times. But these remarks do not, however, quite apply to the first eclipse which will be mentioned.

Plutarch, in his Life of Romulus, refers to some remarkable incident connected, in point of time at any rate, with his death:—“The air on that occasion was suddenly convulsed and altered in a wonderful manner, for the light of the Sun failed, and they were involved in an astonishing darkness, attended on every side with dreadful thunderings and tempestuous winds.” This so-called darkness is considered to have been the same as that mentioned by Cicero.[36] There is so much myth about Romulus that it is not safe to write in confident language. Nevertheless it is a fact, according to Johnson, that there was a very large eclipse of the Sun visible at Rome in the afternoon of May 26, 715 B.C., and 715 B.C. is supposed to have been the year, or about the year, of the death of Romulus. Plutarch is also responsible for the statement that a great eclipse of the Sun took place sometime before the birth of Romulus; and if there is anything in this statement Johnson thinks that the annular eclipse of November 28, 771 B.C., might meet the circumstances of the case, but too much romance attaches to the history of Romulus for anyone to write with assurance respecting the circumstances of his career. Much of it is generally considered to be fabulous.

In one of the extant fragments of the Greek poet Archilochus (said to be the first who introduced iambics into his verses), the following sentence occurs:—“Zeus the father of the Olympic Gods turned mid-day into night hiding the light of the dazzling sun; an overwhelming dread fell upon men.” The poet’s language may evidently apply to a total eclipse of the Sun; and investigations by Oppolzer and Millosevich make it probable that the reference is to the total eclipse of the Sun which happened on April 6, 648 B.C. This was total at about 10 a.m. at Thasos and in the northern part of the Ægean Sea. The acceptance of this date displaces by about half a century the date commonly assigned for the poet’s career, but this is not thought to be of much account having regard to the hazy character of Grecian chronology before the Persian wars.[37]

On May 28, 585 B.C. there occurred an eclipse the surrounding circumstances of which present several features of particular interest. One of the most celebrated of the astronomers of antiquity was Thales of Miletus, and his astronomical labours were said to have included a prediction of this eclipse, which moreover has the further interest to us that it has assisted chronologists and historians in fixing the precise date of an important event in ancient history. Herodotus[38] describing a war which had been going on for some years between the Lydians and the Medes gives the following account of the circumstances which led to its premature termination:—“As the balance had not inclined in favour of either nation, another engagement took place in the sixth year of the war, in the course of which, just as the battle was growing warm, day was suddenly turned into night. This event had been foretold to the Ionians by Thales of Miletus, who predicted for it the very year in which it actually took place. When the Lydians and Medes observed the change they ceased fighting, and were alike anxious to conclude peace.” Peace was accordingly agreed upon and cemented by a twofold marriage. “For (says the historian) without some strong bond, there is little security to be found in men’s covenants.” The exact date of this eclipse was long a matter of discussion, and eclipses which occurred in 610 B.C. and 593 B.C. were each thought at one time or another to have been the one referred to. The question was finally settled by the late Sir G. B. Airy, after an exhaustive inquiry, in favour of the eclipse of 585 B.C. This date has the further advantage of harmonising certain statements made by Cicero and Pliny as to its having happened in the 4th year of the 48th Olympiad.

Another word or two may be interesting as regards the share which Thales is supposed to have had in predicting this eclipse, the more so, that very high authorities in the domains of astronomy, and chronology, and antiquities take opposite sides in the matter. Sir G. C. Lewis, Bart., M.P., may be cited first as one of the unbelievers. He says[39] that Thales is “reported to have predicted it to the Ionians. If he had predicted it to the Lydians, in whose country the eclipse was to be total, his conduct would be intelligible, but it seems strange that he should have predicted it to the Ionians who had no direct interest in the event.” Bosanquet replies to this by pointing out that Miletus, in Ionia, was the birthplace of Thales, and also that a shadow, covering two degrees of latitude, passing through Ionia, would also necessarily cover Lydia.

Another dissentient is Sir H. C. Rawlinson,[40] who, remembering that Thales is said to have predicted a good olive crop, and Anaxagoras the fall of an aërolite, says:—“The prediction of this eclipse by Thales may fairly be classed with the prediction of a good olive crop, or the fall of an aërolite. Thales, indeed, could only have obtained the requisite knowledge for predicting eclipses from the Chaldeans; and that the science of these astronomers, although sufficient for the investigation of lunar eclipses, did not enable them to calculate solar eclipses—dependent as such a calculation is, not only on the determination of the period of recurrence, but on the true projection also of the track of the Sun’s shadow along a particular line over the surface of the earth—may be inferred from our finding that in the astronomical canon of Ptolemy, which was compiled from the Chaldean registers, the observations of the Moon’s eclipse are alone entered.”

Airy[41] replied to these observations as follows:—“I think it not at all improbable that the eclipse was so predicted, and there is one easy way, and only one of predicting it—namely, by the Saros, or period of 18 years, 10 days, 8 hours nearly. By use of this period an evening eclipse may be predicted from a morning eclipse but a morning eclipse can rarely be predicted from an evening eclipse (as the interval of eight hours after an evening eclipse will generally throw the eclipse at the end of the Saros into the hours of night). The evening eclipse, therefore, of B.C. 585, May 28, which I adopt as being most certainly the eclipse of Thales, might be predicted from the morning eclipse of B.C. 603, May 17.... No other of the eclipses discussed by Baily and Oltmanns present the same facility for prediction.”

Xenophon[42] mentions an eclipse as having led to the capture by the Persians of the Median city Larissa. In the retreat of the Greeks on the eastern side of the Tigris, they crossed the river Zapetes and also a ravine, and then reached the Tigris. According to Xenophon, they found at this place a large deserted city formerly inhabited by the Medes. Its wall was 25 feet thick and 100 feet high; its circumference 2 parasangs [= 7½ miles]. It was built of burnt brick on an under structure of stone 20 feet in height. Xenophon then proceeds to say that “when the Persians obtained the Empire from the Medes, the King of the Persians besieged the city but was unable by any means to take it till a cloud having covered the Sun and caused it to disappear completely, the inhabitants withdrew in alarm, and thus the city was captured. Close to this city was a pyramid of stone, one plethrum in breadth, two plethra in height.... Thence the Greeks proceeded six parasangs to a great deserted castle by a city called Mespila formerly inhabited by the Medes; the substructure of its wall was of squared stone abounding in shells ... the King of the Persians besieged it but could not take it; Zeus terrified the inhabitants with thunderbolts, and so the city was taken.”

The minute description here given by Xenophon enabled Sir A. H. Layard, Captain Felix Jones, and others, to identify Larissa with the modern Nimrud and Mespila with Mosul. A suspicion is thrown out in some editions of the Anabasis that the language cited might refer to an eclipse of the Sun. It is to be noted, however, that it is not included by Ricciolus in the list of eclipses mentioned in ancient writers which he gives in his Almagestum Novum. Sir G. B. Airy, having had his attention called to the matter, examined roughly all the eclipses which occurred during a period of 40 years, covering the supposed date implied by Xenophon. Having selected two, he computed them accurately but found them inapplicable. He then tried another (May 19, 557 B.C.) which he had previously passed over because he doubted its totality, and he had the great satisfaction of finding that the eclipse, though giving a small shadow, had been total, and that it had passed so near to Nimrud that there could be no doubt of its being the eclipse sought.