401 



This result was founded on the computations of his friend Mayer, 

 who, by the assistance of the best astronomical tables then in use, 

 found that neither the eclipse mentioned by Pliny, Scaliger, Cal- 

 visius, Petavius, or Usher, could possibly be the eclipse alluded to 

 by Herodotus. Mayer calculated all the eclipses from 608 to 556 

 before Christ, and found that of May 603 to be that which best ac- 

 corded in position and magnitude with that described by Herodotus. 



In the Philosophical Transactions for the year 1753, Mr. Costard, 

 by computations similar to those of Mayer, arrived at the same con- 

 clusion with respect to this eclipse ; but nevertheless, by introducing 

 an allowance for the moon's acceleration, which was not attended to 

 by Mayer, he has assigned a path to the centre of the moon's shadow, 

 which Baily observes does not pass over any part of Asia Minor, and 

 consequently is too much to the southward for the eclipse of Hero- 

 dotus. 



Since the improvements which have been made of late years in 

 astronomy, have shown the tables employed by Mayer and by Cos- 

 tard to be extremely defective, even in respect to the mean motions 

 of the sun and moon, as well as the lunar equations ; and since the 

 secular variations derived from the formulae of M. Laplace were wholly 

 unknown at the time when those tables were constructed, and must 

 have an important effect in determining the place of conjunction at 

 so distant a period, the author has been induced to recalculate the 

 elements of several of these eclipses, from the new Tables Astrono- 

 miques, published a few years since by the Bureau des Longitudes in 

 France. These calculations, at full length, together with a map con- 

 taining the paths of the moon's shadow in these eclipses, accompany 

 this paper, for the satisfaction of those who may be interested to 

 enter more minutely into the subject. 



The eclipses here calculated are, first, that of Pliny in May, 585 

 B. C. ; next that of Calvisius, 607 B. C., each of which, as well as 

 that of Bayer, passed too much to the south for the eclipse men- 

 tioned by Herodotus ; while that of Petavius, in July, 597, and that 

 of Usher, September, 601 B. C., passed much too far to the north to 

 have been seen in Asia Minor. With respect to the eclipse of the 

 year 626, suggested by Volney, it was not total, but only annular, 

 and moreover was not visible but to countries far eastward of Asia 

 Minor. 



Mr. Baily's inquiries have consequently taken a greater range than 

 those of his predecessors. He has taken the pains to calculate all 

 the solar eclipses from 650 before Christ to 580, and has found only 

 one that was central and total in or near any part of the peninsula 

 of Asia Minor. 



This eclipse took place on the 30th of September, 610. The centre 

 of the moon's shadow, in this instance, passed in the forenoon of 

 that day, in a straight line, over the north-eastern part of Asia Minor, 

 through Armenia into Persia, where the sun was centrally eclipsed 

 on the meridian. The path of the moon's shadow is estimated by 

 the author to have passed over the very mouth of the river Halys, 



