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FOR THE BINDER.
The MAP of the Southern States to front the TITLE.
The MAP of the Northern States, page 33.
TABLE of Distances between the principal Towns in America
OF ASTRONOMICAL GEOGRAPHY.
COMPLETE knowledge of Geography, cannot be obtained without fome acquaintance with Aftronomy. This Compendium, therefore, will be introduced with a short account of that Science. Aftronomy treats of the heavenly bodies, and explains their motions, times, diftances and magnitudes. The regularity and beauty of thefe, and the harmonious order in which they move, fhew that their Creator and Preferver poffeffes infinite wisdom and power.
Aftronomy was first attended to by the Shepherds, on the beautiful plains of Egypt and Babylon. Their employment led them to contemplate the ftars. While their flocks, in the filence of the evening, were enjoying fweet repose, the spangled fky would naturally invite the attention of the Shepherds. The obfervation of the heavenly bodies afforded them amufement, and at the fame time affifted them in travelling in the night. A ftar guided the Shepherds to the manger where our bleffed Saviour was born. By the aid of a lively imagination, they diftributed the ftars into a number of conftellations or companies, to which they gave the names of the animals which they represented.
Of the Planets.] The fun is furrounded with seven spherical, opaque bodies, called Planets or wandering stars, which revolve about him as their centre at different distances, and in different periods, as exhibited in the following
Sun and Diameters Distance from Annual periods
Jupiter 24 94,000
y. d. h.
O 224 17
Square miles in furface.
+ 1,828,911,000,000 21,236,800 691,361,300 199,859,860 62,038,240 20,603,970,000 14,102,562,000 7,577,496,000
* From aftron, a ftar; and nomos, the law or rule.
The feven planets mentioned in the table are called primary planets; for befides thefe there are ten other bodies called fecondary planets, moons, or fatellites, which all revolve round their primaries from weft to east, and at the fame time are carried along with them round the fun, as follows:
The earth has one fatellite, viz. the moon D, which performs her revolution in 29d. 12h. 44m. at the distance of about 60 femidiameters of the earth, or 209,100 miles, and is carried with the earth round the fun once in a year.
Jupiter has four moons; Saturn has five, and is alfo encompaffed with a broad ring. The diameter of the ring is, to the diameter of Saturn, as 9 to 4, and the fpace between the body of Saturn and the ring, is equal to the breadth of the ring.
The motion of the primary planets round the fun, and alfo the motion of the fatellites round their primaries, is called their annual motion. Befides this annual motion, they revolve round their own axes from weft to eaft, and this is called their diurnal motion.
The lately difcovered planet Herfchel, was firft obferved in 1782, by that celebrated aftronomer William Herfchel, LL. D. F. R. S. In Great-Britain, it is called Georgium Sidus; but in France and America it has obtained the name of Herfchel, in honour to its learned discoverer.
Contets.] The comets are large opaque bodies, which move in very elliptical orbits and in all poffible directions. Some revolve from west to east ; fome from east to weft; others from fouth to north, or from north to fouth. Their orbits have very different inclinations to the ecliptic. Some have conjectured, that the comets were intended by the All-wife Creator, to connect fyftems, and that each of their feveral orbits includes the fun, and one of the fixed stars. The figures of the comets are very different. Some of them emit beams on all fides like hair, and are called hairy comets. Others have a long, fiery, tranfparent tail projecting from the part which is oppofite to the fun. Their magnitudes alfo are different. Some appear no bigger than ftars of the firft magnitude; others larger than the moon. They are fuppofed to be folid bodies, and very denfe; for fome of them in their nearest approach to the fun, were heated, according to Sir Ifaac Newton's calculation, 2000 times hotter than red hot iron; a degree of heat which would vitrify, or diffipate any matter known to us.
The number of comets belonging to our fyftem is not certainly known. Twenty one have been seen. Of thefe, the periods of three only have been afcertained with accuracy. One appeared in the years 1531, 1607, 1682, and 1758; its period is 75 years. Another was feen in 1532 and 1661. The third appeared laft in 1680, whofe period being 575 years, cannot be expected to return until the year 2255.
Of the Solar-System.] The feven planets, with their ten fatellites and the comets, conftitute the Solar, or as it is fometimes called, the Copernican Syftem, in honour of Copernicus, a native of Poland, who adopted the Pythagorean opinion of the heavenly bodies, and publifhed it to the world. in 1530. This is now univerfally approved as the true fyftem. It has received great improvements from Gallileo, Sir Ifaac Newton, Dr. Halley, and other philofophers in almost every age,
Of the fixed Stars.] The folar fyftem is furrounded with the fixed ftars; fo called, because they at all times preferve the fame fituation in regard to each other. Thefe ftars, when viewed with the best telescopes, appear no larger than points, which proves that they are at an immenfe diftance from us. Although their distance is not certainly known, yet it is the general opinion of aftronomers, that they are at least 100,000 times farther from us, than we are from the fun; and that our fun viewed from a fixed ftar, would appear no bigger than a ftar does to us. A found would not reach us from Sirius, or the dog-ftar, which is nearer to this earth than any of the fixed ftars, in 50,000 years. A cannon ball flying at the rate of 480 miles an hour, would not reach us in 700,000 years. Light, which is tranfmitted from one body to another almost inftantaneoufly, takes up more time in paffing from the fixed ftars to this earth, than we do in making a voyage to Europe; fo that if all the fixed ftars were now ftruck out of exiftence, they would appear to us to keep their ftations for feveral months yet to come. It is impoffible, therefore, that they fhould borrow their light from the fun, as do the planets.
