The Civil Year is the same with the Political established with the laws of a country; and is either moveable or immoveable. The moveable year consists of 365 days, being less than the tropical year by almost six hours, and is called the Egyptian Year, because observed in that Country.

The Romans divided the year into 12 kalendar months, to which they gave particular names, and are still retained by most of the European nations, viz. January, February, March, April, May, June, July, August, September, October, November, and December. The number of days in each month may be known by the following verses:

The year is also divided into four quarters or seasons, viz. Spring, Summer, Autumn, and Winter. These quarters are properly made when the Sun enters into the equinoctial and solstitial points of the ecliptic; but in civil uses they are differently reckoned, according to the customs of several countries. In England, we commonly reckon the first day of January to be the first in the year, which is therefore vulgarly called New-Year’s-Day; but in political and ecclesiastical affairs, the year is reckoned to commence on Lady-day which is the 25th of March; and from thence to Midsummer-day, which is the 24th of June, is reckoned the first quarter; from Midsummer-day to Michaelmas-day, which is the 29th of September, is the second quarter; the third quarter is reckoned from Michaelmas-day to Christmas-day, which is the 25th of December; and from Christmas-day to Lady-day, is reckoned the last quarter in the year. In common affairs, a quarter is reckoned from a certain day to the same in the fourth month following. Sometimes a month is reckoned four weeks, or 28 days, and so a quarter 12 weeks. To all the inhabitants in the (Northern/Southern) Hemisphere, their Midsummer is properly when the Sun is in the tropic of (Cancer,/Capricorn,) and their Midwinter at the opposite time of the year; but those who live under the equinoctial have two winters, &c. when the Sun is in either tropic; tho’ indeed properly, there is no season that may be called winter in those parts of the world.

The Egyptian year of 365 days being less than the true solar year, by almost six hours, it follows, that four such years are less than four solar years by a whole day; and therefore in 365 times four years, that is, in 1460 years, the beginning of the years move through all the seasons. To remedy this inconveniency, Julius Cæsar (considering that the six hours, which remain at the end of every year, will in four years make a natural day) ordered that every fourth year should have an intercalary day, which therefore consists of 366 days; the day added was put in the month of February, by postponing St. Matthias’s day, which in common years fall on the 24th, to the 25th of the said month, all the fixed feasts in the year from thenceforwards falling a week-day later than otherwise they would. According to the Roman way of reckoning, the 24th of February was the sixth of the kalends of March, and it was ordered that for this year there should be two sixths, or that the sixth of the kalends of March should be twice repeated; upon which account the year was called Bissextile, which we now call the Leap-Year.

To find whether the year of our Lord be leap-year, or the first, second, or third after; divide it by four, and the remainder, if there be any, shews how many years it is after leap-year; but if there be no remainder, then that year is leap-year: Or, you may omit the hundreds and scores, and divide the residue by 4, Examp. 1757, omitting the hundreds and the twenties, I divide the residue 17, by 4, and the remainder 1, shews it to be the first after leap-year.

This method of reckoning the year, viz. making the common year to consist of 365 days, and every fourth year to have 366 days, is now used in Great-Britain and Ireland, and some of the Northern parts of Europe, and is called the Julian Account, or the Old Style. But the time appointed by Julius Cæsar for the length of a solar year is too much; for the Sun finishes his course in the ecliptic, in 365 days, 5 hours, and 49 minutes, which is 11 minutes less than the civil year; and therefore he again begins his circuit 11 minutes before the civil year is ended; and so much being gained every year, amounts in 131 years, to a whole day. So that if the Sun in any year entered the equinox upon the 20th of March at noon, after the space of 131 years, he’ll enter the same point on the same hour, on the 19th of March. And therefore the exquinoxes will not always fall on the same day of the month, but by degrees will move towards the beginning of the year.

At the time of the Council of Nice, when the terms were settled for observing of Easter, the Vernal Equinox fell upon the 21st of March; but by its falling backwards 11 minutes every year, it was found that in Anno 1582, when the kalendar was corrected, the Sun entered the equinoctial circle on the 11th of March, having departed ten whole days from its former place in the year: and therefore Pope Gregory the XIIIth, designing to place the equinoxes in their situation with respect to the year, took these ten days out of the kalendar, and ordered that the 11th of March should be reckoned as the twenty-first: And to prevent the seasons of the year from going backwards for the future, he ordered every hundredth year, which in Julian form was to be a Bissextile, should be a common year, and consist only of 365 days; but that being too much, every fourth hundred was to remain Bissextile. This form of reckoning being established by the authority of Pope Gregory XIII. is called the Gregorian Account, or the New Style; and is observed in all the countries where the authority of the Pope is acknowledged, and likewise by several nations of the reformed religion. There being now above an hundred years past, since the reformation was made in the kalendar, the Gregorian account has accordingly got before the Julian one day more than it was in the time of its institution, the difference between these two accounts being now eleven days; so that the first day of any month, according to that way of reckoning, is the 12th of the same month, according to the New Style.

I shall conclude this section with a brief account of the Atmosphere.

The Atmosphere is that thin body of air which surrounds the Earth, in which the clouds hover, and by which in their descent they are broke into drops of rain; which sometimes, according to the warmth or coldness of air, are froze into Snow, or Hailstones. Thunder and Lightning are also made in the Atmosphere, and wind is nothing else but a percussion of the air, occasioned by its different density in different places. The benefits we receive from the atmosphere are innumerable; without air no earthly creature could live, as is plainly proved by experiments made by the Air-Pump; and the wholsomeness of a climate chiefly depends upon that of its air: If there was no atmosphere to reflect the rays of the Sun, no part of the heavens would be lucid and bright, but that wherein the Sun was placed; and if a spectator should turn his back towards the Sun, he would immediately perceive it to be quite dark, and the least Stars would be seen shining as they do in the clearest night; and the Sun immediately before his setting would shine as brisk as at noon, but in a moment, as soon as he got below the horizon, the whole hemisphere of the Earth would be involved in as great a darkness as if it were midnight.

But by means of the atmosphere it happens, that while the Sun is above the horizon, the whole face of the heavens is strongly illuminated by its rays, so as to obscure the faint light of the Stars, and render them invisible; and after Sun-setting, though we receive no direct light from him, yet we enjoy its reflected light for some time: For the atmosphere being higher than we are, is a longer time before it is withdrawn from the Sun (as if a man was to run to the top of a steeple, he might see the Sun after it had been set to those at the bottom.) The rays which the atmosphere receives from the Sun, after he is withdrawn from our sight, are by refraction faintly transmitted to us; until the Sun having got about 18 degrees below the horizon, he no longer enlightens our atmosphere, and then all that part thereof which is over us becomes dark. After the same manner in the morning, when the Sun comes within 18 degrees of our horizon, he again begins to enlighten the atmosphere, and so more and more by degrees, until he rises and makes full day.

This small illumination of the atmosphere, and the state of the Heavens between day and night, is called the Twilight, or the Crepusculum.

The duration of twilight is different in different climates, and in the same place at different times of the year. The beginning or ending of twilight being accurately given, we may from thence easily find the height of the atmosphere, which is not always the same. The mean height of the atmosphere is computed to be about 40 miles; but it is probable, the air may extend itself a great deal further, there being properly no other limits to it, as we can conceive, but as it continually decreases in density the farther remote it is from the Earth, in a certain ratio; which at last, as to our conception, must in a manner terminate.