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year, is again divided into two; one of them is exact, and measures the entire course of the sun; it is called a tropical year, because it begins with the solstice (called rgons). and determines in 365 days and the fourth part of a day nearly. The other is called a civil year, less accurate than the former, and subservient to popular uses.
The lunar year contains 354 days. This kind of year now in use among the Arabians, Turks, and Saracens.
There are other marks and characters of time, or chronological terms which ought to be explained, as cycle, epacts, &c, on account of their frequent use in history.
A CYCLE is a perpetual circulation and recurrence of the same parts of time. The origin of cycles was thus:The apparent revolution of the sun round the earth has been arbitrarily divided into 24 hours; the basis or foundation of all our mensuration of time. Civil use knows none but hours; or rather multiples of hours, as days and years. But neither the annual motion of the sun, nor that of the other heavenly bodies, can be measured exactly, and without any remainder, by hours, or their multiples. That of the sun, is 365 days, 5 hours, 49 minutes, nearly; that of the moon, 29 days, 12 hours, 44 minutes. Hence, to swallow up these fractions in whole numbers, and yet in numbers which only express days and years, cycles have been invented; which comprehending several revolutions of the same body, replace it, after a certain number of years, in the same points of the heavens, whence it first departed: or, which is the same thing, in the same place of the calendar.
Such is the famous cycle of 19 years, called also the Cycle of the moon, or lunar cycle, a period of 19 solar years; equivalent to 19 lunar years, and 7 intercalary months in which time, the new and full moons are supposed to return to the same day of the Julian year.
This is also called the metonic period, from its inventor Meton, the Athenian; and the golden number.-Though, in propriety, the golden number is rather the particular number which shows the year of the lunar cycle any given year is in. This cycle of the moon only holds true for 312 years: for though the new moons do return to the same day after 19 years; yet not to the same time of the day, but near an hour and a half sooner: which error, in
312 years, amounts to an entire day. Yet those employed in reforming the calendar, went on a supposition of the lunations returning precisely from 19 to 19 years, for ever.
The use of this cycle in the antient calendar, is to show the new moon of each year, and the time of Easter. In the new one, it only serves to find the epacts; which show, in either calendar, that the new moons fall 11 days too late.
Cycle of the sun, or, Solar Cycle, a revolution of 28 years; beginning with 1, and ending with 28; which being elapsed, the dominical or sunday-letters, and those that express the other feasts, &c. return into their former place, and proceed in the same order as before. It is called solar cycle, not with regard to the sun's course, which has nothing to do herein; but from sunday, antiently called dies solis, the day of the sun: because the dominical letter is principally sought for from this revolution; the dominical letters, of which are the first in the alphabet, having been substituted in lieu of the nundinal letters of the Romans.
The reformation of the calendar under pope Gregory, occasioned a considerable alteration of this cycle; in the Gregorian calendar, the solar cycle is not constant and perpetual; because every fourth secular year is common; whereas in the Julian, it is bissextile. The epocha or beginning of the solar cycle, both Julian and Gregorian, is the ninth year before Christ.
To find the cycle of the sun for any given year: add 9 to the number given, and divide the sum by 28; the number remaining will be the number of the cycle, and the quotient the number of revolutions since Christ. If there be no remainder, it will be twenty-eight, or the last year of the cycle.
JULIAN YEAR, is a solar year, containing, commonly, 365 days; though every fourth year, called bissextile, contains 366. The astronomical quantity, therefore, of the Julian year is 365 days, 6 hours, which exceeds the true solar year by eleven minutes; which excess, in 131 years, amounts to a whole day. And thus the Roman year stood, till the reformation made therein by pope Gregory.
For this form of the year we are indebted to Julius
Cæsar: who in the contrivance thereof, was assisted by Sosigenes, a famous mathematician, called over from Egypt for this very purpose; who, to supply the defect of 67 days, which had been lost through the fault of the pontifices, and to fix the beginning of the year to the winter solstice, made that year to consist of 15 months, or 445 days; which for that reason, is called annus confusionis, the year of confusion.
The Gregorian year, is the Julian year corrected by this rule; that, whereas on the common calculation, every secular or hundredth year, is bissextile; on the new calculation, three of them are common years, and only the fourth bissextile. And see Style (new) infra, p. 125.
The Republican Year was introduced into France in 1793'; and though it did not admit of any new astronomical calculations, yet it completely changed the antient form of the year. This year was divided into twelve months, of 30 days each, making in the whole 360 days: in order to complete the ordinary year, five days followed; which were called complementary days. The intercalary day, which was added every fourth year, to the complementary days, was called the day of the revolution; and the bissextile period of four years was designated The Franciade, in order to commemorate the revolution; which, at the expiration of four years from the commencement, had conducted France to a republican government.
