CHRONOLOGY. 
554 
until feveral ages had elapfed, that the ufe of weeks was 
received into Greece. We are told by fir George Staun¬ 
ton, that the Chinefe are ftill unacquainted with the week 
of feven days, but divide the year into fix parts, of fixty 
days each. The week was like wife unknown to the an¬ 
cient Perfians and to the Mexicans ; the former having a 
different name for every day of the month, and the latter 
snaking ufe of a cycle of thirteen days. It is remarkable, 
that one day in the week has been accounted facred by 
almoft every nation. Thus Saturday was confecrated to 
pious purpofes among the Jews, Friday by the Turks, 
Tuefday by the Africans of Guinea, and Sunday by the 
Chriftians. Hence alfo the origin of ferta , or holidays, 
frequently made ufe of in fyftems of chronology. The 
Chinefe, however, being unacquainted with the week of 
fe-ven days, have no idea of a labbath, or day of relt. 
The next divifion of time fuperior to weeks, is that of 
months. This appears to_ have been, if not coeval with 
the creation, at leak in ufe before the flood. As this di¬ 
vifion is naturally pointed out by the revolution of the 
moon, the months of all nations were originally lunar; 
until after fome coniiderable advances had been made in 
fcience, the revolutions of that luminary were compared 
with the lun, and thus the limits of the month fixed with 
greater accuracy. The divilion of the year into twelve 
months, as being founded on the number of full revolu¬ 
tions of the moon in that time, has alfo been very ge¬ 
neral; though fir John Chardin informs us, that the Per¬ 
fians divided the year into twenty-four months; and the 
Mexicans into eighteen months of twenty days each. 
The months generally contained thirty days, or twenty- 
nine and thirty days alternately; though this rule was far 
from being without exception. The months of the Latins 
conlifted of iixteen, eighteen, twenty-two, or thirty-fix, 
days ; and Romulus gave his people a year of ten months 
and 304 days. The Kamtl'chatkadales divide the year 
into ten months ; reckoning the time proper for labour to 
be nine months, and the winter feafon, when they are 
obliged to remain inadiive, only as one month. 
The lunar month is either illuminative, periodical, or 
fynodical. Illuminative month, is the interval between the 
firft appearance of one new moon and that of the next 
following. As the moon appears fometimes fooner after 
one change than after another, the quantity of the illu¬ 
minative month.is not always the fame. The Turks and 
Arabs reckon by this month. Lunar periodical month, is 
the time in which the moon runs through the zodiac, or 
returns to the fame point again; the quantity of which 
is 27d. 7h-43m. Sf. Lunar fynodical month, called alfo 
a lunation, is the time between two conjunctions of the 
moon with the fun, or between two new' moons; the 
quantity of which is 29 d. i2h. 44m. 3 k 11 thirds. The 
ancient Romans ufed lunar months, and made them al¬ 
ternately of twenty-nine and thirty days: they marked the 
days of each month by three -terms, viz. Calends, Nones, 
and Ides ; which fee under their refpeCtive names. Solar 
month, is the time in which the fun runs through one en¬ 
tire fign of the ecliptic, the mean quantity of which is 30 d. 
joh. 29m. 5k being the twelfth part of 365c!. 5h. 49m. 
our mean folar year. Aftronomical or natural month, is 
that meafured by fome exaft interval correfponding to 
the motion of the fun or moon. Such are the lunar and 
lolar months above-mentioned. Civil or common month, is 
an interval of a certain number of whole days, approach¬ 
ing nearly to the quantity of fome aftronomical month. 
Thefe may be either lunar or folar. The civil lunar month, 
conlifts alternately of twenty-nine and thirty days. Thus 
will two civil months be equal to two aftronomical ones, 
abating for the odd minutes; and fo the new moon wall 
be kept to the firft day of luch civil months fora long 
time together. This was the month in civil or common 
ule among the Jews, Greeks, and Romans, till the time 
of Julius Caefar. The civil folar month, confuted alter¬ 
nately of thirty and thirty-one days, excepting one month 
of the twelve, which confifted only of twenty-nine days } 
but every fourth year of thirty days. And this form of 
civil months was introduced by Julius Caefar. Under the 
emperor Auguftus, the fixth month, till then from its 
place called Sextilis, received the name Auguftus, now 
Auguft, in honour of that prince; and, to make the com¬ 
pliment ftill the greater, a day was added to it, which 
made it confift of thirty-one days, though till then it had 
only contained thirty days 5 to compenfate for which, a 
day was taken from February, making it confift of twen¬ 
ty-eight days, and twenty-nine every fourth year: and 
fuch are the civil or calendar months now' uled through¬ 
out Europe. 
