Euphrof. So far I understand you; but I fear left what is to come should prove a much greater Trial of Skill.

Cleon. There is no Grounds of Fear to you, Sifter; if you attend to the following Precepts, every Thing will be easy. First, obferve in the Ephemeris the Heliocentric Place of each Planet, and bring the Label of the Planet to that Sign and Degree in the Heliocentric Ecliptic, that is, fo that the Line which paffes through the Center of the Planct may cut that Degree.

Secondly, Having done this for every Planet, fix them down to their proper Places in their Orbits by a fmall Pin through their Centers.

Thirdly, Bring the Earth to its Heliocentric Place, and fix the Label by a Pin passed through it into the Board. Fourthly, The Geocentric Ecliptic is then to be moved about the Earth, and placed in fuch a Manner, that the Line of paffing through the Earth's Center, may be parallel to or equally diftant from the fame Line of in the Solar Ecliptic, which you may easily do by the Eye. Fifthly, This Geocentric Ecliptic fo rectified, is to be fixed by a Pin through that Part of it which lies remote from the Sun.

Sixthly, Then in the laft Place, ftrain a Thread over the Center of the Earth and each refpective Planet, and that' will cut the Geocentric Ecliptic in that Point where the Planet will appear to an Eye at the Earth. And thus with a little Practice, you will be able immediately to exhibit the Syftem of Planets, both as it is in it's Self, and as it appears to us at any Time.

of the Circle of the Signs, and the Diameter between the black Lines; and let the Center of this be placed on a Thread through the Center of the Earth on the Label, and tied down on it, fo that it may freely move about the Earth's Center. Then is it fit to be used, as in the Dialogue above is directed.

5. To fit this Inftrument for Jupiter and Saturn, it must be ftuck on to the Side of a Room, or on a large round Table; you must then lay a Thread over the Center of the Sun, and Jupiter's Place in the Ecliptic about the Sun, and at 12 Inches from the Center, ftick a Patch, and it will be the true Place of Jupiter. For Saturn you do the fame, but for him you must place the Patch at the Distance of 23 Inches. And indeed, in this Manner, Patches may be placed on the Orbit of the other Planets, if the Trouble of the Labels be thought too much.

Euphrof. I make no Doubt but I fhall understand these Precepts very well, when I join with them the Practice, in which you will affift me a little at firft.

Cleon. That I fhall do in the next Place; therefore, to begin, take the Ephemeris and look in the Heliocentric Table for the Places of the Planets for the 26th Day of December next, and let me hear you say what they are for each Planet.

Euphrof. I willet me fee, the Planet Mercury is in 5° 38′ of Scorpio, (R) and therefore, I fuppofe, I muft take this Label of Mercury and bring the Edge of it to that Point of the Solar Ecliptic.-Well, here I fix it with a Pin, and what next, Cleonicus?

Cleon. You muft now proceed to do the fame with all the Reft; pray, where do you find the Planet Venus ? ? Euphrof. I find her Place to be in 8° 36' of Aquarius , to which I bring her Ladyfhip, and pin her fast down. The next I niuft look for is the Earth-I fee itwe are that Day in 4° 30′ of Cancer; thither I bring the Earth's Label, and fix it down with a Pinfo far I prefume I am right, Cleonicus?

Cleon. You proceed very well; do the fame by all the Reft, and you will erect a much better Scheme of the Heavens than any Aftrologer could ever yet pretend to. Euphrof. The Place of Mars & I fee is in 6° 40′ of Cancer -Jupiter is in 6° 16′ of Libra; and Saturn ↳ is in o° 12' of Aquarius.-To thefe Places I have brought, and pinned down their Labels-And now, what remains? Cleon. Only to rectify the Geocentric Ecliptic

Euphrof. I know what you mean,it is to place the Ecliptic about the Earth in a parallel Situation to that about the Sun-fee, there it is done.

Clean. With great Pleasure I fee how readily you do it; you have now nothing more to do, but to lay a Thread from the Center of the Earth over the Centers of the feveral Planets; and you will then obferve the Places in which they feverally appear in the Geocentric Ecliptic are the fame very nearly as thofe you fee in the other Table for the Geocentric Motions.

Euphrof. Indeed! that will give me great Pleasure-I'll try-I lay the Thread from the Earth over Mercury, and find it cuts the Geocentric Ecliptic in the 17° of Sagitta

rias-Now let me fee the Table,-Mercury's Place is there 17° 9' of the fame Sign.I think I am very near the Matter, Cleonicus?

Cleon. As near as you can defire or expect to be; for in Inftrumental Aftronomy, we must not ftand for a few Minutes. Well, and where do you find Venus, my Euphrofyne?

