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tence, importing, that he had viewed Saturn with three Bodies; meaning the Body of Saturn itself in the Middle, and the oval Anfa, or Ends of Saturn's Ring, which appeared, at firft Sight, like two other Globes, though imperfectly; and, indeed, it was two whole Years before he was convinced that Saturn was not a triple Body. However, by frequently viewing of him, he obferved, with many others, that it was nothing more than a large Ring, encompaffing the Body.

Euphrof. If this Gentleman was the Inventor of the Telescope, he probably was the first too, who must have had the great Pleasure of viewing the Moons of this Planet.

Cleon. It is natural for you to imagine fo; but this, however, was not the Cafe; for his Telescope, by which he faw the Ring, was not fufficient to fhew the Moons, as it magnified only about 30 Times; but one that will exhibit a View of all Saturn's Satellites must have a much greater magnifying Power. This happy Spectacle was referved to reward the Ingenuity of the celebrated Hugenius, who tells us, in his Treatife, called The Celestial Worlds difcovered, that the 4th of Saturn's Moons, (which is the largest and brighteft of all) he firft difcovered in the Year 1655, with a refracting Telescope, not above 12 Feet long; the other four were discovered by the industrious Caffini, an Italian Philofopher, who had the Opportunity of much longer Telescopes, viz. from 30 to 136 Feet long; the 3d and 5th he difcovered in the Year 1671, and the two Innermoft in the Year 1686; at Length, he could view all the Five with a 34 Foot Tube. He gave them the Title of Sidera Lodoicea, in Honour of Louis le Grand, in Imitation of Gallileus, who, fome Years before, had discovered the four Satellites of Jupiter, and called them by the Name of Medicea Sidera, in Compliment to Medicis II. Great Duke of Tuscany, to whom he addrefied this Difcovery, in the Year 1610; but enough of this at prefent; for I intend to put into your Hands very foon, the before-mentioned Book of Hugenius, wherein you will be highly entertained with the most P 2

inge

He advertised this Difcovery in this Sentence, Altiffimam Planetam tergenimum obfervavi. In which all the Letters were tranfpofed, as was the Cuftom of thofe Times in fuch new Discoveries.

ingenious Conjectures concerning the Inhabitants, Plants, and Productions of the Worlds in the Planets. You have read Fontenelle's Plurality of Worlds in French; but you will find this Treatife of Hugenius far fuperior to that, and much better worth Perufal.

your

Euphrof. That Book, or any other that you fhall recommend, I fhall be very ready to perufe, as I know you can judge what is calculated for the Improvement of my Understanding. But what is that little thing I fee in your Hand?

Cleon. This is a small Piece of Machinery, which I promised you fome Time ago, by which I intend to give you a farther Illuftration of that one remarkable Particular in the Moon, viz. her fhewing always the fame Face to the Earth, which we fome Time ago touched upon, but abruptly left it, as there was no proper Machinery in the Orrery to reprefent it in fo natural a Manner as was neceflary to convince you of the true Reafon of the Thing; nor muft I allow you to afk me any Questions concerning any particular Part of this Apparatus, which I fhall now place upon the Orrery.—I take the common Earth and Moon away, and adding this in the room, fee the whole is become new.

you

Euphrof. I obferve it with great Pleasure.When I turn the Handle, I fee no annual Motion of the Earth, only the diurnal Motion about its Axis.—I see a little Ball hang by a String, which, I fuppose, represents the Moon, with that Part of it next the Earth enlightened, and variegated with Spots, and brighter Parts, like what I fee in the Face of the full Moon itself through the Telef

cope.

Cleon. That pendulous Ball does, indeed, represent the full Moon; for you fee it is now in Oppofition to the Sun; but what you are particularly to take Notice of, is, that while the Earth moves upon its Axis, the Moon is moving about the Earth, in such a Manner, as always to turn the fame Part towards the Earth, as you fee before the Moon did, which we removed from the Orbit; but here it is owing to a very different Cause from that in common Orreries, and Planetariums. This Effect is there produced by a well-known Piece of Machinery; but here it is owing to the fame Caufe, as in the Heavens, where you find neither Wheels nor Pullies to produce it.