The number of ftars, vifible to the naked eye at any one time, in the upper hemifphere, is not more than a thoufand. A thousand more are fupposed to be visible in the lower hemifphere; and by the help of a telefcope, a thousand more have been difcovered; fo that the whole number of ftars are reckoned at 3000. They are diftinguifhed from the planets by their twinkling.
To confider thefe ftars defigned merely to decorate the sky, and form a rich and beautiful canopy for this earth, would be derogatory to the wifdom of the Creator. Aftronomers therefore, with much reafon, have confidered the fixed ftars as fo many funs, attended with a number of revolving planets, which they illuminate, warm and cherish. If this be true, there are as many fyftems as there are fixed ftars. Thefe may alfo revolve round one common centre, forming one immenfe fyftem of fyftems. All these fyftems, we may conceive, are filled with inhabitants suited to their refpective climes; and are fo many theatres, on which the Great Creator and Governor of the Universe difplays his infinite power, wifdom and goodness, Such a view of the ftarry heavens muft fill the mind of every beholder, with fublime, magnificent, and glorious ideas of the Creator.
Of the EARTH.
[AVING taken a curfory view of the heavenly bodies, we proceed to give a more particular account of the planet which we inhabit. The Earth, though called a globe, is not perfectly round, but is widened at the equator, and flattened at the poles; fo that its diameter from eaft to weft, is about thirty miles longer than from north to fouth. Its figure is an oblate fpheroid. It moves round the fun once in a year. This is called the earth's annual motion, to which we are indebted for the difference in the length of the days and nights, and for the variety in the feafons. The diameter of the earth's orbit, is 190,346,000 miles. And fince the circumference of a circle, is to its diameter, as 355 is to 113, the circum ference of the earth's orbit is 597,987,646 miles, And as the earth de
scribes this orbit in 365 days and 6 hours, (or in 8766 hours,) it is plain that it travels at the rate of 68,217 miles every hour; fo that its velocity in its orbit is at leaft 142 times as great as the velocity of a cannon-balĺ, fuppofing the ball to move through eight miles in a minute, which it is found to do nearly. At this rate it would take 22 years and 228 days for a cannon-ball to go from this earth to the fun.
The earth is 25,038 miles in circumference; and by turning on its axis once in twenty-four hours from weft to eat, caufes a continual fucceffion of day and night, according as either fide is turned to or from the fun; and occafions an apparent motion of the fun and heavenly bodies from caft to weft. This is called the earth's diurnal, or daily motion, by which the inhabitants on the equator are carried 1040 miles every hour.
That the earth is round like a globe is evident: First, From its having been circumnavigated, or failed round by Magellan, Sir Francis Drake, Lord Anfon, Captain Cook and others. Secondly, From its fhadow in eclipfes of the moon, which fhadow is bounded by a circular line.
As the earth is round and habitable on all fides, it will doubtlefs appear ftrange, that perfons can stand directly oppofite to us on the under fide.
Magellan failed from Seville in Spain, under the auspices of Charles V. 10th of August, 1519; and having discovered the Magellanic Streights in South America, he craffed the Pacific Ocean, and arrived at the Philippine Islands where he was poisoned. His fhip returned by way of the Cape of Good Hope, 8th September 1522.
Sir Francis Drake failed from Plymouth, 13th December 1577-entered the Pacific Ocean, and fteering round America, returned November 3d, 1580. He was a man of great generofity. The booty which he took, and even the wedges of gold given him in return for his prefents to Indian chiefs, he divided in juft proportional hares with the common failors.
Thomas Cavendish failed from Plymouth, with two small ships, the 1ft of August, 1586-paffed through the Streights of Magellan-took many rich prizes along the coafts of Chili and Peru; and near California possessed himself of the St. Annan Acapulco ship, with a cargo of immenfe value. He completed the circumnavigation of the globe the gth of September, 1588.
Between the years 1598 and 1626, Oliver de Nort, of Utrecht, James Mahu, George Spillenberger, a Fleming, William Schouten, a Hollander, and James the Hermit, fucceffively failed round the globe.
Lord Anfon failed in September, 1740-doubled Cape Horn in a dangerous Jeafon-loft most of his men by the fcurvy, and with only one remaining fhip, the Centurion, craffed the Great Pacific Ocean, which is 10,000 miles over—took a Spanish galleon, on her paffage from Acapulco to Manilla, and returned home in June 1744.
Byron-Bouganville, a Frenchman-Wallis and Carteret, successively circumnavigated the globe, between the years 1764 and 1769.
Captain Cook, in the hip Endeavour, failed from Plymouth the 26th of Auguft, 1768, and after a most fatisfactory voyage, returned the 12th of June, 1771. He fet out on a fecond voyage the 14th of February, 1776—made many important difcoveries, and was killed on the island of Owyhee by the natives, he 14th of February, 1779. His hips under the command of Captain Clerk, returned the 16th of October, 1780.