[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.

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.

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
with us, and show the stars with greater clearness. This advantage
has enabled them to extend their discoveries much further 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 Mars; whereof
the innermost is distant from the centre of the primary planet
exactly three of his diameters, and the outermost, five; the former
revolves in the space of ten hours, and the latter in twenty-one
and a half; so that the squares of their periodical times are very
near in the same proportion with the cubes of their distance from
the centre of Mars; which evidently shows them to be governed by
the same law of gravitation that influences the other heavenly
bodies.

They have observed ninety-three different comets, and settled their
periods with great exactness. If this be true (and they affirm it
with great confidence) it is much to be wished, that their
observations were made public, whereby the theory of comets, which
at present is very lame and defective, might be brought to the same
perfection with other arts of astronomy.

The king would be the most absolute prince in the universe, if he
could but prevail on a ministry to join with him; but these having
their estates below on the continent, and considering that the
office of a favourite has a very uncertain tenure, would never
consent to the enslaving of their country.

If any town should engage in rebellion or mutiny, fall into violent
factions, or refuse to pay the usual tribute, the king has two
methods of reducing them to obedience. The first and the mildest
course is, by keeping the island hovering over such a town, and the
lands about it, whereby he can deprive them of the benefit of the
sun and the rain, and consequently afflict the inhabitants with
dearth and diseases: and if the crime deserve it, they are at the
same time pelted from above with great stones, against which they
have no defence but by creeping into cellars or caves, while the
roofs of their houses are beaten to pieces. But if they still
continue obstinate, or offer to raise insurrections, he proceeds to
the last remedy, by letting the island drop directly upon their
heads, which makes a universal destruction both of houses and men.
However, this is an extremity to which the prince is seldom driven,
neither indeed is he willing to put it in execution; nor dare his
ministers advise him to an action, which, as it would render them
odious to the people, so it would be a great damage to their own
estates, which all lie below; for the island is the king's demesne.

But there is still indeed a more weighty reason, why the kings of
this country have been always averse from executing so terrible an
action, unless upon the utmost necessity. For, if the town
intended to be destroyed should have in it any tall rocks, as it
generally falls out in the larger cities, a situation probably
chosen at first with a view to prevent such a catastrophe; or if it
abound in high spires, or pillars of stone, a sudden fall might
endanger the bottom or under surface of the island, which, although
it consist, as I have said, of one entire adamant, two hundred
yards thick, might happen to crack by too great a shock, or burst
by approaching too near the fires from the houses below, as the
backs, both of iron and stone, will often do in our chimneys. Of
all this the people are well apprised, and understand how far to
carry their obstinacy, where their liberty or property is
concerned. And the king, when he is highest provoked, and most
determined to press a city to rubbish, orders the island to descend
with great gentleness, out of a pretence of tenderness to his
people, but, indeed, for fear of breaking the adamantine bottom; in
which case, it is the opinion of all their philosophers, that the
loadstone could no longer hold it up, and the whole mass would fall
to the ground.

By a fundamental law of this realm, neither the king, nor either of
his two eldest sons, are permitted to leave the island; nor the
queen, till she is past child-bearing.