תמונות בעמוד
PDF
[ocr errors][ocr errors][ocr errors]

COMPLETE knowledge of Geography, cannot be obtained without

A some acquaintance with Astronomy. 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 possesses infinite wisdom and power.

Astronomy was first attended to by the Shepherds, on the beautiful plains of Egypt and Babylon. Their employment led them 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 observation of the heavenly bodies afforded them amusement, and at the same time affifted them in travelling in the night. A star 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

[merged small][ocr errors][ocr errors]
[merged small][ocr errors]

The seven planets mentioned in the table are called primary planets ; for besites these there are ten other bodies called secondary planets, moons, or satellites, which all revolve round their primaries from west to east, and at the same time are carried along with them round the sun, 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 earth round the sun 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 Great-Britain, it is called Georgium Sidus ; but in France and America it has obtained the name of Herschel, in honour to its learned discoverer.

[ocr errors][ocr errors][ocr errors][ocr errors][merged small][ocr errors]
« הקודםהמשך »