« הקודםהמשך »
ibid. 424, 425
427 432 434 435 440
Rivers, Mountains, Soil, Climate, &c.
BRITISH AMERICAN DOMINIONS.
473 474 475
494 495 497
498 500 562
The MAP of the Southern States to front the TITLE.
TABLE of Distances between the principal Towns in America
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.
Astronomy * treats of the heavenly bodies, and explains their motions, times, distances and magnitudes. The regularity and beauty of these, and the harmonious order in which they move, shew that their Creator and Preserver pofTefles intinite wisdom and power.
Astronomy was first attended to by the Shepherds, on the beautiful plains of Egypt and Babylon. Their employment led thein to contemplate the stars. While their flocks, in the filence of the evening, were enjoying sweet repose, the spangled sky would naturally invite the attention of the Shepherds. The obfervation of the heavenly bodies afforded them amusement, and at the same time aslifted them in travelling in the night. A ftar guided the Shepherds to the manger where our blessed Saviour was born. By the aid of a lively imagination, they distributed the stars into a number of constellations or companies, to which they gave the names of the animals which they represented.
Of the Planets.] The sun is surrounded 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
Diameters Distance from Annual periods in Eng.miles
round the Sun.
Square miles in
d, h. 1,828,911,000,000 36,841,468
21,236,800 9,330 68,891,486 O224 17 691,361,300 7,970 95,173,000
199,859,860 5,400 145,014,148 I 321 17 62,038,240 94,000 494,990,976 11 314 18 20,603,970,000 78,000 907,956,130 29 174 o 14,102,562,000 36,000 1800,000,000 82 34
* From astron, a sar; and nomos, the law or rule.
The seven planets mentioned in the table are called primary planets ; for besides these there are ten other bodies called secondary planets, moons, or satellites, which all revolve round their primaries from west to eat, and at the same time are carried along with them round the fun, as follows:
The earth has one satellite, viz. the moon ), which performs her revolution in 29d. 12h. 44m. at the distance of about 60 semidiameters of the earth, or 209,100 miles, and is carried with the carth round the fun once in a year.
Jupiter has four moons ; Saturn has five, and is also encompassed with a broad ring. The diameter of the ring is to the diameter of Saturn, as 9 to 4, and the space between the body of Saturn and the ring, is equal to the breadth of the ring.
The motion of the primary planets round the sun, and also the motion of the satellites round their primaries, are called their annual motions. Befides this annual motion, they revolve 'round their own axes from west to east, and this is called their diurnal motion.
The lately discovered planet Herschel, was first observed in 1782, by that celebrated astronomer William Herschel, LL.D. F. R. S. In Greai-Britain, it is called Georgium Sidus ; but in France and America it has obtained the name of Herschel, in honour to its learned discoverer.
Comets.] The comets are large opaque bodies, which move in very elliptical orbits, and in all possible directions. Some revolve from west to east ; some from east to weft; others from south to north; or from north to south. Their orbits have very different inclinations to the ecliptic. Some have conjectured, that the comets were intended by the All-wise Creator, to connect systems, and that each of their several orbits includes the sun, and one of the fixed stars. The figures of the comets are very different. Some of them emit beams on all sides like hair, and are called hairy comets. Others have a long, fiery, transparent tail, projecting from the part which is opposite to the sun.
Their magnitudes also are different. Some appear no bigger than stars of the first magnitude ; others larger than the moon. They are supposed to be folid bodies, and very dense ; for some of them in their nearest approach to the sun, were heated, according to Sir Isaac Newton's calculation, 2000 times hotter than red hot iron ; a degree of heat which would vitrify, or dissipate any matter known to us.
The number of comets belonging to our system is not certainly known. Twenty-one have been seen. Of these, 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 seen in 1532 and 1661. The third appeared last in 1680, whose period being 575 years, cannot be expected to return until the year 2255.
Of the Solar-System.] The seven planets, with their ten satellites and the comets, constitute the Solar, or as it is sometimes called, the Copernican System, in honour of Copernicus, a native of Poland, who adopted the Pythagorean opinion of the heavenly bodies, and published it to the world in 1530. This is now universally approved as the true system. It has received great improvements from Gallileo, Sir Ifaac Newton, Dr. Halley, and other philosophers in almoit every’age.