And in Saturn. If you make the Hole twice as little in breadth, you will ſee the ſame in Saturn. And altho’ his Light be but the hundredth part of ours, yet you ſee it makes him ſhine tolerably bright in a dark Night. But in both theſe Planets, if there ever be any cloudy Days, it muſt be very dark in compariſon of us; yet without doubt the Inhabitants have no more reaſon to complain of the want of Light, than our Owls and Batts, to whom the Twilight or the Night itſelf is more agreeable than the Brightneſs of the Day.
In Jupiter their days are five Hours. But it’s a little ſtrange, that when Jupiter is ſo much bigger than our Planet, their Days and Nights ſhould be but five of our Hours. By this we may ſee that Nature has not obſerv’d that proportion that their Bulk ſeems to require, ſeeing in Mars the Days are very little different from ours. But in the length of their Years, that is, in the Revolution of the Planets round the Sun, there is an exact proportion to [[121]]their diſtances from the Sun followed. For as the Cubes of their Diſtances, ſo are the Squares of their Revolutions, as Kepler firſt ſound out. Which proportion the Moons of Jupiter and Saturn keep in their Courſes round thoſe Always of the ſame length. Planets. As the Years and Days in Jupiter are different from ours in this reſpect, ſo are the Days in another; namely, that they are all of the ſame length. For they there enjoy a perpetual Equinox, their Axis having little or no inclination to their Orbit, as the Earth’s has, as has been diſcovered by Teleſcopes. The Countries that lie near their Poles have little or no Heat, by reaſon the Rays of the Sun fall ſo obliquely upon them; but then they are freed from the Inconveniency that ours are troubled with, of tedious long half-year Nights, and have the conſtant returns of Day and Night every five Hours. Indeed ſuch ſhort Days would not be agreeable to us, but we think our ſelves much better done by, that ours are more than twice as long, tho’ upon no other account, but that whatever is our own, we are apt to imagine, muſt be beſt. [[122]]
The reſt of the Planets are ſo near the Sun (Mars himſelf never being above 18 degrees from it) that in Jupiter they have the ſight only of Saturn. But we cannot deny but that their four Moons ſtand them in greater ſtead than our one doth us, if ’twere only that they ſeldom know any ſuch Thing as to be without Moonſhiny Nights. And they are of great Advantage to them, as we ſaid before, in their Navigation, if they have any ſuch thing. Not to mention the pleaſant Sights of their frequent Conjunctions and Eclipſes, Things that they are ſeldom a Day without.
Saturn enjoys all thoſe Pleaſures and Advantages in a ſtill higher Degree, as well for his five Moons, as for the delightful Proſpect that the Ring about him affords his Inhabitants Night and Day. But we will give an account of their Aſtronomy, as we have done of the reſt of the Planets.
They ſee the fix’d Stars juſt as we do. And firſt of all we ſhall obſerve what we might have remark’d before, but which will be more ſtrange here, that the fix’d Stars appear to them of [[123]]the ſame Figure and Magnitude, and with the ſame degree of Light that they do to us: and this, by reaſon of their immenſe diſtance, of which we ſhall have occaſion to ſpeak by and by. In compariſon with which the Space that a Bullet-ſhot out of a Cannon could travel in 25 Years, would be almoſt nothing.
Their Aſtronomers have all the ſame Signs of the Bear, the Lion, Orion, and the reſt, but not turning upon the ſame Axis with us: for that’s different in all the Planets.
As Jupiter can ſee no Planet but Saturn, ſo Saturn knows of no Planet but Jupiter; which appears to him much as Venus doth to us, never removing above 37 Degrees from the Sun. The Length of their Days I cannot determine: But if from the Diſtance and Period of his innermoſt Attendant, and comparing it with the innermoſt of Jupiter’s, a Man may venture to give a Gueſs, they are very little different from Jupiter’s, 10 Hours or ſomewhat leſs. But whereas in Jupiter theſe are equally divided between [[124]]Light and Darkneſs, the Inhabitants of Saturn muſt perceive a more ſenſible difference than we, eſpecially between Summer and Winter. For our Axis inclines to the Plane of the Ecliptick but 23 degrees and a half, but there’s above 31. Upon this Account his Moons muſt decline very much from the Path that the Sun ſeems to move in, and his Inhabitants can never have a full Moon but juſt at the Equinoxes; Two of which fall out in 30 of our Years. ’Tis this Poſition of the Axis too that is the Cauſe of thoſe delightful Appearances, and wonderful Proſpects that its Inhabitants enjoy: For the better underſtanding of which I ſhall draw a Figure of Saturn with his Ring about him: in which the Proportion between the Diameters of the Globe and Ring is as 9 to 4. And the empty Space between them is of the ſame Breadth with the Ring itſelf. All Obſervations conſpire to prove that That is of no great Thickneſs, altho’ if we ſhould allow it ſix hundred German Miles, I think, conſidering its Diameter, we ſhould not overdo the Matter.
Fig. 4.
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