SEYFFARTH— ON THE THEORY OF THE MOONS MOTIONS. 4OI 



Corrections of the present Theory of the Moon's Motions, 

 according to the Classic Ecli-pses . 



Bv Prof. G. Seyffarth. A.M.. Phil. & Theol. D. 



Multiform! Luna ambage torsit ingenia contemplantium et, proximum ignorari sidus, 

 dignantium.— Pliny, II. N. ii 6, 12. 



INTRODUCTION. 



The present disquisitions were, four years ago, called forth 03' the learned 

 treatise, " Historical Eclipses," reprinted in Nature, New York, July 25, 

 1S72, to which my attention was directed by Dr. C. H. F. Peters, Director 

 of Litchfield Observatory, Hamilton College, Clinton, N. Y. The meritori- 

 ous author of the treatise, J. R. Hind, Director of Bishop's Observatory, 

 Twickenham, Eng., made the historical chronology of the Romans, Greeks, 

 and Babylonians, as set down in Petavius's Doctrina Temporum, and bona 

 fide repeated down to Clinton in all later chronologies, the groundwork of 

 his computations of ancient eclipses ; and, moreover, he presumed Hansen's 

 Lunar Tables, principally based on Ptolemy's Almagest, to be perfectly 

 correct. To both very much divulged prejudices I remonstrated in an 

 extensive letter of Feb. 11, 1873, which, soon after, was transmitted to Prof. 

 Hind. Compliance with the added request to publish my communications 

 in an astronomical journal seems to have been prevented by circumstances 

 down to this day. In the mean time many friends of history, even distin- 

 guished astronomers, being occupied with re-examining the usual theory 

 of the moon, desired, for the promotion of science, the publication of my 

 disquisitions concerning the true dates of ancient eclipses and the resulting 

 amendments of our Lunar Tables. These particulars, apart from others, 

 may excuse the final appearance of these historico-astronomical investi- 

 gations. 



In the next place the reader has to bear in mind that all, both historical 

 and astronomical dates, to be mentioned hereafter, refer to the astrono- 

 mical method of counting the years, and not to the so called historical 

 one, because the former is the most practical and the only true one. The 

 historians commence, in consequence of Beda Venerabilis, the original 

 Dionysian Era too late by one year, and augment all dates preceding the 

 Christian Era by a unit ; and hence they refer Christ's birth to a wrong 

 year. The astronomical year 400 B.C. is. according to the historians, the 

 401st B.C., and so forth. 



It is an axiom that no theory of the moon's motions can be correct, as 

 long as it does not correspond with the times and magnitudes of the most 

 reliably ascertained eclipses of old. The most trustworthy ancient eclipses, 

 however, are those mentioned in the classical works of the Romans and 

 Greeks; for, their authors were, in nearly all instances, eye-witnesses, 

 iii — 26 [May 20, 1S77.] 



