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G|Regori An CALENIDAR. 65

will be, the 21st of March. The correction introduced into the calendar by Gregory, was not adopted by the English, until the year 1752. At this time the difference between the Julian and Gregorian calendars was 11 days; it would have been 12 days, but the latter had omitted the intercalary day in the year 1700, as we have already stated. It was, therefore, enacted by Parliament, that 11 days should be left out of the month of September of the current year, by calling the day following the 2d of the month the 14th, instead of the 3d. The Greek Church have never adopted this Romish or Latin correction, and consequently, the Russians are now 12 days behind us in their reckoning, and the Christmas festival, which happens with us December 25th, occurs with them January 6th, or Epiphany day, according to our reckoning, and which is sometimes, even now, called “Old Christmas day.” The Julian and Gregorian calendars are designated by the terms “Old Style,” and “New Style.” Thus, by successive improvements, which have been almost forced upon the world, the calendar has been perfected, until it answers all the purposes of civilized life. “Time,” says Young, “is the stuff that life is made of,” and we do well, therefore, not to waste such a precious possession. We remember the inscription on the dial in the Temple, at London: “Begone about your business,” a wholesome admonition to the loiterer, and the no less appropriate device, once stamped on the old Continental coppers, a dial with the motto, “Mind your business.” There is enough to do, and time enough to do all that ought to be done. “There is a time for all things,” says Solomon, let us them, be careful and do all things in the proper time. The French Chancellor d' Aguesseau, employed all his time. Observing that Madame d' Aguesseau always delayed ten or twelve minutes before she came down to dinner, he composed a work entirely in this time, in order not to loose an instant; the result was, at the end of fifteen years, a book in three large volumes quarto, which went through several editions. No man, we venture to say, ever accomplished more, and to the better satisfaction of all interested, than Benjamin Franklin,

another economiser of time, One of his greatest discoveries was t

made in France, and that was, Sun-light was cheaper than lamplight, and better, too. A severe reprimand, from a man of his standing, and industry, upon the customs of the French court, spending the night in mirth and revelry, and sleeping all the day. It is said there is a moral in everything, to the moralizing mind. Since, then, “Time once gone, ne'er returns,” let us make the best use of it; not sad, or serious, merely, but sober and reasonable—ready to labor in the hours of labor, and to rest in the hours of rest. We shall not, then, look back on misspent moments, with that feeling so aptly expressed in the German: “Ach wie nichtig, ach wie fliichtig Ah, how vain, ah, how fleeting ! The flight of Time, which is silently, but surely and uniformly, bearing us from scenes, loved, perhaps, too well, cannot be too accurately marked. . The correction of the calendar, by Julius Caesar, has done more to perpetuate his name than the victories he won for Rome, and the name of Gregory XIII. has more of meaning in it, than that of a mere Saint, in the Romish calendar. There is something pleasing, and yet mournful, in thus minutely contemplating the passage of the year, and we would do well to imitate the good old custom which our forefathers followed, and on the first day of the New Year, make the first entry in our new

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“This shadow on the Dial’s face,

That steals from day to day
With slow, unseen, unceasing pace,

• Moments, and months, and years away,
Right onward, with resistless power,
Its stroke shall darken every hour,
Till Nature’s race be run,
And Time's last shadow shall eclipse the sun.”

J. Montgomery.

In the preceding chapter, we have made frequent use of the word day, and have throughout meant what is called a mean Solar day. We have already shown that the Siderial day is the time of an exact revolution of the earth on its axis. This day is shorter ... than the Solar day, by about 4 minutes. We have also alluded to the apparent motion of the sun in the heavens, showing that if to-day he came to the meridian at the same time with any particular star, to-morrow the star would come to the meridian before the sun, which had apparently changed its place in the heavens. Let us consider to what the difference between Solar and Siderial time is really owing, and see how much the Siderial day should be

shorter than the Solar, to do which we will have recourse to a diagram

[graphic]

...”

