708

CHRONOLOGY.

tu.l points go backwards about -1“ io the space of a lunar month,the moon nurd, in consequence of this retrocession, arrive at theequinox sooner than at any lived star, and consequently themean sidereal revolution nnst be longer than the mean pe-riodical or.e. The latter consists of 27 d. 7 h. 43'. 4'. (1840.The civil lunar month is computed from the moon, to answer theordinary purposes of life ; and as-it would have been inconveni-ent, in the computation of lunar months, to have reckoned oddparts of days, they have been composed of thirty days, or oftwenty-nine and thirty alternately, as the nearest round numbers.When the month is reckoned from the iir.->t appearance of themoon after her conjunction, it is called the month of illumination.The Arab*, Turks, and other nations, who use the ara of theHegira, follow this method of computation. As twelve lunarmouths, however, are eleven days less than a solar year, JuliusCu'sar ordained that the month should be reckoned from thecourse of the sun,-and not of the moon; and that they shouldconsist of thirty and thirty-one days alternately, February onlyexcepted, which was to con Ft of twenty-eight slays commonly,hnd of twenty-nine in leap-years.

Of Years. The regular returns of the seasons suggested thisnatural divi-ion of time into years. As the eastern nations, parti-cularly the Egyptians, Chaldeans, and Indians, applied themselvesvery < al ly to astronomy, they found, bv comparing the motionsof the sun and moon together, that one revolution of the formerincluded above twelve of the latter. Hence a year of twelve lu-nations was formed, in every one of which were reckoned thirtydays ; and hence probable the division of the ecliptic into 36 bdegrees. The limi-solar year, consisting of 360 days, was in uselong before any regular intercalations were made ; and historiansinform us, that the year of all ancient nations was limi-solar. He-rodotus relates, that the Egyptians first divided the year into 12parts by the assistance of the stars, and that every part consistedof 30 days. The Thebans corrected this year by adding five in-tercalary days to it. The old Chaldean year was reformed by theModes and Persians ; and some of the Chinese missionaries haveinformed us, that the luni-solar year was also corrected in Ch.na ;that the solar year was ascertained in that country to very consi-derai'le exactness. The Latin year, before Numa’s correction ofIt, consisted of 300 days, of which 304 were divided into tenmonth, ; to which were "added two private months not mentionedin the kalendar.... The imperfection of this method of computingtime is now very evident. The limi-solar year was about 5£ daysshorter than the true solar year, and as much longer than the lunar.H ence the months could not long correspond with the seasons ;and even in so short a time as 34 years the winter months wouldhave changed places with those of summer. From this rapidvariation, Mr. Playfair takes notice that a passage in Herodotus,bv which the learned have been exceedingly puzzled, may re-ceive a satisfactory solution, viz. that “ in the time of tiie ancientEgyptian kings, the sun had twice arisen in the place where it,liad formerly set, and twice-set where it had arisen.” By this hesupposes it is meant, “ that the beginning of the year had twicegone through all the signs of the ei liptic ; and that the sun hadrisen and set twice, in every day and month of tile year.” This,which some have taken fora proof of most extravagant antiquity,lie further observes, might have happened in 138 years only ; asin that period there would be a difference of nearly two yearsbetween the solar and lunar year. Such evident imperfectionscould not but produce a reformation every where ; and accord-ing! v we find that there was no nation which did not add a fewintercalary days at certain intervals. We are ignorant, how-ever, of the person who was the first inventor of Ibis method.The Theban priests attributed the invention to Mercury or Tliolli;and it is certain 1 hat they were acquainted with the year of 365<ia\s at a very early period. The length of the solar year was•represented by the celebrated golden circle of Osymandyas of365 cubits circumference; and on every cubit of which was in-scribed a day of the year, together with tlu: heliacal risings andsettings of the stars. 'Phis monarch is'supposed to iiavo reignedm the 11th or 13th century before the Christian era. The Egyp-tian solar year being nearly six hours shoi ter than the true one,this inaccuracy, in time, produced another revolution ; some cir-cumstances attending which serve to li.\ the date of the discoveryof the length ot the year, and which from the above descriptionot the golden circle, we may suppose to have been nude during

