3 16 Remarks on Ancient Eclipses. 



see page 247, find the solar equation from the epoch A.C. 747 

 — 24 = 723 years, which at eleven minutes per annum amounts 

 to five days twelve hours thirty-three minutes: add this to the 

 date of the said eclipse, and it will stand equated as under: 



D. H. M. 



A.C. 24 O Pekin April 7 4 11 



Solar equation + 5 12 33 



Equated time 12 16 44 

 The solar equation not amounting to the quantity of one pe- 

 riod does not affect this example. 



The return of this eclipse was in A.D. 8S9 observed by the 

 Grecian astronomers at Constantinople: this being at one period 

 distance, seven whole days must be added to the former equation, 

 and from the sum the lunar difference of four days must be sub- 

 tracted as under: 



D. H. M. 

 A.D. 889 O Constantinople April 3 17 52 

 Solar equation .. .. -f 12 12 33 



16 6 25 

 Lunar difference — 4 



Equated time .. 12 6 25 

 Thus this eclipse returned, after 912 years, within ten hours 

 nineteen minutes of the former. 



The stecond return was in April 1801, and although invisible 

 in England was computed in the Nautical Ephemeris to happen 

 April twelve days sixteen hours twenty-one minutes ; which is 

 one hour and a half of the equated time it was observed 1824 

 years before. Now in the year 1801 the Julian style stood cor- 

 rected by twelve whole days; therefore to bring back the date to 

 the ancient style, twelve days must be deducted, and the date 

 stands as follows : 



D. H. M. 

 A.D. 1801 Eclipse. O.S. April 16 21 

 Solar equation .. .. -f 19 12 33 



20 4 54 

 Lunar difference — 8 



Equated time .. 12 4 54 

 Thus by two equations only these eclipses happened on the 

 very same day, and within a fraction of a day. 



The next example I shall take from the date of the memora- 

 ble and total eclipse of the moon at Arbela, which happened in 



the 



J 



