160 GULLIVER'S TRAVELS
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.
But it must be observed that this island cannot move beyond the extent of the dominions below, nor can it rise above the height of four miles. For which the astronomers (who have written large systems concerning the stone) assign the following reason: that the magnetic virtue does not extend beyond the distance of four miles, and that the mineral which acts upon the stone in the bowels of the earth, and in the sea, about six leagues distant from the shore, is not diffused through the whole globe, but terminated with the limits of the king's dominions; and it was easy, from the great advantage of such a superior situation, for a prince to bring under his obedience whatever country lay within the attraction of that magnet.
When the stone is put parallel to the plane of the horizon, the island stands still; for, in that case, the extremities of it, being at equal distance from the earth, act with equal force, the one in drawing downwards, the other in pushing upwards, and consequently no motion can ensue.
This loadstone is under the care of certain astronomers, who, from time to time, give it such positions as the monarch directs. They spend the greatest part of their lives in observing the celestial bodies, which they do by the assistance of glasses far excelling ours in goodness. For, although their largest telescopes do not exceed three feet, they magnify much more than those of a hundred yards among us, and, at the same time, shew the stars with greater clearness. This advantage hath enabled them to extend their discoveries much farther than our astronomers in Europe; for they have made a catalogue of ten thousand fixed stars, whereas the largest of ours do not contain above one-third part of that number. They have likewise discovered two lesser stars, or satellites, which revolve about