| XXX | (470) | XXX |
47° ASTRO N O M Y. the 6 degrees of the fun’s motion in that time had been As the moon can never be full but when fhe is oppoallowed for. At the firft turn the patch rifes fouth of fhe to the fun? and the fun is nevief jn Virgo., and Libra the eaft, at the middle turn due eaft, and at the laft turn but in our autumnal months, it is plain that the moon is north of the eaft. . But thefe patches will be 9 hours of never full in the oppofite figns, Pifces and Aries, but in' fetting on the weftern fide of the horizon, which fhews thefe two months. And therefore we can have only two that the moon will be fo much later of fetting in that full mbons in the year, which rife fo near the time of week in which fhe moves through thefe two figns. The fun-fet, for a week together, as above mentioned. The daufe of this difference is evident ; for Pifces and Aries former of thefe is called the harvejl-moon, and the latter make only an angle of 15 degrees with the horizon when the hunter's moon. they rife ; but they make an angle of 62 degrees with Here it will probably be afked,- Why we never obit when they fet. As the figns Taurus, Gemini, Can- ferve this remarkable rifing of. the moon but in harveft, cer, Leo, Virgo, and Libra, rife fuccefEvely, the angle fince fhe is in Pifces and Aries twelve times in the year increafes gradually which they make with the horizon; befides.; and muft then rife with as little difference of atftl decreafes in the fame proportion as they fet. And time as in harveft? The anfwer is plain: for in winter for that reafon, the moon difi’ers gradually more in the thefe figns rife at noon ; and being then only a quarter time of her rifing every day whilft fhe is in thefe figns,1 of a circle diftaht from the fun, the moon in them is in and lefs in her fetting : after which, through the other her firft quarter: But when the fun is ^.boye the horizon, fix figns, viz. Scorpio, Sagittary, Capricorn, Aqua- the moon’s rifing is neither regarded nor perceived. In rius, Pifces, and Aries, the rifing difference becomes fpring thefe figns rife, with the fun, ’becaufe he is then in lei's every day, until it be at the leaft of all, namely, in them ; and as the moon changeth in them at that time of Pifces and Aries. the year, fhe is quite invifible. In furomef they rife aThe moon goes round the ecliptic in 27 days 8 hours; b'out midnight, and the fun being then three figns, or a but not from change to change in lefs than 29 days 12 quarter of a circle before them, the moon is in them ahours : fo that fhe is in Pifces and Aries at leaft once in bout her third quarter,; when rifing fo late, and giving every lunation, and in fome lunations twice. But very little light, her rifing paifes unpbferved. And If the earth had no annual motion, the fun would ne- in autumn, thefe figns, being oppofite to the fun, rife ver appear to fhift his place in the ecliptic. And then when he fets, wirh the moon in‘oppofition, or at the every new moon would fall in the fame fign and degree' full, which makes her rifing. very confpicubus. of the ecliptic, and every full moon in the oppofite ; for At the equator, the north and fouth poles lie in the, the moon would go precifely round the ecliptic from horizon; and therefore the ecliptic makes the fame anchange to change. So that if the moon was once full gle fbuthward with the horizon when Aries rifes, as it in Pifces or Aries, fhe would always be full when fhe does northward when Libra rifes. Confequently, as the came round to the fame fign and degree again. And as moon at all the fore-mentioned patches rifes and fets the full moon rifes at fun-fet (becaufe when any point of nearly at equal angles with the horizon all the yea,r the ecliptic fets, the oppofite point rifes) fhe would con- round, and about 48 minutes later every day or night ftantly rife within two hours of fun-fet, on the parallel than on the preceding, there can be no particular harof London, during the week in which fhe were full. veft-moon at the equator. But in the time that'the moon goes round the ecliptic The farther that any place is from the equator, if it be from any conjunflion or oppofition, the earth goes almoft not beyond the polar circle, the angle gradually dimia fign forward ; and therefore the fun will feem to go as nilhes which the ecliptic and horizon make when Pifces far forward in that time, namely, 27-I- degrees; fo that and Aries rife: And therefore, when the moon is in thefe the moon muft go-2 74- degrees more than round, and as figns ftie rifes with a nearly proportionable difference much farther as the fun advances in that interval, which later every day than on the former; and is for that reais 2 -rs- degrees, before fhe can be in conjunction with, or fbn the more remarkable about the full, until we come oppofite to, the fun again» Hence it is evident, that to the polar circles, or 66 degrees from the equator ; in there can be but one conjunction or oppofition of the fun which latitude the ecliptic and horizon become coincident and moon in a year in any particular part of the ecliptic. every day for a moment, at the fame fydereal hour, (or This may be familiarly exemplified by the hour and mi- 3 minutes 56 feconds fooner every day than the former),, nute-hands of a watch, which are never in conjunction or and the very next moment one half of the ecliptic, conoppofition in that part of the dial-plate where they were taining Capricorn, Aquarius, Pifces, Aries, Taurus, fo laft before. And indeed, if we compare the twelve and Gemini rifes, and the oppofite Half fets. Therehours on the dial-plate to the twelve figns of the ecliptic,, fore, whilft the moon is going from the beginning of Cathe hour-hand to the fun, and the minute-hand to the pricorn to the beginning of Cancer, which is almoft 14 moon, we fhall have a tolerably near refemblance in mi- days, file rifes at the fame fydereal hour; and in autumn, niature to the motions of our great celeftial luminaries. juft at fun-fet, beeaufe all that half of the ecliptic, in The only difference is, that whilft the fun goes once which the fun is at that time, fets at the fame fyround the ecliptic, the moon makes 124 conjunctions dereal hour, and the oppofite half rifes ; that is,. 3 miwith him : but whiffi'the hour hand goes round the dial- nutes 56 feconds, of mean folar time, fooner every day plate, the minute-hand makes only 11 conjunctions with than on the day before. . So, whilft the moon is going it; becaufe the minute-hand moves flower in refpeCt of from Capricorn to Cancer, ftie rifes earlier every day the hour-hand than the moon does with regard to the fun. than on the preceding, contrary to what ftie does places at alt
