AUTHORITIES.--The richest mine of information respecting eclipses of the sun and moon is T.R. von Oppolzer's "Kanon der Finsternisse," published by the Vienna Academy of Sciences in the 52nd volume of its _Denkschriften_ (Vienna, 1887). It contains elements of all eclipses both of the sun and moon, from 1207 B.C. to A.D. 2161, a period of more than thirty centuries. Appended to the tables is a series of charts showing the paths of all central eclipses visible in the northern hemisphere during the period covered by the table. The points of the path at which the eclipse occurs, at sunrise, noon and sunset, are laid down with precision, but the intermediate points are frequently in error by several hundred miles, as they were not calculated, but projected simply by drawing a circle through the three points just mentioned. For this reason we cannot infer from them that an eclipse was total at any given place. The correct path can, however, be readily computed from the tables given in the work. Eduard Mahler's memoir, "Die centralen Sonnenfinsternisse des 20. Jahrhunderts" (_Denkschriften_, Vienna Academy, vol. xlix.), gives more exact paths of the central eclipses of the 20th century, but no maps. General tables for computing eclipses are Oppolzer's "Syzygientafeln für den Mond" (Publications of the _Astronomische Gesellschaft_, xvi.), and Newcomb's, in _Publications of the American Ephemeris_, vol. i. part i. Of these, Oppolzer's are constructed with greater numerical accuracy and detail, while Newcomb's are founded on more recent astronomical data, and are preferable for computing ancient eclipses. F.K. Ginzel's _Spezieller Kanon der Sonnen- und Mondfinsternisse_ (Berlin, 1899) contains, besides the historical researches already mentioned, maps of the paths of central eclipses visible in the lands of classical antiquity from 900 B.C. to A.D. 500, but computed with imperfect astronomical data. Maguire, "Monthly Notices," _R.A.S._ xlv. and xlvi., has mapped the total solar eclipses visible in the British Islands from 878 to 1724. General papers of interest on the same subject have been published by Rev. S.J. Johnson. A résumé of all the observations on the physical phenomena of total solar eclipses up to 1878, by A.C. Ranyard, is to be found in _Memoirs of the Royal Astronomical Society_, vol. xli. A very copious development of the computation of eclipses by Bessel's method is found in W. Chauvenet's _Spherical and Practical Astronomy_, vol. i. _The Theory of Eclipses_, by R. Buchanan (Philadelphia, 1904), treats the subject yet more fully. Hansen's method is developed in the _Abhandlungen_ of the Leipzig Academy of Sciences, vol. vi. (Math.-Phys. Classe, vol. iv.). The formulae of computation by this method are found in the introductions to Oppolzer's two works cited above. (S. N.)