OF AGATHOCLES, THALES, AND XERXES. 
181 
(equivalent to Burg’s), exhibits the detailed elements of several eclipses, and finds 
that the eclipse of b.c. 610 , September 30 , was total on the Halys and atErzeroum (a 
result agreeing precisely with Mr. Baily’s), and, like Mr. Baily, he adopts that as 
the true eclipse of Thales. He then subjoins a very valuable table, exhibiting 
roughly the track of the central shadow in every eclipse, whether total or not (113 in 
number), as computed by means of the same tables, from b.c. 631 to 585 . 
6. The successive alterations in the adopted motions of the moon’s node have been 
nearly as follows. I must premise that there is much confusion among the original 
writers, from the circumstance that some in speaking of secular motions refer that 
term to a Julian century, while others use an ordinary Gregorian century, which 
differs from the Julian by one day, and produces a difference of 3' 16"‘4 in the motion 
of the node. I have endeavoured to remove this obscurity by giving the motion in 
all cases for a Julian century. 
Lalande, in the third edition of his Tables, 1792, had made the secular 
regression of the moon’s node 134 11 15 
Laplace, in the Additions to the Connaissance des Temps, An. VIII., 
from Albatenius’ discussion of Ptolemy, found that the motion 
was to be diminished to 134 8 25 
Burg and Oltmanns, 1806 and 1808 , adopted 134 11 42 
Bouvard, Monatliche Correspondenz, 1811 , May, found from the 
discussion of numerous eclipses 134 9 42 
Burckhardt’s Tables, 1812 , adopt 134 10 12 
Oltmanns, Berliner Jahrbuch, 181 / (printed about three years earlier), 
found from eclipses in 1239 and 1241 I34 10 28 
Murm, Zeitschrift fiir Astronornie, I817, January and February, found 
from twelve ancient lunar eclipses I34 g 23‘8 
and from eight total or annular solar eclipses . 134 g 25*6 
Damoiseau’s Tables, 1824 , adopt 9 57-5 
7. In the Berliner Jahrbuch, 1824, is a paper by Oltmanns, dated 1821, May 15, in 
which for the first time Mr. Baily’s researches are mentioned. M. Oltmanns remarks 
that the close agreement between Mr. Baily’s results and his own on the eclipse of 
Thales proves the correctness of their calculations ; and then he proceeds to say that 
the researches of Bouvard, Burckhardt, and Wurm, as well as his own, show that 
the secular regression of the node must be diminished 2' (or reduced to 134° 9' 42") ; 
that with this the eclipse of Agathocles was possible, supposing Agathocles near 
Cape Passaro ; that to make the eclipse central there the regression must be further 
diminished (as I understand him) by 18", and to make it barely possible it must be 
increased by 9". But after insisting on the certainty of this correction of the node, 
and after having called attention to his former calculations on the eclipse of Thales, 
he never so much as hints that his former conclusions must now necessarily be 
erroneous. I am wholly unable to account for this extraordinary silence. 
2 B 2 
