533 
CHRONOLOGY. 
framing a new calendar, perfuaded the Chriftians of the 
weft to come into the practice of the church of Alex- 
dria. To determine the year of the lunar cycle, is the fame 
as to find the golden number. 
1801 
29)1802(94. 
171 
92 
76 
Gol.No. ifi 
To find the golden number ; add 1 to 
the given year, and divide the fum by 
i 9 , and what remains will be the gold¬ 
en number; unlefs o remains, for then 
19 is the number 
Thus, the golden number for the 
year 1801 is 16 ; as by the operation in 
the margin. _ 
The cycle of the fun, or folate cycle, is a period or revolu¬ 
tion of twenty-eight years; beginning with 1, and end¬ 
ing with 28 ; which elapfed, the dominical or funday- 
letters, and thofe that exprefs the other feafts, &c. return 
again into their former place, and proceed in the fame 
order as before. The days of the month likewife return 
again to the fame days of the week ; the fun’s place to 
the fame figns and degrees of the ecliptic on the fame 
months and days, fo as not to differ one degree in a 
hundred years ; and the leap years begin the fame courfe 
with refpedt to the days of the week on which the days 
of the month fall. This is called the cycle of the fun, or 
the folar cycle, not from any regard to the fun’s courfe, 
which has no concern in it; but from Sunday, anciently 
called dies foils, the fun s day ; as the dominical or funday 
letter is chiefly fought for from this revolution. The re¬ 
formation of the calendar under pope Gregory XIII. oc- 
cafioned a confiderable alteration of this cycle: in the 
Gregorian calendar, the folar cycle is not conftant and 
perpetual ; becaufe every 4th fecular year is common ; 
whereas, in the Julian, it is biflextile. The epoch, or 
beginning of the folar cycle, both Julian and Gregorian, 
is the gth year before Chrift. And therefore, to find the 
cycle of the fun for any g'vven year : add 9 to the number 
given, and divide the fum by 28 ; the remainder will be 
the number of the cycle, and the quotient the number of 
revolutions fince Chrift. If there be no remainder, it will 
be the 28th or laft year of the cycle. 
The Chinefe cycle is a lunar cycle of fixty years, calcu¬ 
lated to bring, in that period, a perfect coincidence of 
the relative politions of the fun and moon. This has 
been lately exhibited by Sir George Staunton, in whole 
opinion it tends to Ihew, by an analytical review of its 
feries, that the Chinefe empire exifted at leaft 2277 years 
before the Chriftian era.—See this explained under the 
article China, p. 438 of this volume. 
But the principal regulator of chronological events is 
the Julian period, fo called as being adapted to the Julian 
year, and is a feries of 7980 Julian years ; ariling from 
the multiplications of the cycles of the fun, moon, and 
indifition, together, or the numbers 28, 19, 15; com¬ 
mencing on the ill day of January in the 764th Julian 
year before the creation, and therefore is not yet com¬ 
pleted. This comprehends all other cycles, periods, and 
epochs, with the times of all memorable actions and hif- 
tories; and therefore it is not only the moft general, but 
the moft ufeful, of all periods, in chronology. As every 
year of the Julian period has its particular folar, lunar, 
and indiftion, cycles, and no two years in it can have all 
tilde three cycles the fame, every year of this period be¬ 
comes accurately diftinguilhed from another. This pe¬ 
riod was invented by Jofeph Scaliger, as containing all 
the other epochs, to facilitate the reduction of the years 
of one given epoch to thofe of another. It. agrees with 
the Conftantinopolitan period, ufed by the Greeks, ex¬ 
cept in this, that the cycles of the fun, moon, and indic¬ 
tion, are reckoned differently; and alfo in that the firft 
year of the Conftantinopolitan period differs from that of 
the Julian period. 
The Confi antinopolitan period, is that ufed by the Greeks, 
and is the fame as the Julian period above deferibed. 
