To find the Sun's Place in the Ecliptic. Seek the day of the month in the calendar on the horizon, and against that day in the adjoining circle are the fign and degree in which the fun is for that day: this being done, find the fame fign and degree in the ecliptic on the surface of the globe, and this is the fun's place for that day at noon. EXAMPLES. What is the fituation of the fun at the vernal equinox? Anf. 1 deg. of Aries. Required the fun's place on the following days: the autumnal equinox, the fummer folftice, the winter folftice, Jan. 21, Feb. 28, March 28, April 16, May 12, June 19, July 14, Auguft 1, 4, 10, 25, 26, Sept. 19, Oct. 16, 25, Nov. 18, and Dec. 29. N. B. The fun's place may be more accurately found in degrees, minutes, and feconds, in the Ephemeris for the current year, under the title of the fun's longitude. * Ephemerides, in aftronomy, are tables calculated by aftronomers, fhewing the prefent ftate of the heavens for every day at noon; that is, the places wherein all the planets are found at that time. It is from thefe tables that the eclipfes, conjunctions, and aspects of the planets are determined, horofcopes, or celeftial fchemes, conftructed, &c. In England, the Nautical Almanac, or Aftronomical Ephemeris, published annually by anticipation † under the direction + Tables of this fort are fometimes made feveral years in advance. Lalande, in his Hillory of Aftronomy for 1798, mentions his having ceived the ephemerides of Bologna for twelve years, viz. from 1799 to 1810, which, he fubjoins, will ferve for the ufc of fuch as fhall make almanacs for a number of years to come. D 3 PROBLEM PROBLEM IX. The Sun's Place being given, to find the Day of the Month. This problem is only the reverfe of the preceding one; for having the fun's place given, by feeking in the calendar the correfponding day of the month, the queftion is anfwered.. EXAMPLES. What is the day of the month when the fun is in the 5th degree of Aries ?-Ans. The 25th of March. tion of Commiffioners of Longitude, is the most confiderable It began with the year 1767, and has been regularly continued ever fince. But WHITE'S Ephemeris, which was firft printed in the year 1747, is a very popular and ufeful little work, containing, befides a great variety of astronomical tables, a complete almanac, and its price unbound is only one fhilling and ninepence. Authors are greatly divided with regard to the etymology of the world Almanac; but the moft fimple derivation appears from the common fpelling, as being thought to be compofed of two Arabic ones, al manack, which fignify, the diary. Regiomontanus, a celebrated German aftronomer, is faid to have been the first perfon in Europe who reduced almanacs into their present form and method, gave the characters of each year and month, foretold the eclipfes and other phafes, calculated the motions of the planets, &c. His first almanac was published in 1474. The real name of Regio. montanus was John Muller, born at Konifberg in Franconia. He was called Regiomontanus from the Latin name of his natal place. Being called to Rome by Pope Sextus IV. to affist in correcting the calendar, he was cut off by the plague in 1476 in the 40th year of his age. What What are the days of the month in which the fun is refpectively in the firft degree of the twelve figns of the zodiac? To find the Sun's Declination, i. e. his Recefs from the Equator Northward or Southward, at any given Period, which can never exceed 23 degrees. Bring the fun's place in the ecliptic to the brazen meridian, and the degree over it is the declination fought, either North or South. N. B. The fun's declination is always North, in our fummer half year, i. e. from the 20th of March to the 23d of September, and Southward in our winter half year, from the 23d of Septem. ber to the 20th of March. Or in other words, the fun's declination is North during his courfe through the fix Northern figns, and South while he paffes through the fix Southern Signs. EXAMPLES. What is the fun's declination at the vernal and autumnal equinoxes ?—Anf. o. At the fummer and winter folftices ?-Anf. 23 deg. North, at the former; 231 deg, South, at the latter period. D 4 Required Required the fun's declination on the following days: Jan. 30, Feb. 7, 16, 25, March 14, April 12, May 29, June 24, July 21, Aug. 2, 24, Sept. 2, 3, Oct. 14, Nov. 4, 5, and Dec. 16. When the globe has a fcale of the fun's declination upon it, this problem may be folved by bringing it to the brafs meridian; for in that fituation the fun's declination is over the affigned day. N. B. The anfwers to the preceding examples may be proved by referring to the Ephemeris, under the title of the fun's declination. PROBLEM XI. To rectify the Globe for any given Place. We have before obferved *, that the elevation of the pole and the latitude of a place are convertible terms, being always equal to each other. To rectify the globe, therefore, for any propofed place, is to elevate the pole the fame number of degrees above the horizon as correfponds with its latitude; an operation which is performed by counting them upon that fide of the meridian which is numbered from the poles towards the equator, and placing the faid number of degrees in contact with the horizon. Find the latitude of the affigned place by Prob. I. EXAMPLES. Rectify the globe for London and the chief cities of Europe; for Archangel, Trebifond, Smyrna, *Art. 25. P. 23. Damafcus, Damafcus, Erzerum, Medina, Mecca, Aden, Burfa, Schiras, the Pelew Islands, Guam, Bilboa, Bourdeaux, Cape Finifterre, Oporto, Cape St. Vincent's, Fez, Cape Verd, Sierra Leona, Saldanha Bay, Mexico, Porto Bello, Quito, Truxillo, Panama, Cape Horn, Buenos Ayres, St. Sebaftian, St. Sal. vador, Paraiba, and Surinam. To rectify the Globe for any given Place and Day of the Month. Elevate the pole as directed in the laft problem; then find the fun's place for the affigned day, and bring it in contact with the meridian; fet the index to 12 on the hour circle *, and place the globe As moft, indeed we apprehend all, the hour circles on modern globes are made with two rows of figures on them, our young readers will find it abfolutely neceffary to perufe with attention the fubfequent obfervations. The 12 o'clock above mentioned will reprefent the noon of the given day, and by it any other hour may be diftinguished to be either in the morning or afternoon; for when the 12th hour is thus brought in a ftate of contact with the brazen meridian, it will appear by infpection that the hours on one of the two hour circles (on fome globes the interior, on others the exterior circle) increafe on the right hand, or Eaftern fide of the brazen meridian, and decreafe on the oppofite, or Western fide of the meridian. Now the earth's motion being, as we have before remarked, from West to Eaft, it follows of courfe, that the hours which increafe, i. e. which are numbered thus, 1, 2, 3, 4, &c. on the Eastern fide of the aforefaid 12 at noon, must be afternoon hours, their correfponding places having paffed the meridian, or period of mid-day, a proportionate fpace of time; and that the hours on the con Art. 2. page 5. trary |