[Her airless realms of frost. l. 82. If the moon had no atmosphere at the time of its elevation from the earth; or if its atmosphere was afterwards stolen from it by the earth's attraction; the water on the moon would rise quickly into vapour; and the cold produced by a certain quantity of this evaporation would congeal the remainder of it. Hence it is not probable that the moon is at present inhabited, but as it seems to have suffered and to continue to suffer much by volcanos, a sufficient quantity of air may in process of time be generated to produce an atmosphere; which may prevent its heat from so easily escaping, and its water from so easily evaporating, and thence become fit for the production of vegetables and animals.
That the moon possesses little or no atmosphere is deduced from the undiminished lustre of the stars, at the instant when they emerge from behind her disk. That the ocean of the moon is frozen, is confirmed from there being no appearance of lunar tides; which, if they existed, would cover the part of her disk nearest the earth. See note on Canto III. l. 61.]
"GNOMES! how you trembled! with the dreadful force
When Earth recoiling stagger'd from her course;
85 When, as her Line in slower circles spun,
And her shock'd axis nodded from the sun,
With dreadful march the accumulated main
Swept her vast wrecks of mountain, vale, and plain;
And, while new tides their shouting floods unite,
90 And hail their Queen, fair Regent of the night;
Chain'd to one centre whirl'd the kindred spheres,
And mark'd with lunar cycles solar years.
[When earth recoiling. l. 84. On supposition that the moon was thrown from the earth by the explosion of water or the generation of other vapours of greater power, the remaining part of the globe would recede from its orbit in one direction as the moon receded in another, and that in proportion to the respective momentum of each, and would afterwards revolve round their common centre of gravity.
If the moon rose from any part of the earth except exactly at the line or poles, the shock would tend to turn the axis of the earth out of its previous direction. And as a mass of matter rising from deep parts of the globe would have previously acquired less diurnal velocity than the earth's surface from whence it rose, it would receive during the time of its rising additional velocity from the earth's surface, and would consequently so much retard the motion of the earth round its axis.
When the earth thus receded the shock would overturn all its buildings and forests, and the water would rush with inconceivable violence over its surface towards the new satellite, from two causes, both by its not at first acquiring the velocity with which the earth receded, and by the attraction of the new moon, as it leaves the earth; on these accounts at first there would be but one tide till the moon receded to a greater distance, and the earth moving round a common centre of gravity between them, the water on the side furthest from the moon would acquire a centrifugal force in respect to this common centre between itself and the moon.]
IV. "GNOMES! you then bade dissolving SHELLS distil
From the loose summits of each shatter'd hill,
95 To each fine pore and dark interstice flow,
And fill with liquid chalk the mass below.
Whence sparry forms in dusky caverns gleam
With borrow'd light, and twice refract the beam;
While in white beds congealing rocks beneath
100 Court the nice chissel, and desire to breathe.—
[Footnote: Dissolving shells distil. l. 93. The lime-stone rocks have had their origin from shells formed beneath the sea, the softer strata gradually dissolving and filling up the interstices of the harder ones, afterwards when these accumulations of shells were elevated above the waters the upper strata became dissolved by the actions of the air and dews, and filled up the interstices beneath, producing solid rocks of different kinds from the coarse lime-stones to the finest marbles. When those lime-stones have been in such a situation that they could form perfect crystals they are called spars, some of which possess a double refraction, as observed by Sir Isaac Newton. When these crystals are jumbled together or mixed with some colouring impurities it is termed marble, if its texture be equable and firm; if its texture be coarse and porous yet hard, it is called lime-stone; if its texture be very loose and porous it is termed chalk. In some rocks the shells remain almost unchanged and only covered, or bedded with lime-stone, which seems to have been dissolved and sunk down amongst them. In others the softer shells and bones are dissolved, and only sharks teeth or harder echini have preserved their form inveloped in the chalk or lime-stone; in some marbles the solution has been compleat and no vestiges of shell appear, as in the white kind called statuary by the workmen. See addit. notes, No. XVI.]
"Hence wearied HERCULES in marble rears
His languid limbs, and rests a thousand years;
Still, as he leans, shall young ANTINOUS please
With careless grace, and unaffected ease;
105 Onward with loftier step APOLLO spring,
And launch the unerring arrow from the string;
In Beauty's bashful form, the veil unfurl'd,
Ideal VENUS win the gazing world.
Hence on ROUBILIAC'S tomb shall Fame sublime
110 Wave her triumphant wings, and conquer Time;
Long with soft touch shall DAMER'S chissel charm,
With grace delight us, and with beauty warm;
FOSTER'S fine form shall hearts unborn engage,
And MELBOURN's smile enchant another age.
[Hence wearied Hercules. l. 101. Alluding to the celebrated Hercules of Glyco resting after his labours; and to the easy attitude of Antinous; the lofty step of the Apollo of Belvidere; and the retreating modesty of the Venus de Medici. Many of the designs by Roubiliac in Westminster Abbey are uncommonly poetical; the allegory of Time and Fame contending for the trophy of General Wade, which is here alluded to, is beautifully told; the wings of Fame are still expanded, and her hair still floating in the air; which not only shews that she has that moment arrived, but also that her force is not yet expended; at the same time, that the old figure of Time with his disordered wings is rather leaning backwards and yielding to her impulse, and must apparently in another instant be driven from his attack upon the trophy.]