Jonathan Swift: Gulliver's Travels

PART III. A VOYAGE TO LAPUTA, BALNIBARBI, LUGGNAGG, GLUBBDUBDRIB, AND JAPAN. 3. CHAPTER III.

[A phenomenon solved by modern philosophy and astronomy. The Laputians' great improvements in the latter. The king's method of suppressing insurrections.]

I desired leave of this prince to see the curiosities of the island, which he was graciously pleased to grant, and ordered my tutor to attend me. I chiefly wanted to know, to what cause, in art or in nature, it owed its several motions, whereof I will now give a philosophical account to the reader.

The flying or floating island is exactly circular, its diameter 7837 yards, or about four miles and a half, and consequently contains ten thousand acres. It is three hundred yards thick. The bottom, or under surface, which appears to those who view it below, is one even regular plate of adamant, shooting up to the height of about two hundred yards. Above it lie the several minerals in their usual order, and over all is a coat of rich mould, ten or twelve feet deep. The declivity of the upper surface, from the circumference to the centre, is the natural cause why all the dews and rains, which fall upon the island, are conveyed in small rivulets toward the middle, where they are emptied into four large basins, each of about half a mile in circuit, and two hundred yards distant from the centre. From these basins the water is continually exhaled by the sun in the daytime, which effectually prevents their overflowing. Besides, as it is in the power of the monarch to raise the island above the region of clouds and vapours, he can prevent the falling of dews and rain whenever he pleases. For the highest clouds cannot rise above two miles, as naturalists agree, at least they were never known to do so in that country.

At the centre of the island there is a chasm about fifty yards in diameter, whence the astronomers descend into a large dome, which is therefore called flandona gagnole, or the astronomer's cave, situated at the depth of a hundred yards beneath the upper surface of the adamant. In this cave are twenty lamps continually burning, which, from the reflection of the adamant, cast a strong light into every part. The place is stored with great variety of sextants, quadrants, telescopes, astrolabes, and other astronomical instruments. But the greatest curiosity, upon which the fate of the island depends, is a loadstone of a prodigious size, in shape resembling a weaver's shuttle. It is in length six yards, and in the thickest part at least three yards over. This magnet is sustained by a very strong axle of adamant passing through its middle, upon which it plays, and is poised so exactly that the weakest hand can turn it. It is hooped round with a hollow cylinder of adamant, four feet yards in diameter, placed horizontally, and supported by eight adamantine feet, each six yards high. In the middle of the concave side, there is a groove twelve inches deep, in which the extremities of the axle are lodged, and turned round as there is occasion.