The'higheft or ultimate familiar divifion of time, is into 
years ; and of thefe there are divers rnea'furements or de¬ 
nominations. The folar year, properly, and by way of 
eminence, fo called, is the fpace of time in which the lun 
moves through the twelve figns of the ecliptic. This, by 
the obfervations of the belt modern aftronomers, con¬ 
tains 363 d. 5I1. 48 m. 48 ft the quantity affumed by the 
authors of the Gregorian calendar is 363d. 5h. 49m. 
But, in the civil or popular account, this year only con¬ 
tains 363 days ; except every fourth year, which contains 
366. The viciflitude of feafons feems to have given oc- 
cafion to the firft notice or inftitution of the folar year. 
Man, naturally curious to know the caufe of trftat diver- 
fity, foon found it was the proximity and diftance of the 
fun ; and therefore gave the name year to the fpace of 
time in which that luminary performed his whole courfe, 
by returning to the fame point of his orbit. According 
to the accuracy in their obfervations, the year of fome 
nations was more perfect than that of others, but none 
of them quite exadl, nor whofe parts did not Ihift with 
regard to the parts of the fun’s courfe. According to 
Herodotus, it was the Egyptians who firft formed the 
year, making it to contain 360 days, which they fubdi- 
vided into twelve months, of thirty days each. Mercury 
Trifmegiftus added five days more to the account. And 
on this footing it is faid that Thales inftituted the year 
among the Greeks ; though that form of the year did not 
hold throughout all Greece. Alfo the Jewifh, Syrian, 
Roman, Perfian, Ethiopic, Arabic, &c. years, were all' 
different. In fa£l, coniidering the imperfedft ftate of aftro- 
nomy in thole ages, it is no wonder that different peopie 
lhould difagree in the calculation of the fun’s courfe. 
The folar year is either agronomical or civil. The agro¬ 
nomical folar year, is that which is determined precifely 
by aftronomical oblervations ; and is of two kinds, tro¬ 
pical, and Jidereal or afral. ‘Tropical or natural year, is 
the time the fun takes in paffing through the zodiac ; 
which, as before obferved, is 363d. 5 h. 48 m. 48 ft or 
363 d. 5h. 49 m. This is the only true or natural year, 
becaufe it always keeps the fame feafons to the fame 
months. Sidereal or ajlralyear, is the Ipace of time the 
fun takes in paffing from any fixed ftar, till his return to 
it again : this conlifcs of 365 d. 5 h. 9 m. 17ft being 20 m. 
29 1. longer than the true folar year. 
The lunar year is the fpace of twelve .lunar months. 
Hence, from the two kinds of fynodical lunar months, 
there arife two kinds of lunar years ; the one agronomical, 
the other civil. Lunar aftronomicalyear conlilis of twelve 
lunar lynodical months; and therefore contains 354d. 
8 h. 48 m. 38ft and is therefore tod. 21 h. 'om. sof. 
fiiorter than the lolar year; a difference which is the 
foundation of the epa£t. Lunar civil year, is either com¬ 
mon or embolifmic. The common lunar year conlifts of 
twelve lunar civil months, and therefore contains 354 
days; and the embolifmic, or intercalary lunar year, con- 
lifts of thirteen lunar civil months, and therefore con¬ 
tains 384 days. Thus far we have conlidered years and 
months, with regard to aftronomical principles, upon 
which the divifion is founded. By this the various forms 
of civil years that have formerly obtained, or that do ftill 
obtain, in divers nations, are to be examined. 
The civil year, is that form of year which every nation 
has contrived or adopted, for computing their time by. 
Or 
