The _Babylonians_ began their day at Sun-rising, and reckoned 24 hours ’till he rose again! This way of computation we call the _Babylonish Hours_. In several parts of _Germany_ they count their hours from Sun-setting, calling the first hour after the Sun has set, the first hour, _&c._ ’till he sets the next day, which they call the 24th hour: These are commonly called the _Italian Hours_. According to both these ways of computation, their hours are commonly either a little greater or less than the ¹/₂₄ part of a natural day, in proportion as the Sun rises or sets sooner or later in the succeeding days. They have also this inconvenience, that their mid-day and midnight happen on different hours, according to the seasons of the year. [Sidenote: _Jewish Hours._] [Sidenote: _Planetary Hours._] The _Jews_ and the _Romans_ formerly divided the artificial days and nights each into 12 equal parts; these are termed the _Jewish Hours_, and are of different lengths, according to the seasons of the year; a _Jewish Hour_ in summer being longer than one in winter, and a night-hour shorter. This method of computation is now in use among the _Turks_, and the hours are stiled the _first hour_, _second hour, &c._ of the day or night; so that _Mid-day_ always falls on the sixth hour of the day. These hours are also called _Planetary Hours_, because in every hour one of the seven Planets were suppose to preside over the World, and so take it by turns. The first hour after Sun-rising on _Sunday_ was allotted to the _Sun_; the next to _Venus_, the third to _Mercury_; and the rest in order to the _Moon_, _Saturn_, _Jupiter_, and _Mars_. By this means on the first hour of the next day, the Moon presided, and so gave the name to that day; and so seven days by this method had names given them from the Planets that were supposed to govern on the first hour. [Sidenote: _A Week._] A _Week_ is a system of seven days, in which each day is distinguished by a different name. In most countries these days are called after the names of the seven Planets, as above noted. All nations that have any notion of religion, lay apart one day in seven for public worship; the day solemnized by _Christians_ is _Sunday_, or the first day of the week, being that on which our saviour rose from the grave, on which the apostles afterwards used more particularly to assemble together to perform divine worship. The _Jews_ observed _Saturday_, or the seventh day of the week, for their sabbath, or day of rest, being that appointed in the fourth commandment under the Law. The _Turks_ perform their religious ceremonies on _Friday_. [Sidenote: _A Month._] [Sidenote: _Periodical_ and _Synodical Month_.]