the reign of Osymandyas. The inundation of the Nile was annu-ally announced by the heliacal rising of Sirius, to which the re-iormers of the kalendar adjusted the beginning of the year, sup-posing that it would remain immoveable. In a number of years,however, it appeared that their suppositions in this were ill-found-ed. By reason of the inequality above-mentioned, the heliacalrising of Sirius gradually advanced marly at the rate of one day infour years ; so that in 1461 years it completed a revolution, byarising on every succeeding day of the year, and returning tothe point originally fixed for the beginning of the year. Thisperiod, equal to IsoO Julian years, was termed the great Egyptianyear, or Canicular cycle. From the accounts we have of thetime that the canicular cycle was renewed, the time of its originalcommencement may lie gathered with tolerable certainty, l’hishappened, according to Censorious, A. I). 138. Beckoningbackward therefore from this time for 1460 years, we come toB. C. 1322, when the sun was in Cancer, about 14 or 15 daysafter the summer solstice, which happened on July 5. The Egyp-tians used no intercalation till the lime of Augustus, when the cor-rected Julian year was received at Alexandria by his order; huteven this order was obeyed only by tire Greeks and Romans whoresided in that city ; the superstitious natives refusing to makeany addition to the length of the year, which had been so longestablished among them. At what precise period the true yearwas observed to consist of nearly six haul’s more than 365 days,is quite uncertain. Though the priests of Thebes claim the meritof the discovery, Herodotus makes no mention of it; neither didThales, who introduced the year of 365 days into Greece, everuse any intercalation : Philo and Eudoxus are said to have ob-tained it as a secret from the Egyptians about 80 years afterHerodotus, and to have carried it into Greece ; which showed,that, the knowledge of this form of the year was at that timerecent, and confined to a few learned men. The ancient Jewishyear was lunisolar ; and we are informed by tradition, that Abra-ham preserved in his family, and transmitted to his posterity,the Chaldean form of the year, consisting of 360 days; whichremained thp same without any correction until the date of theana of Nabonassar. The solar year was adopted among themafter their return from the Babylonish captivity : hut when sub-jected to the successors of Alexandria in Syria, they were obligedto admit the lunar year into .their kalendar. To adjust this yearto the course of the sun, they added at certain periods a monthto Adar, and called it Ye-Adar. They composed also a cycleof 19 years, in seven of which they inserted the intercalary month.This correction was intended to regulate the months in such amanner, as to bring the 15th of Nisan to the equinoctial point:and likewise the courses of the seasons and feasts in such a manner,dial the corn might be ripe at the passover as the law required,'I he Homan year instituted by Romulus, was evidently very im-perfect, when Numa undertook to reform it. To make a com-plete lunar year, lie added 50 days to the 304 of Romulus ; andfrom every one of his months, which consisted of 31 and 30 days,lie borrowed one day. Of these additional (iO days lie composedtwo months ; calling the one January, anil the oilier February.Various other corrections were made: but when Julius Casarobtained the sovereignty of Borne, lie found that the mouths hadconsiderably receded from the seasons to which Numa had ad-jured them. To bring them forward to their places, lie formeda year of 15 months, or 445 days; which, on account of itslength, and the design with which it was formed, has been calledthe yeflr of confusion. It terminated oil the first of January,A. C. 45, and from this period the civil year and months were| regulated by the course of the sum The year of Numa beingten days shorter than tile solar year, two days were added byJulius to every one of the months of January, August, and De-cember, and one to April, June, September, and November.He ordained likewise, that an. intercalary day*should be addedevery 4th year to the month of February, by reckoning the 24thday, -or sixth of the kalends of March, twice over. lienee thisyear was styled bissextile, or twice sextile, and also leap year,irom its leaping a day more than a common year. 'Tire Julianyear lias been used by modern chronologers, as being a measureof time extremely simple and sufficiently accurate. it is still,how ever, somewli.it imperfect ; for as the true solar year consistsof 365 d. 5 li. 48' 48", it appears that in 131 years after thelJulian correction, the sun must have arrived one day loo soon