Euphrof. I am at a Lofs to guess what this invifible Agent fhould be.I fee, that the Moon turns constantly the fame Face to the Earth in her monthly Courfe.obferve, at the fame Time, that the vifible Part is more or less enlightened, and fometimes wholly dark; but I can fee nothing that produces this, unless it be the String by which it is fufpended.-How this String fhould caule it, I cannot conceive, as it is only hung on a brass Stem by a Loop. I cannot fay, but this looks most like Conjuration of any Thing I have seen yet. How am I to understand it, Cleonicus?

Cleon. Very eafily, my Euphrofyne. There is nothing that will be difficult for you to understand, or that requires any magic Art to account for. Mechanics itfelf is only the Application of natural Powers to produce the Effects in Miniature, which we fee in the World at large; nor does it follow, that, to answer this End, Wheels, Pullies, and other mechanical Contrivances, are always neceffary. We may, fometimes, fubftitute fimilar Powers in Nature for producing the fame Effects. Two Bodies will be actuated alike by the Powers of Gravity and Magnetifm. If they are affected by thefe Powers only, they will always turn the fame Parts towards each other. If one of them is fixed, and the other free to move, the latter will always turn the fame Part to the former. And this is the Cafe before us. For the Earth is placed upon one End of an artificial Magnet, which was covered from your Sight, and in the pendent Moon, you will prefently fee a round natural Load-ftone is included, like a Kernel within a Shell, and the Power of Magnetifm in these two Bodies, equally affecting both, caufes, that the Moon, hanging in a free State, muft always turn the fame Part toward the central magnetic Body of the Earth, juft as the Moon in the Heavens is made to do the fame Thing, by the Power of Gravitation, towards the Globe of our Earth.- -You will by this Time understand it. See, here are both the Magnets.

Euphrof. This delights me extremely, Cleanicus, and I perfectly comprehend you. This is down-right Nature, indeed, and fufficiently convinces me how fimple the Powers of Nature are, when compared with the complicated Contrivances of the moft ingenious Mechanic.

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But

But what are the Confequences, Cleonicus, that follow this curious Effect?

Cleon. The firft is, that the Moon neceffarily turns once round her Axis, in the fame Time that fhe moves once round the Earth; for by this Means, a Perfon on the Moon's Surface, with his Eye directed conftantly to the Earth, muft unavoidably view every Point in the Circumference in the Moon's Orbit, in the Time of one Revolution; but this he could not do, without being turned once round the Center of the Moon, at the fame Time.Do you apprehend me, Sifter?

Euphrof. I do very clearly; as I cannot but know, that to view every Point of a Circle, in which I am included, I muft certainly turn myself once round.But there is another Thing, I obferve, and that is, that thofe People who are on the other Side of the Moon cannot poffibly come at a Sight of the Earth at all.

Cleon. It is very true, they cannot, unless they will be at the Trouble of a Journey to that Hemifphere next the Earth; and fome of them, for this Purpose, must travel more than 1500 Miles.Another Thing you will as readily obferve, that those who inhabit the middle Part of the Surface of the Moon, next the Earth, will fee the great Globe of the Earth conftantly hanging over their Heads in the Zenith, while thofe, who live in the most Eastern or Western Parts of the faid Hemifphere, will fee one Half of our Globe in their weftern or eaftern Horizon.

Euphrof. Well! this is all very ftrange; but ftill, I fee, that it must be fo.-I fhould be glad to have the Pleasure of fuch Views of the Earth myself; and were it poffible, to get to the Moon, and if you could go with me, I should

almoft be induced to fet out.

Cleon. Confider every Thing, my Euphrofyne, and you will not be in fuch a Hurry to leave the Earth. You will find 240,000 Miles a tedious, aerial Journey, and you will find no Caitles in the Air, nor Inns of Accommodation on the Road; and which is worst of all, when you come there, it will be neceffary for you to have the Art of flying inftead of walking, as fome of their Mountains are more than nine Miles perpendicular Height, and their Vallies 2 or 300 Miles deep, and as much over; fo that, I fear, you will make but a poor Shift there.Befides,