462 Astronomical and Nautical Collections. 



Egyptian year 

 of Nabonassar. 



888, Phamenoth (VII.) 18, (Vol. 2. p. 167. H.) The 4th of An- 

 tonine, the 18-19 Phamenoth, Ptolemy observed the greatest 

 elongation of Mercury in longitude 13j°YJ : the distance from 

 the mean place of the sun 26^°. ^© + 14ly-47.64^ 



888, Pachon (XI.) 7, (p. 161. H.) Ptolemy found, in the 463d 

 year after the death of Alexander, the vernal equinox on the 

 7th of Pachon, one hour after noon. See 887. 



©+141y+0.96^ 



1112, Phamenoth (VII.) 6, (Theon, p. 284, 277, 281. B.) An 

 eclipse of the moon was observed by Theon the commentator, 

 6-j'j^ hour after noon of the 6 Phamenoth, or 7-^^ hours appa- 

 rent time : the moon being in y 28° 15' 10". 



^ + 365y-113.9^ 



This was *'the 81st year of Diocletian, according to the 

 Alexandrians in the month of Athyr, but according to the Egyp- 

 tians, the 81st year in the month of Phamenoth." " The con- 

 junction which took place in the month Thoth, was on the 

 24th, according to the tables, and reckoning back 97 for the 

 difference of the years, we have the 22 Payni of the preceding 

 year for the Alexandrian date, since 24-1-365-97 = 389 — 97 

 = 292." The Alexandrian year having been introduced in 

 723 of Nabonassar, we have 1112-723 = 389=:4x 971 And 

 in the same manner the 6 Phamenoth, deducing 97 days, gives 

 the 29th of Athyr, which was the Alexandrian time of the eclipse. 

 The preceding conjunction was, according to the tables, on the 

 21 Mechir. 



It follows that the years of Diocletian are found by deduct- 

 ing 1031 from those of Nabonassar, and that the first of Dio- 

 cletian was 1032 of Nabonassar. Heraclius says that there 

 were 313 from the 1 Augustus, to the 1 Diocletian, and 

 719 + 313=1032. 



We are informed in the same chapter of Theon, (p. 280.) 

 that the *' table of cities'* gives the longitudes East from the 

 " Fortunate islands ;" and we are directed to take out of it 

 the difference of the longitude of a given place from that of 

 Alexandria, in order to find the time of that place. 



In Heraclius's example of Alexandrian time for the 77th of 

 Diocletian, the time reckoned from the 5th of Augustus is 385 

 years, or 4 x 96 J, and 96 days are deducted. P. 111. See 723. 

 1223, Athyr (III.) 21, (Halma, Vol. 3. p. 11.) The 192d year of 

 Diocletian, the 21 Athyr, the moon was observed by Thius at 

 Athens to pass over Venus, in 13° T^, and 48° from the sun. 

 This would be ,0 +477^-246^ 



But the longitude of Venus being 283°, that of the sun should 

 have been 235°, or 331°, which it could not be 246 days before 



