Jonathan Swift: Gulliver's Travels

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

The stone cannot be removed from its place by any force, because the hoop and its feet are one continued piece with that body of adamant which constitutes the bottom of the island.

By means of this loadstone, the island is made to rise and fall, and move from one place to another. For, with respect to that part of the earth over which the monarch presides, the stone is endued at one of its sides with an attractive power, and at the other with a repulsive. Upon placing the magnet erect, with its attracting end towards the earth, the island descends; but when the repelling extremity points downwards, the island mounts directly upwards. When the position of the stone is oblique, the motion of the island is so too: for in this magnet, the forces always act in lines parallel to its direction.

By this oblique motion, the island is conveyed to different parts of the monarch's dominions. To explain the manner of its progress, let A B represent a line drawn across the dominions of Balnibarbi, let the line c d represent the loadstone, of which let d be the repelling end, and c the attracting end, the island being over C: let the stone be placed in position c d, with its repelling end downwards; then the island will be driven upwards obliquely towards D. When it is arrived at D, let the stone be turned upon its axle, till its attracting end points towards E, and then the island will be carried obliquely towards E; where, if the stone be again turned upon its axle till it stands in the position E F, with its repelling point downwards, the island will rise obliquely towards F, where, by directing the attracting end towards G, the island may be carried to G, and from G to H, by turning the stone, so as to make its repelling extremity to point directly downward. And thus, by changing the situation of the stone, as often as there is occasion, the island is made to rise and fall by turns in an oblique direction, and by those alternate risings and fallings (the obliquity being not considerable) is conveyed from one part of the dominions to the other.