[A phenomenon solved by modern philosophy and astronomy. The Laputians' grea_mprovements in the latter. The king's method of suppressing insurrections.]
I desired leave of this prince to see the curiosities of the island, which h_as graciously pleased to grant, and ordered my tutor to attend me. I chiefl_anted to know, to what cause, in art or in nature, it owed its severa_otions, whereof I will now give a philosophical account to the reader.
The flying or floating island is exactly circular, its diameter 7837 yards, o_bout four miles and a half, and consequently contains ten thousand acres. I_s three hundred yards thick. The bottom, or under surface, which appears t_hose who view it below, is one even regular plate of adamant, shooting up t_he height of about two hundred yards. Above it lie the several minerals i_heir usual order, and over all is a coat of rich mould, ten or twelve fee_eep. The declivity of the upper surface, from the circumference to th_entre, is the natural cause why all the dews and rains, which fall upon th_sland, are conveyed in small rivulets toward the middle, where they ar_mptied into four large basins, each of about half a mile in circuit, and tw_undred yards distant from the centre. From these basins the water i_ontinually exhaled by the sun in the daytime, which effectually prevent_heir overflowing. Besides, as it is in the power of the monarch to raise th_sland above the region of clouds and vapours, he can prevent the falling o_ews and rain whenever he pleases. For the highest clouds cannot rise abov_wo miles, as naturalists agree, at least they were never known to do so i_hat 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 calle_LANDONA GAGNOLE, or the astronomer's cave, situated at the depth of a hundre_ards beneath the upper surface of the adamant. In this cave are twenty lamp_ontinually burning, which, from the reflection of the adamant, cast a stron_ight into every part. The place is stored with great variety of sextants,
quadrants, telescopes, astrolabes, and other astronomical instruments. But th_reatest curiosity, upon which the fate of the island depends, is a loadston_f a prodigious size, in shape resembling a weaver's shuttle. It is in lengt_ix yards, and in the thickest part at least three yards over. This magnet i_ustained by a very strong axle of adamant passing through its middle, upo_hich it plays, and is poised so exactly that the weakest hand can turn it. I_s hooped round with a hollow cylinder of adamant, four feet yards i_iameter, placed horizontally, and supported by eight adamantine feet, eac_ix yards high. In the middle of the concave side, there is a groove twelv_nches deep, in which the extremities of the axle are lodged, and turned roun_s there is occasion.
The stone cannot be removed from its place by any force, because the hoop an_ts feet are one continued piece with that body of adamant which constitute_he bottom of the island.
By means of this loadstone, the island is made to rise and fall, and move fro_ne place to another. For, with respect to that part of the earth over whic_he monarch presides, the stone is endued at one of its sides with a_ttractive power, and at the other with a repulsive. Upon placing the magne_rect, with its attracting end towards the earth, the island descends; bu_hen the repelling extremity points downwards, the island mounts directl_pwards. When the position of the stone is oblique, the motion of the islan_s so too: for in this magnet, the forces always act in lines parallel to it_irection.
By this oblique motion, the island is conveyed to different parts of th_onarch's dominions. To explain the manner of its progress, let A B represen_ line drawn across the dominions of Balnibarbi, let the line C D represen_he 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 it_epelling end downwards; then the island will be driven upwards obliquel_owards 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 carrie_bliquely towards E; where, if the stone be again turned upon its axle till i_tands in the position E F, with its repelling point downwards, the islan_ill rise obliquely towards F, where, by directing the attracting end toward_, the island may be carried to G, and from G to H, by turning the stone, s_s to make its repelling extremity to point directly downward. And thus, b_hanging the situation of the stone, as often as there is occasion, the islan_s made to rise and fall by turns in an oblique direction, and by thos_lternate risings and fallings (the obliquity being not considerable) i_onveyed from one part of the dominions to the other.
But it must be observed, that this island cannot move beyond the extent of th_ominions below, nor can it rise above the height of four miles. For which th_stronomers (who have written large systems concerning the stone) assign th_ollowing reason: that the magnetic virtue does not extend beyond the distanc_f four miles, and that the mineral, which acts upon the stone in the bowel_f the earth, and in the sea about six leagues distant from the shore, is no_iffused through the whole globe, but terminated with the limits of the king'_ominions; and it was easy, from the great advantage of such a superio_ituation, for a prince to bring under his obedience whatever country la_ithin the attraction of that magnet.
When the stone is put parallel to the plane of the horizon, the island stand_till; for in that case the extremities of it, being at equal distance fro_he earth, act with equal force, the one in drawing downwards, the other i_ushing upwards, and consequently no motion can ensue.
This loadstone is under the care of certain astronomers, who, from time t_ime, 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 magnif_uch more than those of a hundred with us, and show the stars with greate_learness. This advantage has enabled them to extend their discoveries muc_urther than our astronomers in Europe; for they have made a catalogue of te_housand fixed stars, whereas the largest of ours do not contain above on_hird part of that number. They have likewise discovered two lesser stars, o_atellites, which revolve about Mars; whereof the innermost is distant fro_he centre of the primary planet exactly three of his diameters, and th_utermost, five; the former revolves in the space of ten hours, and the latte_n twenty-one and a half; so that the squares of their periodical times ar_ery near in the same proportion with the cubes of their distance from th_entre of Mars; which evidently shows them to be governed by the same law o_ravitation that influences the other heavenly bodies.
They have observed ninety-three different comets, and settled their period_ith great exactness. If this be true (and they affirm it with grea_onfidence) 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 bu_revail on a ministry to join with him; but these having their estates belo_n the continent, and considering that the office of a favourite has a ver_ncertain 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 the_o obedience. The first and the mildest course is, by keeping the islan_overing over such a town, and the lands about it, whereby he can deprive the_f the benefit of the sun and the rain, and consequently afflict th_nhabitants with dearth and diseases: and if the crime deserve it, they are a_he same time pelted from above with great stones, against which they have n_efence but by creeping into cellars or caves, while the roofs of their house_re beaten to pieces. But if they still continue obstinate, or offer to rais_nsurrections, he proceeds to the last remedy, by letting the island dro_irectly upon their heads, which makes a universal destruction both of house_nd 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 minister_dvise 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; fo_he island is the king's demesne.
But there is still indeed a more weighty reason, why the kings of this countr_ave been always averse from executing so terrible an action, unless upon th_tmost necessity. For, if the town intended to be destroyed should have in i_ny tall rocks, as it generally falls out in the larger cities, a situatio_robably chosen at first with a view to prevent such a catastrophe; or if i_bound in high spires, or pillars of stone, a sudden fall might endanger th_ottom or under surface of the island, which, although it consist, as I hav_aid, of one entire adamant, two hundred yards thick, might happen to crack b_oo great a shock, or burst by approaching too near the fires from the house_elow, as the backs, both of iron and stone, will often do in our chimneys. O_ll this the people are well apprised, and understand how far to carry thei_bstinacy, where their liberty or property is concerned. And the king, when h_s highest provoked, and most determined to press a city to rubbish, order_he island to descend with great gentleness, out of a pretence of tendernes_o his people, but, indeed, for fear of breaking the adamantine bottom; i_hich case, it is the opinion of all their philosophers, that the loadston_ould 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 tw_ldest sons, are permitted to leave the island; nor the queen, till she i_ast child-bearing.