That the Heavens are encompassed with 7 Circles, is also the allegation of Philo; which are in his account, the Arctick, Antarctick, the Summer and Winter Tropicks, the Æquator, Zodiack, and the Milky circle; whereas by Astronomers they are received in greater number. For though we leave out the Lacteous circle (which Aratus, Geminus, and Proclus, out of him hath numbred among the rest) yet are there more by four then Philo mentions; that is, the Horizon, Meridian and both the Colures; circles very considerable, and generally delivered, not only by Ptolomie, and the Astronomers since his time, but such as flourished long before, as Hipparchus and Eudoxus. So that for ought I know, if it make for our purpose, or advance the theme in hand, with equal liberty, we may affirm there were 7 Sybils, or but 7 signs in the Zodiack circle of Heaven.
That verse in Virgil translated out of Homer Τρὶς μάκαρες Δαναοὶ καὶ τετράχις., O terque quaterque beati; that is as men will have it, 7 times happy, hath much advanced this number in critical apprehensions; yet is not this construction so indubitably to be received, as not at all to be questioned: for though Rhodiginus, Beroaldus, and others from the authority of Macrobius so interpret it, yet Servius his ancient commentator conceives no more thereby then a finite number for indefinite, and that no more is implied then often happy. StraboLib. 10. the ancientest of them all, conceives no more by this in Homer, then a full and excessive expression; whereas in common phrase and received language, he should have termed them thrice happy; herein exceeding that number, he called them four times happy, that is, more then thrice. And this he illustrates by the like expression of Homer, in the speech of Circe; who to express the dread and terrour of the Ocean, sticks not unto the common form of speech in the strict account of its reciprocations, but largely speaking, saith, it ebbs and flows no less then thrice a day, terque die revomit fluctus iterumque resorbet. And so when it is said by Horace, fælices ter et amplius, the exposition is sufficient, if we conceive no more then the letter fairly beareth, that is, four times, or indefinitely more then thrice.
But the main considerations which most set of this number, are observations drawn from the motions of the Moon, supposed to be measured by sevens; and the critical or decretory daies dependent on that number. As for the motion of the Moon, though we grant it to be measured by sevens, yet will not this advance the same before its fellow numbers; for hereby the motion of other Stars are not measured, the fixed Stars by many thousand years, the Sun by 365 daies, the superiour Planets by more, the inferiour by somewhat less. And if we consider the revolution of the first Movable, and the daily motion from East to West, common unto all the Orbs, we shall find it measured by another number, for being performed in four and twenty hours, it is made up of 4 times 6: and this is the measure and standard of other parts of time, of months, of years, Olympiades, Lustres, Indictions of Cycles, Jubilies, etc.
What a Solary month is.
Again, Months are not only Lunary, and measured by the Moon, but also Solary, and determined by the motion of the Sun; that is, the space wherein the Sun doth pass 30 degrees of the Ecliptick. By this month HippocratesDe octomestri partu. computed the time of the Infants gestation in the womb; for 9 times 30, that is, 270 daies, or compleat 9 months, make up forty weeks, the common compute of women. And this is to be understood, when he saith, 2 daies makes the fifteenth, and 3 the tenth part of a mouth. This was the month of the ancient Hebrews before their departure out of Egypt: and hereby the compute will fall out right, and the account concur, when in one place it is said, the waters of the flood prevailed an hundred and fifty daies, and in another it is delivered, that they prevailed from the seventeenth day of the second month, unto the seventeenth day of the seventh. As for hebdomadal periods or weeks, although in regard of their Sabbaths, they were observed by the Hebrews, yet it is not apparent the ancient Greeks or Romans used any: but had another division of their months into Ides, Nones and Calends.
Moreover, Moneths howsoever taken, are not exactly divisible into septenaries or weeks, which fully contain seven daies: whereof four times do make compleatly twenty eight. For, beside the usual or Calendary month, there are but four considerable: the month of Peragration, of Apparition, of Consecution, and the medical or Decretorial month; whereof some come short, others exceed this account. A month of Peragration, is the time of the Moons revolution from any part of the Zodiack, unto the same again; and this containeth but 27 daies, and about 8 hours: which cometh short to compleat the septenary account. The month of Consecution, or as some will term it, of progression, is the space between one conjunction of the Moon with the Sun, unto another: and this containeth 29 daies and an half: for the Moon returning unto the same point wherein it was kindled by the Sun, and not finding it there again (for in the mean time, by its proper motion it hath passed through 2 signs) it followeth after, and attains the Sun in the space of 2 daies and 4 hours more, which added unto the account of Peragration, makes 29 daies and an half: so that this month exceedeth the latitude of Septenaries, and the fourth part comprehendeth more then 7 daies. A month of Apparition, is the space wherein the Moon appeareth (deducting three daies wherein it commonly disappeareth; and being in combustion with the Sun, is presumed of less activity,) and this containeth but 26 daies and 12 hours. The medical month, not much exceedeth this, consisting of 26 daies and 22 hours, and is made up out of all the other months. For if out of 29 and an half, the month of Consecution, we deduct 3 daies of disappearance, there will remain the month of Apparition 26 daies and 12 hours: whereto if we add 27 daies and 8 hours, the month of Peragration, there will arise 53 daies and 10 hours, which divided by 2, makes 26 daies and 22 hours: called by Physitians the medical month: introduced by Galen against Archigenes, for the better compute of Decretory or Critical daies.
What a Critical day is.
As for the Critical daies (such I mean wherein upon a decertation between the disease and nature, there ensueth a sensible alteration, either to life or death,) the reasons thereof are rather deduced from Astrology, then Arithmetick: for accounting from the beginning of the disease, and reckoning on unto the seventh day, the Moon will be in a Tetragonal or Quadrate aspect, that is, 4 signs removed from that wherein the disease began: in the fourteenth day it will be in an opposite aspect: and at the end of the third septenary, Tetragonal again: as will most graphically appear in the figures of Astrologers, especially Lucas Gauricus, De diebus decretoriis.
Again, (Beside that computing by the Medical month, the first hebdomade or septenary consists of 6 daies, seventeen hours and an half, the second happeneth in 13 daies and eleven hours, and the third but in the twentieth natural day) what Galen first, and Aben-Ezra since observed in his Tract of Critical daies, in regard of Eccentricity and the Epicycle or lesser orb wherein it moveth, the motion of the Moon is various and unequal; whereby the Critical account must also vary. For though its middle motion be equal, and of 13 degrees, yet in the other it moveth sometimes fifteen, sometimes less then twelve. For moving in the upper part of its orb, it performeth its motion more slowly then in the lower; insomuch that being at the height, it arriveth at the Tetragonal and opposite signs sooner, and the Critical day will be in 6 and 13; and being at the lowest, the critical account will be out of the latitude of 7, nor happen before the eighth or ninth day. Which are considerations not to be neglected in the compute of decretory daies, and manifestly declare that other numbers must have a respect herein as well as 7 and fourteen.