November, the ninth month in the year of Romulus, (whence its name) is the eleventh of the Julian year.

December, (from Decem,) was the tenth month of the year of Romulus. And it is the last now with us, being the period of the winter solstice.

A month is divided into four parts called weeks, each consisting of seven parts called days. Of these months there are thirteen in a Julian year, and one day over; of weeks there are fifty-two, and of days three hundred and sixty-five, as before observed.

The days of the week are SUNDAY, from the Sun; MONDAY, from the Moon; TUESDAY, from Tuisco, a Saxon hero; WEDNESDAY, from Woden, the god of battle; THURSDAY, from Thor, the god of winds; FRIDAY, from Friga, the goddess of peace; and SATURDAY, from Sator, the god of freedom.

The Romans divided their months into calends, nones, and ides; calling the first day of every month its calends.

The Romans called the days of the week after the planets:-as dies Solis, day of the sun; dies Lunæ, day of the moon; dies Martis, day of Mars; dies Mercurii, day of Mercury; dies Jovis, day of Jove; dies Veneris, day of Venus; dies Saturni, day of Saturn.

A True Solar Day is the time from the sun's leaving the meridian of any place, on any day, till it returns to the same meridian on the next day; viz. it is the time elapsed from twelve o'clock at noon, on any day, till twelve o'clock at noon on the next day, as shewn by a correct sun-dial.

A true solar day is subject to continual variation, arising from the obliquity of the ecliptic, and the unequal motion of the earth in its orbit; the duration thereof sometimes exceeds, at others, falls short, of twenty-four hours, and the variation is the greatest about the first of November, when

the true solar day is 16" 15" less than twenty-four hours, as shewn by a well regulated clock.

A mean Solar Day is measured by equal motion, as by a clock or time-piece, and consists of twentyfour hours. There are in the course of a year as many mean solar days as there are true solar days, the clock being as much faster than the sun-dial on some days of the year, as the sun-dial is faster than the clock on others.

Thus the clock is faster than the sun-dial from the twentyfourth of December to the fifteenth of April, and from the sixteenth of June to the thirty-first of August: but from the fifteenth of April, to the sixteenth of June, and from the thirty-first of August to the twenty-fourth of December, the sun-dial is faster than the clock. When the clock is faster than the sun-dial, the true solar day exceeds twenty-four hours; and when the sun-dial is faster than the clock, the true solar day is less than twenty-four hours; but when the clock and the sun-dial agree, viz. about the fifteenth of April, sixteenth of June, thirty-first of August, and twentyfourth of December, the true solar day is exactly twenty-four hours.

The Astronomical Day, is reckoned from noon to noon, and consists of twenty-four hours. This is called a natural day, being of the same length in all latitudes.

The Artificial Day is the time elapsed between the sun's rising and setting, and is variable according to the different latitudes of places.

The Civil Day, like the astronomical or natural consists of twenty-four hours, but begins differently in different nations.

The ancient Babylonians, Persians, Syrians, and most of the eastern nations, began their day at sun-rising. The ancient Athenians, the Jews, &c. began their day at sun-setting, which custom is followed by modern Austrians, Bohemians, Silecians, Italians, Chinese, &c. The Arabians begin their day at noon, like the modern astronomers. The ancient Egyptians, Romans, &c. began their day at midnight, and this method is followed by the English, French, Germans, Dutch, Spanish, and Portuguese.

A Sidereal Day is the interval of time from the

passage of any fixed star over the meridian, till it returns to it again: or, it is the time which the earth takes to revolve once round its axis, and consists of twenty-three hours, fifty-six minutes, four seconds, of mean solar time.

In elementary books of astronomy and the globes, the learner is generally told that the earth turns on its axis from west to east in twenty-four hours; but the truth is, that it turns on its axis in twenty-three hours, fifty-six minutes, four seconds, making about three hundred and sixty-six revolutions in three hundred and sixty-five days, or a year. The natural day would always consist of twenty-three hours, fiftysix minutes, four seconds, instead of twenty-four hours, if the earth had no other motion than that on its axis; but while the earth has revolved eastward once round its axis, it has advanced nearly one degree eastward on its orbit. To il lustrate this, suppose the sun to be upon any particular meridian at twelve o'clock, on any day; in twenty-three hours, fifty-six minutes, four seconds afterwards the earth will have performed one entire revolution; but it will at the same time have advanced nearly one degree eastward, in its orbit, and consequently that meridian which was opposite to the sun the day before, will now be one degree westward of it; therefore the earth must perform something more than one revolution before the sun appears again on the same meridian; so that the time from the sun's being on the meridian on any day, to its appearance on the same meridian the next day, is twenty-four hours.