This republican year, after being followed in France for 12 years, was suppressed by the Senatus Consultum of Sept. 9, 1805; and the Gregorian calendar was re-adopted with the year 1806.
EPACTS.-The epact is the number of days added to the lunar, to make it equal to the solar, year.
The epacts, then, are either annual or menstrual,
Hence, as the Julian year is 365 days, 6 hours, and the Julian lunar year 354 days, 8 hours, 48 minutes, 38 seconds; the annual epact will be 10 days, 21 hours, 11 minutes, 22 seconds; that is, nearly 11 days. Consequently, the epact of 2 years is 22 days; of 3 years 33 days; or rather 3, since 30 days make an embolismic, or intercalary month.
Thus, the epact of 4 years is 14 days; and so of the rest and thus, every 19th year, the epact becomes 30, or 0; consequently the 20th year, the epact is 11 again; and
so the cycle of epacts, expires with the golden number, or lunar cycle of 19 years, and begins again with the same.
Further, as the new moons are the same, that is, fall on the same day every 19 years, so the difference between the lunar and solar year, is the same every 19 years. And because this difference is always to be added to the lunar year, in order to adjust, or make it equal to the solar year; hence such difference respectively belonging to each year of the moon's cycle, is called the epact of the said year, that is, the number to be added to the said year to make it equal to the solar year.
The 15th day, in March, May, July, and October, and the thirteeuth in the other months, was called, the Ides of these months; Idus Martii, Idus Maii, &c. The 13th day in the 4 months, and the 11th in the 8, was called the third of the Ides of such months, 3 Idus Martii, &c. So the 12th day in the four, and the tenth day in the eight months, were the 4th of the Ides, 4 Idus Martii, &c. And thus of the rest, to the 8th and 6th days, which make the 8th of the Ides, 8 Idus Martii, &c.
IDES, (idus) in, the Roman calendar, a denomination given to eight days in each month; commencing in the months of March, May, July, and October, on the 15th day; and in the other months, on the 13th day; and reckoned backward, so as in the four months above speci fied to terminate on the 8th day, and in the rest on the 6th. The Ides came between the calends and the nones.
This way of accounting is still in use in the Roman chancery, and in the calendar of the breviary. The Ides of May were consecrated to Mercury; the Ides of March were ever esteemed unhappy, after Cæsar's mur der on that day; the time after the Ides of June was reckoned fortunate for those who entered into matrimony: the Ides of August were consecrated to Diana, and were ob served as a feast day by the slaves. On the Ides of September, auguries were taken for appointing the magistrates, who formerly entered into their oth on the Ides of May, afterwards on those of March.
CALENDS, (Calenda,) in the Roman chronology, the
The word is formed from the Latin calo, or rather,
tion of the Roman fast, it was one of the offices of the Pontifices to watch the appearance of the new moon, and give notice to the Rex Sacrificulus; upon which a sacrifice being offered, the pontiff summoned the people together in the capital, and there with a loud voice proclaimed the number of calends, or the day whereon the nones would be; which he did by repeating this formula, as often as they were days of calends, Calo, Juno, Novella. Whence the name Calende was given thereto, from calo, calare. This is the account given by Varro.
NONES, (None) in the Roman calendar, the fifth day of the months January, February, April, June, August, September, November, and December, and the seventh of March, May, July, and October. These four last months having six days before the Nones, and the others only four.
The word apparently has its rise hence, that the day of the Nones was nine days before the Ides, and might be called Nono Idus:
March, May, July, and October had six days in their Nones; because these alone, in the autient constitution of the year by Numa, had 31 days each, the rest having only 29, and February 30. But when Cæsar reformed the year, and made other months contain 31 days, he did not likewise allow them six days of Nones.
LE CHAP. III.—MONTHS AND DAYS.
JANUARY is the first month in the year among the western nations. The word is derived from Januarius, a name given it by the Romans from Janus, one of their divinities, to whom they attributed two faces: because on the one side the first of January looked towards the new year, and on the other towards the old one. The word Januarius may also be derived from janua, a gate; for the first month is, as the gate of the year. Numa Pompilius made January the first month, Romulus' year beginuing the mouth of March.
February is derived from Februa, an old Latin word, for, from the very foundation of the city, we meet with Februa for purification; and Februare, to purge or purify.