The transitions of light and darkness, whence proceed the alternations of day and night, are produced by this diurnal revolution successively presenting the different parts of the earth to the rays of the sun.  The latter is, according to the best, that is to say, the latest, accounts a luminous or fiery body, of a prodigious magnitude, from which this world is driven by a centrifugal or repelling power, and to which it is drawn by a centripetal or attractive force; otherwise called the attraction of gravitation; the combination, or rather the counteraction, of these two opposing impulses producing a circular and annual revolution.  Hence result the different seasons of the year—­viz., spring, summer, autumn, and winter.

This I believe to be the most approved modern theory on the subject; though there be many philosophers who have entertained very different opinions; some, too, of them entitled to much deference from their great antiquity and illustrious characters.  Thus it was advanced by some of the ancient sages that the earth was an extended plain, supported by vast pillars; and by others that it rested on the head of a snake, or the back of a huge tortoise; but as they did not provide a resting place for either the pillars or the tortoise, the whole theory fell to the ground for want of proper foundation.

The Brahmins assert, that the heavens rest upon the earth, and the sun and moon swim therein like fishes in the water, moving from east to west by day, and gliding along the edge of the horizon to their original stations during the night;[2] while, according to the Pauranicas of India, it is a vast plain, encircled by seven oceans of mild, nectar, and other delicious liquids; that it is studded with seven mountains, and ornamented in the center by a mountainous rock of burnished gold; and that a great dragon occasionally swallows up the moon, which accounts for the phenomena of lunar eclipses.[3]

Beside these, and many other equally sage opinions, we have the profound conjectures of Aboul-Hassan-Aly, son of Al Khan, son of Aly, son of Abderrahman, son of Abdallah, son of Masoud el-Hadheli, who is commonly called Masoudi, and surnamed Cothbeddin, but who takes the humble title of Laheb-ar-rasoul, which means the companion of the ambassador of God.  He has written a universal history, entitled, “Mouroudge-ed-dharab or the Golden Meadows, and the Mines of Precious Stones."[4] In this valuable work he has related the history of the world, from the creation down to the moment of writing; which was under the Khaliphat of Mothi Billah, in the month Dgioumadi-el-aoual of the 336th year of the Hegira or flight of the Prophet.  He informs us that the earth is a huge bird, Mecca and Medina constitute the head, Persia and India the right wing, the land of Gog the left wing, and Africa the tail.  He informs us moreover, that an earth has existed before the present (which he considers as a mere chicken of 7,000 years), that it has undergone divers deluges, and that, according to the opinion of some well-informed Brahmins of his acquaintance; it will be renovated every seventy thousandth hazarouam; each hazarouam consisting of 12,000 years.