Euphrof. I will tell you prefently-I lay the Thread tight over Venus, and it cuts the Geocentric Ecliptic in 18° of Capricorn-Now to the Table-Her Place is there 18°: 56-How! that is almoft 19°-fure I am a little out here

Cleon. Not at all, Sifter; for unless the Degrees were very large, it is no Wonder if you mistake or a Degree now and then; it is enough, if by Inftruments we come but nigh the Mark.

Euphrof. Well, next for Mars-the String laid over that Planet cuts the Ecliptic in 10% of -in the Table I fee it is 10° 8'-pretty near.-I next extend the String to Jupiter's Center, and it cuts-let me fee-15° of;

in the Table, that Planet feen from the Earth, is in 16": 25′ of I am near the Truth here alfo.In the last Place, let me try for yonder Planet Saturn-I lay the Thread over his Center, and it cuts the Ecliptic in 28° of ;-in the Table it is 27° : 57', within 3' of the Truth. Cleon. By this Praxis, you fee, my Euphrofyne, how nearly the Inftrument and the Table agree; and how eafy it is in this Manner to represent the Situations and Aspects of the Planets for any other Time. The Reverfe of this Process is also very eafy, viz. to find the Heliocentric or true Places of the feveral Planets in their refpective Orbits, by laying a Thread from the Earth's Center to their apparent or Geocentric Places; for the Thread fo extended will always cut the Orbit of the Planet in the Place where it really is at that Time.

Euphrof. It is much easier than I thought it was, and will often be the Subject of my leifure Hours Amusement. But as you mentioned the Afpects of the Planets, 1 fhould be glad to know what is meant by the Lunar Afpects, and Afpects at the Earth, in a Table for every Day under the Heliocentric Motions.

Cleon. Thofe Tables of Afpects are of no great Importance; they only fhew us how the Planets are pofited with Refpect to the Moon in one Table, and with Refpect to

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each other, as feen from the Earth, in the other. And they ufe the Symbol A for the Trine Afpect, that is, when the Planets are a third Part of the Ecliptic diftant from one another, viz. 4 Signs; if they are but 3 Signs apart, that Afpect is called Quartile, denoted by □; if but 2 Signs from each other, it is called a Sextile, and is fhewn by this Mark *; if they are in Conjunction, it is fhewn by 6, and if in Oppofition by 8. And the Number placed by the Symbol, fhews the Hour after Noon, when that Afpect happens.

Euphrof. I believe I understand all that you have faid, Clenicus; but let me try if I can make it out by Experiment.

I obferve against the 26th of December (to use the fame Example as before) in the Column under Jupiter 4 there is placed 6 18, which I apprehend denotes the Planet is in Conjunction with the Moon at 18 Hours after NoonBut now, as there are but 12 Hours from Noon to Midnight, pray, what am I to understand by the 18th Hour, Cleonicus ?

Cleon. Why you are to reckon 18 Hours from Noon of the 26th; 12 of which will bring you to Midnight, and the other 6 will make 6 o'Clock in the Morning of the following Day; fo that the Conjunction happens on the 27th of December at 6 in the Morning.

Euphrof. Poh, that I could not think on fo eafy a Thing as that-well, what is the next Lunar Afpect that I fee against the fame Day-it is 7, in the Column of &, by which I fee Mars will be in its Quartile Afpect with the Moon, or 4 Signs from her, at 7 o'Clock that Night

Again: I fee in the Column of, the Afpect * 19, fhewing Mercury to be in Sextile with the Moon, at-let me think-19 is equal to 12 and 7-Oh, at 7 o'Clock the next Day.

Cleon. Very right; one Example more of the Afpects at the Earth will make you a perfect Mistress of this Part of the Science of the Stars.

Euphrof. That gives me no Trouble; for against the 25th Day, I fee the Characters, which thew that Jupiter 4 and Mercury feen from the Earth, have a Sextile Afpect, or are two Signs diftant from each other.

Cleon. Very well; and this you fee confirmed by the Geocentric Planetarium, and alfo by the Table of Geocentric Motions, for the Place of 2 is there 26°: 18′ of Libra, and the Place of Mercury is 15° : 41′ of

Sagittarius, which is near 2 Signs or 60 Degrees from the other. And as you are now ready in the Use of the Ephemeris, and can find the Places and Afpects of the Planets for any given Day, as they are seen, both from the Sun and Earth, we may proceed to the Ufe of the Stellated Planetarium, which is fomewhat different from what you have yet feen, and this fhall be the Subject of the next Converfation.