CHRONOLOGY.

707

Greeks, Indians, and Clialdieans, as well as the Egyptians, hinot introduced into Rome till the time of Scipio Nasica.

actually known and in use before the name hour was applied toit; as Censorious informs us, that the term was not made use of inRome for 300 years after its foundation ; nor was it known atthe time the XI1 tables were constructed. The eastern nationsdivide the day and night in a very singular manner; the origin ofwhich is not easily discovered. The Chinese have live watchesin the night, which are announced by a certain number of strokeson a bell or drum. By the ancient Tartars, Indians, and Persians,the day was divided into eight parts, each of which containedhours. The Indians on tire coast of Malabar divide the day intosix parts, called najikus; each of these six parts is subdivided into6<J others, called venaigas; the venaiga into 60 birpes ; the birpeinto 10 kenikans; the kenikan into four maltires; the mattire intoeight kanmmas or caignodes; which divisions, according to ourmode of computation, stand as follows.

'Najika, ‘34 hours, Venaiga, 34 minutes, Bir|>e, four seconds,Kenikan, seconds, Mattire, T 's second, Caignode, second.

The Chinese day begins at midnight, and ends with the mid-night following. It is divided into twelve hours, each distin-guished by a particular name and tigure. They also divide thenatural day into 100 parts, and each of these into 100 minutes; sothat the whole contains 10,000 minutes. The modern divisionsof (he hour in use among us are into minutes, seconds, thirds,fourths, &:c. each being a 60th part of the former subdivision. Bythe Chalckeans, Jews, and Arabians, the hour is divided into 10S0scruples; so that one hour contains 60 minutes, and one minute,18 scruples. The division of the day being ascertained, it soonbecame an object to find out a method of indicating the expi-ration of each part. One of the first instruments for effectingthis purpose was the clepsydra or water clock. See Clepsydra.Various kinds of clepsydrae were in use among the Egyptians at avery early period. The invention of the instrument is attributedto Thoth or Mercury, and it was afterwards improved by Ctesi-bius of Alexandria. It was a common measure of time among the

but wascipio JNasica. TheChinese astronomers have long made use of it; and by its meanshave divided the zodiac into twelve parts; but it is a veryinaccurate measure of time, varying, not only accordingto the quantity' of water in the vessel, but according to thestate of the atmosphere. The clepsydra was succeeded by thegnomon or sun-dial.—This, at first, was no more than a stileerected perpendicularly to the horizon ; and it was a long timebefore the principles of it came to be thoroughly understood. The'invention is with great probability attributed to the Babvlonianfc,from whom the Jews received it Before the time of Ahaz, whenwe know that a sun-dial was already erected at Jerusalem. It waslong after the invention of dials before mankind began to formany idea of clocks; nor is it well known at what period they werefirst invented. A clock was sent by Pope Paul l. to Pepin kingof Prance, which at that time was supposed to be the only one inthe world. A very curious one was also sent to Charles theGreat from the khalif Ilaroun Alraschid, which the historians ofthe time speak of with surprise and admiration : but the greatestimprovement was that of Mr. Huygens, who added the pendulumto it. Still, however, the instruments for dividing time werefound to be inaccurate for nice purposes. The expansion of thematerials by heat, and their contraction by cold, would cause avery perceptible alteration in the going of an instrument in thesame place at different times of the year, and much more if car-ried from one climate to another. Various methods have been•Contrived to correct this ; which indeed can be done very effec-tually at land by a certain construction of tin* pendulum ; but at■sea, where a pendulum cannot be used, the inaccuracy is ofconsequence much greater : nor was it thought possible io cor-rt-'ct the errors arising from these causes in any tolerable degree,mttil the late invention of Mr. Harrison’s time-piece, which mayBe considered as making perhaps as near an approach to per-fection as possible.

Of Weeks, li e now proceed to the larger divisions of time,yviiifh more properlV belong to chronology, and which must tiekept on record, as no instrument can be made to point them out.() t these the division into weeks of seven days is one of the mostancient, having taken its rise from the creation of the world. TheGreeks, the ancient Persians, Mexicans, and the inhabitants ofx-athay in the northern parts of China seem to have been ignorant ofdivision into weeks. The week of seven days was adopted

by almost all other nations ; and it is remarkable, that one day intlie week has always been accounted sacred by most nation;.Tims Saturday was consecrated to pious purposes among theJews, Friday by the Turk#, Tuesday by the Africans of Gui-nea, and Sunday bv the Christians. Hence also the origin ofFerial or holidays, frequently made use of in systems of Cbrono-logy.