The Callippic period is a feries of feventy-fix years, at 
every repetition of which, it was fuppofed, by its inventor 
Calippus, an Athenian aftronomer, that the mean new 
And full moons would always return to the fame day and 
hour. About a century before, the golden number, or 
cycle of 19 years, had been invented by Meton, which 
Callippus finding to contain 19 of Nabonaffar’s years, 4 
days and to avoid fraftions he quadrupled it, and 
thus produced his period of 76 years, or 4 times 19 ; after 
which he fuppofed all the lunations, &c. would regularly 
return to the fame hour. But neither is thjs exa6h, as 
it brings them too late by a whole day in 225 years. 
Hipparchus's period, is a feries or cycle of 304 folar 
years, returning in a conftant round, and reftoring the 
new and full moons to the fame day of the lolar year ; 
as Hipparchus thought. This period arifes by multiply¬ 
ing the Calippic period by 4. Hipparchus affumed the 
quantity of the folar year to be 363d. 5h. 55m. 12ft and 
hence he concluded, that in 304 years Calippus’s period 
would err a whole day. He therefore multiplied the pe¬ 
riod by 4, and from the product call away an entire day. 
But even this does not re (tore the new and full moons to 
the feme day throughout the whole period : but they 
are fometimes anticipated id. 8I1. 23m. 29f. 20 thirds. 
The Fiflorian period, is an interval of 532 Julian years; 
at the end of which, the new and full moons return again 
on the fame day of the Julian year, according to the 
opinion of the inventor, Viclorinus, or Viftorius, who 
lived in the time of pope Hilary. Some aferibe this pe¬ 
riod to Dionyfius Exiguus, and hence they call it the 
Dionyfian period : others again call it the great pafchal 
cycle, becaufe it was invented for computing the time of 
Eafter. The Viflorian period is produced by multiply¬ 
ing the folar cycle 28 by the lunar cycle 19, the product 
being 532. But neither does this reftore the new and 
full moons to the lame day throughout its whole dura¬ 
tion, by id. 16I1. 58m. 59ft 4-othirds. 
Of the DATES or ERAS of TIME. 
Independent of the preceding cycles or periods for the 
meafurement of time, chronologers have certain points 
or data from which they begin to reckon, which points 
or roots of time are called eras. The moft remarkable 
of them are, thofe of the creation, the Greek Olympiads, 
the building of Rome, the era of Nabonnaflar, the death 
of Alexander, the birth of Chrift, the Arabian Hegira, or 
flight of Mahomet, the Perfian Jefdegird, and the Spanilh 
era, all which,.with a few others of iefs note, have their 
beginnings fixed by chronologers to the years of the Ju¬ 
lian period, to the age of the world, and to the years be¬ 
fore and after Chrift. 
The Olympiad is a revolution or period of four years, 
by which the Greeks reckoned their time : lo called from 
the Olympic games, which were celebrated every fourth 
year, during five days, near the iummer folftice, upon 
the banks of the river Alpheus, near Olympia, a town of 
Elis. As each Olympiad confilled of four years, thefe 
were called the firft, lecond, third, and fourth, year of 
each Olympiad ; the firft year commencing with the near- 
ell new moon to the trimmer folftice. The firft Olympiad 
began the 3938 year of the Julian period, the 3208 of the 
creation, 776 years before the birth of Chrift, and 24 years 
before the foundation of Rome. And the computation 
by thefe, ended with the 404th Olympiad. 
The era of Nabonaffar is a Jewilli era, which began on 
Wednefday February 26th, in the 3267th year of the Ju¬ 
lian period, or 747 years before Chrift: in this reckon¬ 
ing the years are Egyptian ones, of 365 days each. This 
is a remarkable era in chronology, becaufe Ptolomy af- 
fures us there were aftronomical obfervations made by 
the Chaldeans, from the reign of Nabonaffar to his time 3 
alfo Ptolomy, and other aftronomers, account their years 
from that epoch. 
The era of Chrifi, is the common era throughout Eu¬ 
rope, commencing at the fuppofed time of cur Saviour’s 
nativity, December 25 ; or rather, according to the ufuai 
account, from his circumcifion, or the 1 It of January, 
The author of this epoch was an abbot of Rome, one 
Dionyfius 
