> Togeher with the message by Roger Baily about an English translation of > Sacrobosco's text we have more sources that say that at least there is a > timesystem in history based on the rise of 15 degrees of the elcliptic, no > matter what name is used for it. > I hope to hear about more sources. -----------------
For now I have ready a passage from the Astronomicon of Manilius (ante a.D. 14), probably contesting the belief of a uniform motion of the zodiac, with rise of half Sign in 1 hour, he writes in his "Astronomicon" (hope the English translation is good enough): " Nor am I unaquainted with a common method of calculating, which attributes two hours each to the rising of the signs and reckons the stars as identical with equal ascensions; by this calculation, starting from the point where the Sun's orbit begins, the number of the hours is counted, with its total converted into signs, until it reaches the precise time of birth" (Manilius is writing about horoscope) and he follows "Who could believe that, with such uneven periods and such changeable limits of the day and darkness, all the signs rise into the sky under a uniform law of heaven? Moreover, the length of an hour is a variable quantity, nor is any hour followed by another of the same length, but just as the duration of days varies, so also their parts increase and again decrease; and yet, under whatever signs a day's course is run, it has at any moment six signs above the earth and six below. It follows that the signs cannot all rise in a period of two hours, since owing to the discrepancy between the hours their duration is not uniform, if indeed twelve hours are contained between each down and dusk, a number which ordinary reckoning demands but strict application does not permit."[i] Martianus Capella also knew this lesson (see Martianus, De Nuptiis, VIII, 844). In medieval time you often find the description of an hour as "the 12th of the daylight" and "half sign rise in one hour", but of course this is wrong because one half of a sign doesn't rise in one hour (temporal hour, of course) but faster if it rise oblique and slower if it rise right. So William of Conches understanding this lesson say in his Dragmaticon Philosophiae, IV: "The hour is the time that one half of sign rise", but he add an explanation about this time and he says: "six sign are everyday on the horizon and six down ... even if they are equal (six up and six down) some of them are slower and some of them are faster, because some of them rise right and set oblique, some other rise oblique and set right...". Yes it is true, the name of 'planetary' hours is not written, but they are actually a real horary system bind to the movement of the ecliptic, and zodiac and we know that every sign is under a planet influence. Mario -------------------------------------------------------------------------------- [i] "In tam dissimili spatio variisque dierum umbrarumque modis quis credere possit in auras omnia signa pari mundi sub lege meare? Adde quod incerta est horae mensura neque ullam altera par sequitur, sed, sicut summa dierum vertitur, et partes surgunt rursusque recedunt; cum tamen, in quocumque dies deducitur astro, sex habet supra terras, sex signa sub illis. Quo fit ut binas non possint omnia nasci, cum spatium non sit sibi par pugnantibus horis, si modo bis senae servantur luce sub omni, quem numerum debet ratio sed non capit usus."; M. Manilius, Astronomica, III, 235, G.P. Goold ed., The Loeb Classical Library, Harvard University Press, Cambridge (Massachusetts), London (England), 1977, pp. 178-181, (LCL 469). --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