OJ Months. The next division of time is that of month?.This appears to have been, if not coeval with the creation, atleast in use before the tlood. As this division is naturally pointedout by the revolution of the moon, the months of all nations wereoriginally lunar; until after some considerable advances had beenmade in science, the revolutions of that luminary were comparedwith the sun, and thus the limits of the months tixed with greateraccuracy. The division of the year into 13 months, as beingfounded on the number of full revolutions of the moon in thattime, has also been very general. Sir John Chardin, however,informs us that the Persians divided the year into 34 months ; andthe Mexicans into 18 months of 00 days each; but such unna-tural divisions certainly do not merit the title of months. Themonths generally contained 30 days, or 29 and 3.0 days alternately ;though this rule was far from being without exception. Themonths of the Latins consisted of 16 , 18, 22, or 36 days ; andRomulus gave his people a year of 10 months, or 304 days.The Kamtscbadales divide the year into 10 months; reckoningthe time proper for labour to be nine months, and the winterseason, when they are obliged to remain inactive, only as onemonth. The custom of giving names to the different months isvery ancient, though it appears to have been more modern thanthe departure of the Israelites out of Egypt, as they would other-wise undoubtedly leave carried it with them : but for a considera-ble time after their settlement in Canaan, they distinguished themonths only by their order of first, second, &c. After theirreturn trom the Babylouidi captivity, they adopted the Chaldeannames. Other nations adopted various names, and. arranged themonths according to their fancy. From this last circumstancearises the variety in the dates of the months; for as the year hasbeen reckoned from different signs in the ecliptic, neither thenumber nor the quantity of montlis have been the same, and theirsituation has likewise been altered by the necessary intercala-tions. These intercalations became necessary on account of theexcess of the solar above the lunar year ; and the months com-posed of intercalary days are likewise called embolismal. Theseembolismal months are either natural or civil. By the former,the solar and lunar years are adjusted to one another ; and the latterarises from the defect of the civil year itself. The adar of theJews, which always consists of thirty days, is an example of thenatural embolismal month. The Romans divided their month*into kalends, nones, and ides; which they had a singular methodof reckoning backwards. See Kalends. The 2d, 3d, 4th, 5th,6th, and 7th of March, May, July, and October, were the nonesof these months ; but in tlie oilier months were the 2d, 3d, 4th,and 5th days only. Thus the 5th of January was its nones; the4th was pridie nonarmn ; the 3d, tertio nobarum ; and the 2d,quarto. The ides contained eight days in every month, and werenine days distant from the nones. Thus the 15th dav of thesefour months was the ides, hut in the others the 13th; the 12th waspridie iduum, and tlie 11th tertio idmmi. The ides w ere suc-ceeded by the kalends ; our 14th of Jamiarv, for instance, beingthe 19th of, or before the kalends of Februnrv ; the 15th was fh*IStli of the kalends, and so on till the 31st of January, which waspridie kalendanim ; ami February 1st was the kalends. In Eu-rope, the month is either astronomical or civil. r I he former ismeasured by the motion of the heavenly bodies ; tiic latter con-sists of a certain number of days specified by tlie laws, or civil in-stitutions. The astronomical mqntlis, being, for the most part, re-gulated bv the motions of the sun and moon, are thus divided intosolar and lunar, of which the former is sometimes also calledcivil. 'Flic astronomical solar month is the time which the suntakes up in passing through a sign ot tlie ecliptic. The lunarmonth is periodical, synodical, sidereal, and civil. See Astro-nomy. The synodical lunar month is the time that passes be-tween any conjunction ot the moon with the sun and the conjunc-tion following. It includes the motiou of the sun eastward 'duringthat time ; so that a mean lunation consists of 29 d. 12 h. 44'. 3'.8283. The sidereal lunar month is the time of the mean revolu-tion of the moon with regard to the lixod stars. A* the equinoc,-