CHRONOLOGY. 
iiion is, that the return of this period was 
lows that the dominical letter of the suc- 
ceeding year w'illbe G. For Sunday being 
the first day of the preceding year will be 
also the last, and the first Sunday in the 
next year will fall on the seventh day, and 
will be marked by the seventh letter, or G. 
This retrocession of the letters will, from 
the same cause, continue every year, so as 
to make F tlie dominical letter of the third, 
&c. If every year were common, the pro- 
cess would continue regularly, and a cycle 
of seven years would suffice to restore the 
same letters to the same days as before. 
But the intercalation of a day every bissex- 
tile or fourth year, has occasioned a varia- 
tion in this respect. The bissextile year 
containing 366, instead of 365 days, will 
throw the dominical letter of the following 
year back two letters ; so that, as in the 
present year (1808), if the dominical letter 
at the beginning of the year be C, tlie do- 
minical letter of the next year will be, not 
B, but A. This alteration is not effected 
by dropping a letter altogether, but by 
changing the dominical letter at the end 
of February, where the intercalation of a 
day takes place. Thus, in the present year, 
C is the dominical letter in January and 
February, but B is substituted for it in 
March, and continues to be the dominical 
letter through the remainder of the year. 
In consequence of this change every fourth 
year, twenty-eight years must elapse before 
a complete revolution can take place in 
the dominical letter, and it is on this cir- 
cumstance, that the period of the solar cycle 
is founded. A table constructed to shew 
the dominical letters for any given years 
of one of these cycles, will answer for the 
corresponding years in every successive cy- 
cle. The first year of the Christian aera 
corresponds to the ninth of this cycle : if, 
therefore, to any given year of the Chris- 
tian aera nine be added, and the sum be 
divided by 28, the quotient will denote the 
number of the revolutions of the cycle 
since the ninth year B. C. and the remainder 
will be the year of the cycle. If there be 
no remainder, the year of the cycle will be 
the last, or twenty-eight, e. g. Nine being 
added to 1808, makes 1817 ; this sum being 
divided by 28, gives a quotient of 64 for 
the revolutions of the cycle, and a remain- 
der of 25 for the year of the cycle. There 
is another cycle in use called. 
The Cycle of Indiction. It consists of fif- 
teen years, and is derived from tlie Ro- 
mans. Learned men are not agreed as to 
the origin of it, but the most probable opi- 
appointed for the payment of some public 
taxes or tributes. The first year of this 
cycle is made to correspond to the year 
3 B. C. If therefore to any given year of 
the Christian aera 3 be added, and the sum 
be divided by 15, the remainder vrill be the 
year of this cycle. There is however an- 
other mode of calculating it. This cycle 
was established by Constantine A. D. 312 ; 
if therefore from the given year of the 
Christian aera 312 be subtracted, and the 
remainder be divided by 15, the year of 
this cycle will be obtained. In either of 
these ways, if there be no remainder, the 
indiction will be 15. We subjoin an ex- 
ample calculated by each of the methods 
above specified. 
1808 
1808 
3 
312 ' 
15) 1811(120 
15)1496(99 
15 
135 
31 
146 
30 
lo5 
flhe indictiofl forthc 
' present year. 
The Julian Period, some acquaintanoe 
with which is indispensable in the study ot 
chronology, will be easily imderstood from 
the preceding account of the cycles. It is 
formed by the combination of ffie three, by 
multiplying the numbers 28, 19, and 15, of 
the cycles of the sun, moon, and indiction, 
into each other.^ The total of years thus 
produced, is 7980, of which the Julian pe- 
riod consists, at the expiration of which, 
and not sooner, the first years of each of 
those cycles will again come together. This 
period was invented by Joseph Scaliger, as 
one by which all aeras, epochs, and com- 
putations of time might readily be adjusted. 
Tlie first year of the Christian »ra cor- 
responds to the 4714th of the Julian period, 
and it extends as far back as 706 years be- 
yond the common date of the creation 
4004. The year of tlie Julian period cor- 
responding with any given year before or 
since the commencement of the Christian 
aera, may easily be found by the follow- 
ing rule. If the year required be of the 
latter kind, add to it 4713, the number 
of years of the Julian period elapsed before 
the Christian aera, and the sum will be the 
year required. If it be of the former, sub- 
tract the year B. C. from 4714, and the dif- 
ference will give it. 
This period has been esteemed by many 
