This must of necessity be a brief chapter, so far as mere lines of text are concerned, but it will not on that account be unimportant. It will be evident to the reader that many more eclipses of interest have happened, and will happen, than it has been possible to speak of in these pages. Accordingly, as it is one of the main objects of this series of volumes to create a thirst for knowledge, to be satisfied by the study of other and bigger volumes, it will be desirable to furnish a list of some of the various books and publications, in which eclipses will be found catalogued or described in detail, so that readers desirous of pursuing the matter further, may possess facilities for doing so.
By far the most complete and comprehensive catalogue of solar eclipses is that prepared some years ago by an Austrian astronomer, the late Theodore Von Oppolzer of Vienna, and published under the title of Canon der Finsternisse, in the Memoirs of the Imperial Academy of Sciences.[144] This work supplies approximate calculations of about 8000 eclipses of the Sun, for a period of more than 3000 years, from November 10, 1207 B.C. (Julian Calendar), to November 17, 2161 A.D. (Gregorian Calendar). There are appended 160 charts, of all the principal eclipses; but as the charts only exhibit the beginnings, middles, and ends of the eclipses dealt with, they are frequently misleading, because the intermediate lines of path are, in many cases, more or less considerably curved.
Another very important and comprehensive catalogue of eclipses, solar and lunar together, will be found in the well-known French work, L’Art de vÉrifier les Dates,[145] compiled by a member of the religious order of St. Maur. One volume of this famous work contains eclipses from the year 1001 B.C. to the Christian Era, whilst another volume gives a similar catalogue from the year 1 A.D. to 2000 A.D. The other volumes deal with chronological matters only. Although not strictly a work of extreme astronomical exactness, yet L’Art de vÉrifier les Dates stands unrivalled as a record not only to subserve the purpose indicated by its title, but of the bare facts of the eclipses which have happened during the period of 3000 years stated above.
There has not been much done in England in the way of publishing eclipse records or tables, past or future, but in the British Almanac and Companion for 1832 there is given a catalogue, which was useful in its day, of eclipses, then future from 1832 to 1900, omitting, however, solar eclipses hardly visible to any inhabited portion of the Earth, and lunar eclipses where the part of the Moon’s diameter obscured was less than 1/12th.
In by-gone days several attempts were made to gather together in a tabular or paragraph form the details of eclipses which had happened, and some of these have been important sources of information for the guidance of us moderns. Foremost amongst these efforts must be named the Almagestum Novum of J.B. Ricciolus.[146] This work contains a catalogue of eclipses observed from 772 B.C. to A.D. 1647, and continued in tables to A.D. 1700. It is prefaced (pp. 286-8) by a long series of quotations from classical authors relating to eclipses, some few of which have already been mentioned in these pages.
Kepler paid much attention to eclipses, and left behind him a large mass of notes and original observations. These will be found chiefly in his AstronomiÆ Pars Optica, c. vii. §2, originally published at Frankfurt in 1604. The most convenient and accessible edition of this is to be found in Frisch’s reprint of all Kepler’s works.[147]
Tycho Brahe also gathered together from various sources many observations of eclipses, and combined them with a number of his own, the whole being published in his Historia Coelestis.[148] Tycho Brahe was a very interesting personage in spite of the fact that he went all astray on the subject of the system of the Universe, and he well deserves, what has been given to him, a book[149] all to himself. It is peculiarly appropriate that I should give him a good word in this little volume on eclipses, because it was the solar eclipse of Aug. 21, 1560, which first seriously led him to take up astronomical pursuits, he being then 14 years of age, and struck with wonder that eclipses could be predicted.
A vast amount of historical and other information respecting eclipses will be found in a book, the latinised name of whose author is Sethus Calvisius. The title of the work is Opus Chronologicum.[150] The historical matter is very much mixed, but the eclipses can be got hold of through the Index, which is very full. P. Gassendi,[151] a well-known astronomer of the 17th century, left behind him observations of many eclipses observed by himself between 1628 and 1655. In a book entitled An Introduction to Universal Geography,[152] one Nicolas Struyck in the middle of the 18th century published a very full array of eclipse observations collected with infinite pains from an endless variety of authors ancient and modern.
In 1757 the well-known James Ferguson reprinted in his Astronomy,[153] but in a very condensed form, all Struyck’s eclipses from 721 B.C. to A.D. 1485. Then he carried on his catalogue to 1800 by means of the materials furnished by Ricciolus and L’Art de vÉrifier les Dates. Ferguson also invented a machine for illustrating mechanically the circumstances of an eclipse. He called it the “Eclipsareon.” A full description is given in his book, mentioned above, but I do not know whether any such instrument is still in existence, or, if so, where it is to be found.
Ferguson apologises[154] for the incompleteness of his eclipse information in the following words:—“I have not cited one half of Ricciolus’s list of portentous eclipses, and for the same reason that he declines giving any more of them than what that list contains, namely, that ‘tis most disagreeable to dwell any longer on such nonsense, and as much as possible to avoid tiring the reader. The superstition of the ancients may be seen by the few here copied. My author further says that there were treatises written to show against what regions the malevolent effects of any particular eclipse was aimed, and the writers affirmed that the effects of an eclipse of the Sun continued as many years as the eclipse lasted hours, and that of the Moon as many months.”
The most comprehensive (indeed almost the only) modern English book on eclipses is the Rev. S.J. Johnson’s,[155] of which frequent use has already been made in these pages. It contains a vast amount of matter put together in a condensed form but the references to authorities are rather defective and deficient. Less comprehensive in one sense yet exceedingly valuable and interesting as a succinct summary of solar eclipse knowledge up to the date of 1896 is Mrs. D.P. Todd’s excellent little volume[156] which has been several times quoted on previous pages. On various occasions in 1890 and following years Professor J.N. Stockwell contributed to the American Astronomical Journal a number of papers[157] discussing in a very interesting and exhaustive manner many of the eclipses recorded by the ancient classical authors. These papers should be consulted by all who desire to realise the value of eclipse records in connection with mundane chronology.
The calculation of eclipses is a matter of some interest. It is beyond the scope of the present work to explain even in outline the methods in use, but with the aid of the books mentioned below[158] a reader possessed of the necessary time, mathematical knowledge, and patience, will be able to pursue this matter as far as his inclination may lead him. Johnson has found very useful the tables given in the eighth edition of the EncyclopÆdia Britannica (Article, “Astronomy”) but strange to say these tables do not appear in ninth edition of that famous work.
Lalande[159] has given numerous references to eclipses of the Sun during the 16th, 17th and 18th centuries which may be useful to those who wish to work at the history of eclipses.