IDES, (idus) in the Roman calendar, a denomination given to eight days in each month; commencing in the months of March, May, July, and October, on the fifteenth day, and in the other months, on the thirteenth day; and reckoned backward, so as

* The earth goes round the sun in 365 days nearly; and the ecliptic, which is the earth's path round the sun, consists of 360 degrees; hence by the rule of three, 3654 D: deg.:: 1 D: 59' 8". 2, the daily mean motion of the earth in its orbit, or the apparent mean motion of the sun in a day. Hence a clock, or chronometer, the index of which performs an exact circuit whilst the earth (or the meridian of an observer) moves over 360° 59' 8". 2 is said to be adjusted to mean solar time.

in the four months above specified to terminate on the eighth day, and in the rest on the sixth. The Ides came between the calends and the nones.

The fifteenth day, in March, May, July, and October, and the thirteenth in the other months, was called the Ides of these months; Idus Marti, Idus Maii, &c. The thirteenth day in the four months, and the eleventh in the eighth, was called the third of the Ides of such months, third Idus Martii, &c. So the twelfth day in the four, and the tenth day in the eight months, were the fourth of the Ides, fourth Idus Martii, &e. And thus of the rest, to the eighth and sixth days, which made the eighth of the Ides, eight Idus Martii, &c.

This way of accounting is still in use, in the Roman chancery, and in the calendar of the breviary. The Ides of May were consecrated to Mercury; the Ides of March were ever esteemed unhappy, after Cæsar's murder on that day; the time after the Ides of June was reckoned fortunate for those who entered into matrimony: the Ides of August were consecrated to Diana, and were observed as a feast day by the slaves. On the Ides of September auguries were taken for appointing the magistrates, who formerly entered into their offices on the Ides of May, afterwards on those of March.

CALENDS, (Calenda) in the Roman chronology, the first day of every month.

The word is formed from the Latin calo, or rather, Greek, I call, or proclaim; because, before the publication of the Roman fast, it was one of the offices of the Pontifices to watch the appearance of the new moon, and give notice to the Rex Sacrificulus; upon which a sacrifice being offered, the pontiff summoned the people together in the capital, and there with a loud voice proclaimed the number of calends, or the day whereon the nones would be; which he did by repeating this formula, as often as they were days of calends, Calo, Juno, Novella. Whence the name Calenda was given thereto, from calo calare. This is the account given by Varro.

NONES, (None) in the Roman calendar, the fifth day of the months January, February, April, June, August, September, November, and December, and the seventh of March, May, July, and October. These four last months having six days before the Nones, and the other only four.

The word apparently has its rise hence, that the day of the Nones was nine days before the Ides, and might be called Nono Idus.

March, May, July, and October, had six days in their Nones; because these alone, in the antient constitution of the year by Numa, had thirty-one days each, the rest having only twenty-nine, and February thirty. But when Cæsar reformed the year, and made other months contain thirty-one days, he did not likewise allow them six days of Nones.

An hour is the twenty-fourth part of a natural day.

Different people reckon the hours in a different manner. Babylonish hours are those which are counted from sunrising in a continued series of twenty-four. European hours are those counted from midnight, twelve from thence to noon, and from noon to midnight twelve more. Those which commence their order from noon are called astronomical, because used by astronomers.

The Jews, Chaldeans, Arabs, and other eastern people, divide their hours into a thousand and eighty scruples, eighteen whereof are equal to our minute.

SECTION IV.

OF CYCLES, EPACTS, &c.

305. A CYCLE is a circle of years, months, and days, used by chronologers, to signify a perpetual round or circulation of the same parts of time, proceeding orderly from first to last, and recurring again from last to first, successively, and without interruption.

As the annual motion of the sun, and other heavenly bodies, cannot be measured exactly without any remainder of minutes, seconds, &c. to swallow up these fractions in whole numbers, that is such as only express days and years, cycles have been invented; which, comprehending several revolutions of the same body, replace it, after a certain num