172 J. W. French on a new Period in Chronology. 
Art. XVII.—On a new Period in Chronology, called the Precession 
Period ; by J. W. Frencu. (In a letter to the Editors.) 
I PROPOSE in the place of the Julian Period in chronology, 
another which I will call the Prevession-Perio 
This latter will be found to have all the alerting of the 
other without its defects, and is dacs these comparative utilities, 
to have chronological uses of its own which are great and vari 
ous, both for the exwbnnin of eas: and for the vast cycles 
ape by science. 
ns Pariah i in chronology consists of 7,980 Julian 
years, i cae oie being formed by the continual multiplica- 
tion of 28,19 and 15; that is to say, of the cycle of the sun, the 
cycle of the moon, and the eycle of indiction. The first year 
of the Christian Era is made the 4,714th of the Julian Period. 
By such an arrangement we can find for any year its golden 
number, its number for the solar cycle, and that for its Roman 
Indiction. Also, we have a fixed period reaching back in history . 
among the local and broken — of different peoples and 
countries. These certainly are great advantages, and have se- 
cured for that Period acceptance and commendation. 
But some of its defects are these. 1. It has an artificial ele- 
ment, that of the Roman Indiction, instead of having its found- 
ation wholl y in astronomy. 2. It is soon exhausted, and in 
the past, it does not reach far enough even for the Septuagint 
Chronology in history. 3. It furnishes no unit nor cycle for 
seience. 
The period which I ge anne is founded wholly on astronomy, 
is exhaustless by being recurrent, has its initial pom sufficient- 
ly far back for any sun rable historical purposes, gives to sci- 
ence a worthy umit for the vast durations it contemplates, and 
with these inestimable advantages, has the two practical utilities 
of the Julian Period ;—that of giving the elements needed in 
the almanac for every year, and that - extending into the past 
a long and unaltering standard for ti 
I propose to take, as : the iivelioaiae pi the time for the preces- 
sion of the equinoxes, 25,872 years. By a singular felicity, that 
number can be formed from the factors 28, 84, and 11. Now 
28 is the number of the solar cycle; 84 is a lunar cycle em- 
ployed formerly by the Jews, and havi peculiar uses in esti- 
ma ong series of lunations. The oth i 
nar cycle employed by the early Christians, the errors of whieh 
_ exactly counteract those of the cycle of 84years. These 
e multiplied together form 25,872. A subordinate felicity 
will at once be seen by a complete mathematician. The num- 
ber 25,872 can be divided and subdivided to the last, without a ré- 
mainder, by a large number of divisors. 