Let A B C D, represent the earth's annual orbit, showing the earth in four different positions, and let a be the situation of some particular meridian, that of Greenwich, for example. Now, on the supposition that the earth does not rotate on its axis at all, suppose it moving in its orbit, in the order of the letters; it is not difficult to see that the effect will be the same, as though the earth, remaining at rest in its orbit, had turned once on its axis during the year, but in a contrary direction to its present diurnal motion. Thus, while at A, the sun would be on the meridian a, but at B, one fourth of a year after, the sun would set in the east, and at C, half a year afterwards, it would be midnight at the same meridian, a. At D the sun would just begin to rise in the west, and finally at A would come to the meridian again. It will now be understood, that although the earth does turn on its axis, during its yearly circuit, yet this day as really occurs as if the earth had not the diurnal revolution, hence the number of rotations, measured by the sun’s coming to the meridian, will be less than the number as announced by a star, by one day, and therefore the Siderial day must be shorter than a Solar day, by the proportional part of a revolution, which is thus divided up among, and added to the 365 Solar days of the year. Upon the supposition that the mean Solar day is just 24 hours in length, the Siderial day will be, the one-three hundred and sixty-fifth and one-fourth, of 24 hours, shorter, i. e. 3m, 56s, very nearly, and a star, in consequence, will come to the meridian 3m, 56s, sooner than the sun, each day, or will gain so much on the sun daily.

We have more than once intimated that the time elapsed between a star’s leaving the meridian, to its return to it again, viz: 23h, 56m, 4.01s, is the precise measure of a rotation of the earth, and for this reason astronomers prefer to regulate their time keepers to show what is called Siderial time. Now, suppose to-day to be the 14th of April, which is near the time of vernal equinox, the precise point where the ecliptic intersects the equator, we will imagine to be shown by a bright star. By means of his transit instrument, the astronomer ascertains exactly when this star is on his meridian, and just then sets his clock going, the hands showing at the time Oh, Om, 0s, and at the same time the town-clock, we

Right ASCENSION AND DECLINATION. 69

will suppose, or some other time-measurer, such as a watch, or ordinary clock, is set going, showing, also, at that instant, Oh, 0m, 0s. Now the astronomer's clock is, like the other time-keepers, divided into 24 hours, only he reckons straight forward from 1 to 24 hours, while in the ordinary time-piece, the hours are numbered twice in a day, from 1 to 12. We ought to say, however, that the astronomer begins his day at noon the 14th of April, while the civil day, April 14th, began at midnight, 12 hours before, but both clocks now show Oh, Om, Qs. The astronomer's clock has a pendulum a trifle shorter than the common clock, which makes it oscillate somewhat faster, so that the gain, on the ordinary clock, may be about 3m, 56s, in a day. After an interval of 24 hours, by his clock, the astronomer again looks into the transit telescope and sees the supposed star, or equinoctial point, which is always called the first point of Aries, just on his meridian, that is, if his clock is truly adjusted, but it is not yet a day, or 24 hours, by the civil time, but lacks 3m, 56s. The next day the clocks will be still farther apart, and in about 15 days there will be 1 hour's difference, the siderial clock showing 1h, when the ordinary clock shows 12h, or noon; the latter shows the time when the sun is on the meridian, or very nearly so, but the former indicates that the first point of Aries, or the equinoctial point, crossed the meridian an hour before. Now the great convenience to the astronomer is this: As the whole heavens appear to revolve around the earth in a siderial day, he imagines a circle traced out in the heavens, which corresponds to our equator, and, commencing at the vernal equinoctial point, or first point of Aries, he divides this celestial equator, into 24 equal portions, or hours, and these he subdivides into 60 minutes, and each minute into 60 seconds, and he calls the distance of anybody from this first point of Aries, measured on the celestial equator, just as we measure longitude on a globe, or map, by ascertaining how far east or west the place is from Greenwich, measured on the terrestrial equator; this he calls the Right Ascension of that body, designated by the initials R. A., and the distance of the body north or south of the equator, he calls Declination, north or south, designated thus: N. D., or S. D., corresponding with our geographical terms, north and south D*

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