CHRONOLOGY. 



it has become necessary to adjust these 

 periods to each other by certain artificial 

 divisions. Of these divisions, 



The Day claims our first notice. In 

 common speech, a day means that period 

 of time, which is included between the 

 first appearance of light in the morning 

 and the return of darkness in the evening, 

 or during which the sun is visible above 

 the horizon. But the word is used, iu u 

 more comprehensive sense, to denote the 

 time of a complete revolution of the 

 earth round its axis. The former has 

 been denominated a natural, the latter a 

 civil, and sometimes a solar, day. The 

 beginning of the day has been variously 

 reckoned by different nations. The Chal- 

 dseans, Syrians, Persians, and Indians, 

 reckoned the day to commence at sun- 

 rise. The Jews, also, used this method 

 for their civil, but began the sacred day 

 at sun-set : this latter mode was used 

 likewise by the Athenians, the Arabs, 

 the Ancient Gauls, and some other Euro- 

 pean nations. The Egyptians appear to 

 have had several methods of reckoning 

 their day; probably the mode varied in 

 different parts of the country, and in the 

 same place at different periods. The an- 

 cient inhabitants of Italy computed the 

 day from midnight, and in this they have 

 been followed by the English, French, 

 Dutch, Germans, Spaniards, and Portu- 

 guese; modern astronomers, after the 

 Arabians, count the day from noon. 



The day was subdivided by the Jews 

 and Romans into four parts, which they 

 denominated watches or vigils; the first 

 commenced at six in the morning, the 

 Second at nine, the third at twelve, and 

 the fourth at three in the afternoon. The 

 beginning of the first watch was, by the 

 Jews, called the third hour, and so on 

 in succession to the fourth watch, which 

 was reckoned the twelfth hour. The 

 night was divided in a similar manner. 

 Other modes of dividing the day have 

 been in use among different nations; but 

 that which is now most general in civi- 

 lized countries is into 24 equal parts 

 or hours. With respect to the different 

 inventions which have been used for mea- 

 suring or distinguishing the hours of the 

 day, we refer to the articles CLEPSYDRA, 

 CLOCK, SUX-DIAL, &c. 



The Week, is a division of time, of which 

 it may be proper to take some notice be- 

 fore we proceed to the month. Various 

 divisions which might be included under 

 this denomination have obtained in dif- 

 ferent countries. The earlier Greeks 

 divided their month i&to three portions^ 



often days each : the Northern Chinese 

 had a week of fifteen days, arid the Mexi- 

 cans one of thirteen. But the Chaldeans, 

 and most other Oriental nations, have, 

 from time immemorial, used the Jewish 

 week of seven days, which has been 

 adopted by the Mahommedans, and in- 

 troduced, with Christianity, to most of 

 the civilized nations of the world. .In 

 the Old Testament, the term week is oc- 

 casionally applied to a period of seven 

 years, as well as of seven days; and to 

 this it is necessary to attend, in order to 

 understand the passages wherein the 

 word is used in that sense. 



The Month. There can be little doubt, 

 but that this division of time was at first 

 suggested by the phases, or the periodi- 

 cal change in the appearances of the 

 moon, and consequently, that in ancient 

 computations the months were invariably 

 lunar. The difficulty, however, of ad- 

 justing this month to the annual revolu- 

 tion of the earth, led, with the improve- 

 ment of astronomy, to the invention of 

 other divisions uneler this name. Months 

 are now divided into astronomical and 

 civil. The astronomical months, with 

 which chronology is concerned, are mea- 

 sured by the revolutions of the moon, 

 and are either periodical or synodical. 

 The periodical lunar month is composed 

 of the time which elapses between the 

 departure of the moon from any part of 

 her orbit, and her return to the same 

 point, which is 27 days, 7 hours, and 43 

 minutes. The synodical lunar month is 

 reckoned from one conjunction of the 

 sun with the moon to another. This pe- 

 riod is not always the same, being sub- 

 ject to the variation occasioned by the 

 motion of the sun eastward on the eclip- 

 tic : a mean lunation consists of 29 clays, 

 12 hours, and 44 minutes. This was the 

 lunar month mostly in use in ancient 

 times. The civil month is that artificial 

 space of time, by means of which the 

 solar year is divided into twelve parts : 

 these months, which were first ordained 

 by Julius Csesar, consist of thirty, or thir- 

 ty-one days each, with the exception of 

 February, which commonly contains 

 twenty-eight, and every fourth year 

 twenty-iiin6 f days. 



Years. The year may be termed the 

 largest natural division of time. As the 

 diurnal revolution of the earth would na- 

 turally lead to the division into days, and 

 the phases of the moon, with a little at- 

 tention, to that into months, so the an- 

 nual motion of the earth round the sun, 

 which would-be marked by the periodiV 



