Lecture XXVIII.

LECTURE XXVIII.

Of the Divifion of TIME, and its
Parts.

HE Parts of Time are known to all Men; being Days, Hours, Weeks, Months, and Years. A natural Day is determin- A natural ed by the apparent Motion of the Sun Day. from Eaft to Weft, and is that Space of Time that flows while the Sun goes from any Meridian, or horary Circle, till it arrives to the fame again. It is called natural, to distinguish it from that Signification of the Word Day, which is oppofed to Night, and which are called the artificial Day.

ÁLL Nations do not begin their Day alike. The The different Babylonians counted the Beginning of their Day Beginnings from the Sun-rifing. The fews formerly, and the of the Day. Athenians, from Sun-fetting; which the Italians, Auftrians, and Bohemians, do at this Time; fo that when the Sun comes to the Western Horizon, they count the twenty-fourth Hour; and the Hour after the Sun is fet, they call the first Hour.

THEY Who begin their Day at Sun-rifing, have this Advantage, that their Hours tell them how much Time is already gone fince Sun-rifing; and they who reckon their Hours from Sun-fetting, have this Ufe of it, that they know how long it is to Sun-fetting, that they may proportion their Journies and Labours for that Time. But both of them have this Inconvenience,

A a 4

Lecture venience, that they cannot immediately tell by their XXVIII. Hours the Times of Mid-day or Mid-night, but they

muft compute by the Length of the Day-time, or the Seafon of the Year; for in different Seasons, the Time of Mid-day is reckoned by different Hours. The Egyptians antiently began their Day at Mid-night, from whom Hipparchus, that antient and famous Aftronomer, brought that Way of reckoning into Aftronomy. And Copernicus, and fome other Aftronomers, have followed him therein. But the much greater Part of the Aftronomers have thought it better to begin their Day from Noon. Yet the Method of Beginning from Mid-night is received in Britain, France, Spain, and most of the Nations in Europe.

THERE are two Sorts of Hours, equal and unequal. An equal Hour is the twenty-fourth Part of the natural Day. Befides the Divifion of Hours received by the Vulgar into half Hours, Quarters, and half Quarters, we now generally follow the Aftronomical Divifion, and reckon every Hour 60 Minutes, in every Minute 60 Seconds, and in every Second 60 Thirds, &c.

AN unequal Hour is the twelfth Part of the artificial Day, or the twelfth Part of the Night; and it is called the temporary Hour, because at different Seafons of the Year, it is of a different Length. For a diurnal Hour in the Summer is longer than one in the Winter; a Night Hour is fhorter. But in the equinoctial Day, the Hours in the Day and Night are equal to each other; and therefore the equal Hours are called Equinoctial. The Jews and Romans formerly ufed thefe Hours, and the Turks reckon by them at this Day, and their Noon always falls upon the fixth Hour of the Day. Thefe Hours are alio called planetary Hours, because in every Hour they fuppofed one of the feven Planets to prefide over the World, and they took it by Turns; fo that the firft Hour after Sun-rifing fell on Sunday to the Sun, the next to Venus, the third to Mercury; and the reft in order to the Moon, Saturn, Jupiter, and Mars. By this Means, on the first Hour of the next Day the Moon prefided, and on that. Account

Account gave the Name to that Day; and the Lecture Days of the Week by this Method, have had their XXVIII. Names from the Planet that governed the first w Hour, 'till the End of the Week.

A Week is a System of feven Days, in which A Week. each Day is diftinguished by a different Name. The Chriftian Church called the first Day of the Week the Lord's Day, the Vulgar term it Sunday, and none but the Phanaticks of our Time ever called it Sabbath-day. The rest of the Days of the Week were called Feria, Munday the fecond Feria, Tuesday the third Feria, &c. and Saturday they alfo called the Sabbath-day. But the common People use the fame Names that were given by the Romans; each Day being denominated from a Planet.

A Month is properly that Space of Time the 4 Month. Moon takes to perform its Course in the Zodiack ; which, in the Space of a Year, it runs over twelve Times. There is another Month nearly equal to it, which is measured by the Motion of the Sun, and is that Space of Time, in which the Sun moves through one Sign, or twelfth Part of the Ecliptick: Thefe Months are properly Aftronomical. A Civil Month is different from them, and confifts of a çertain Number of Days, fewer or more according to the Laws and Ordinances of the Kingdom or Republick, in which they are obferved. The Eggptians made each Month to confift of 30 Days, and the Year confifting of 5 Days more than 12 Months, they added them to the End of the Year, and called them Epogamena.

THE Year is either Aftronomical or Civil; The Civil both Kinds of the Aftronomical Years, viz. the Year of twe Tropical and Periodical, we have already defined Sorts. in our XXII Lecture. The Civil Year is the fame with the Political Year, eftablished by the Laws of a Country, and is of two Kinds, Lunar or Solar, according as it is defigned to be regulated by the Motions of the Moon or Sun. There are two Sorts of Lunar Years, the one moveable,