(2) That the elements either of the Moon's motion or of the Sun's need a drastic change so as to bring the zone of annular eclipse close to Athens. The magnitude, if annular, would be 11·88 or 99100 of totality. This was Dr. Cavell's solution,[1] but the elements which he adopts fail to satisfy the critical eclipse of Hipparchus.
(3) That the place of observation was at a distance from Athens. The Rector of Lincoln has ingeniously argued[2] that Thucydides may have been on an embassy to the Thracian king and have watched the eclipse from the neighbourhood of Adrianople.
Now all these suggestions are rendered unnecessary by the results established by last month's eclipse. That eclipse attained a magnitude of 10·7 digits at Oxford; that means that eight-ninths of the Sun's diameter were eclipsed. That is, one-fifth of a digit more than at Athens in B.C. 431. In neither case was the Sun high above the horizon. At Oxford last month the eclipse attained its greatest phase at 9·47 a.m. summer time, that is, at 8.40 a.m. local solar time, while at Athens in B.C. 431 the greatest phase according to my computation was at 5.31 p.m. local solar time, ours being a morning eclipse, theirs an evening eclipse. I find that the Sun's altitude here was 29° above the horizon, the Sun's altitude there was 17°. The sky was remarkably clear here, with occasional thin clouds. The sky is nearly always clear at Athens. At our eclipse the brightest stars in the sky were Venus and Vega. At Thucydides' eclipse the brightest stars in the sky were Venus and Vega. Probably the Athenian eclipse would be the better for seeing stars, the difference of 12° in the Sun's altitude being more important than the difference of a fifth of a digit in the
