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13-05-2020, 08:12 PM
(This post was last modified: 14-05-2020, 08:30 AM by Searcher.
Edit Reason: edited link, correction
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I reread the thread and found the link to You are not allowed to view links. Register or Login to view. provided by MarcoP (in You are not allowed to view links. Register or Login to view.) . Of course, I remember its tidal diagram (You are not allowed to view links. Register or Login to view.), but now I was interested in the library description to it.
It contains such lines:
"Simple versions of the tidal diagram occur in scientific manuscripts from the Carolingian period on. The tidal rota on W.73, fol. 8v is a hybrid that fuses the basic tidal diagram with early wind rotae. This combination reflects Bede’s assertion that the winds effect the movement of the tides. For a tidal diagram similar to the one in W.73, see London, British Library Harley MS 3017, fol. 135r, a computus manuscript made after 861 CE at Fleury or Nevers in northeast France."
It is really similar, but a little simplier.What I'm quite interested is in those simple tidal diagrams which are also mentioned in the description text. But however I try to find any of them, I find nothing. Maybe, someone knows where to search.
The second point that attracted me again is the hat of one of the "faces" in the right bottom corner. David Jackson supposed (in You are not allowed to view links. Register or Login to view.) it is a "jewish hat". Now I have a question: Could this hat be a sign of any celebration, supposedly Jewish? May it signify, for example, Passover?
I didn't pay attention before, but it turns that the celebration of Passover coincides with Spring edited : spring tides which are the highest tides for a year. It unites the two celestial events causing tides: march equinox and the Full Moon.
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13-05-2020, 08:58 PM
(This post was last modified: 13-05-2020, 09:08 PM by arca_libraria.
Edit Reason: Edited to fix an error in a manuscript number.
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Some more tidal diagrams:
Oxford, St John's College MS 17, f. 8r has a tidal diagram like this one. Here's a link to some high resolution digital images [You are not allowed to view links. Register or Login to view.]. Here's a website all about the St John's College manuscript, it has lower resolution images, but it was written by one of the world experts on medieval science and medicine [You are not allowed to view links. Register or Login to view.].
The Calendar and the Cloister website lists some other (11th and 12th century) manuscripts with tidal diagrams:
Cambridge, St John's College, I.15
Cambridge, Trinity College, O.2.45
Oxford, Bod Lib., Auct F.5.19
Paris, BNF, Lat. 7299a
Berlin, Staatsbib., Preussicher Kulturbesitz, Lat. 138
London, BL, Harley 3017
Montecassino Computus (no shelf mark provided)
Paris, BNF, Lat. 5543
Paris, BNF, Nouv. Acq. Lat. 1615
Paris, BNF, Nouv. Acq. Lat. 1616
London, BL, Cotton Julius A.vi
Baltimore, Walters Art Gallery, MS 73
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(13-05-2020, 08:58 PM)arca_libraria wrote: You are not allowed to view links. Register or Login to view.Some more tidal diagrams:
... Thank you very much! I'll look at them tomorrow.
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Spring tides are not "Spring" tides, but "spring" tides. They are not related to the season of Spring. They occur twice in a lunar month.
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14-05-2020, 08:32 AM
(This post was last modified: 14-05-2020, 08:34 AM by Searcher.)
(13-05-2020, 10:28 PM)Anton wrote: You are not allowed to view links. Register or Login to view.Spring tides are not "Spring" tides, but "spring" tides. They are not related to the season of Spring. Oh, really confused! Thanks for the remark!
Quote:They occur twice in a lunar month.
... and twice in a year.
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(14-05-2020, 08:32 AM)Searcher wrote: You are not allowed to view links. Register or Login to view.... and twice in a year.
No, only twice per month, namely when sun, moon and earth are (approximately) on one line.
The official name is twice per synodic month, and this is about 29.5 days long.
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(14-05-2020, 08:51 AM)ReneZ wrote: You are not allowed to view links. Register or Login to view. (14-05-2020, 08:32 AM)Searcher wrote: You are not allowed to view links. Register or Login to view.... and twice in a year. No, only twice per month, namely when sun, moon and earth are (approximately) on one line.
The official name is twice per synodic month, and this is about 29.5 days long. I was sure that the annual tides also are named spring. Maybe, it is just my headache, provoced by cyclone and wind.
Exactly Bede, in "De Temporum ratione" , the diagram of which was mentioned earlier, noted the increase of tides at the equinoxes and their decrease at the solstices. It is strange that he didn't draw this grafically. Possibility, it is because he initially thought ("De natura rerum") that the tides are increased at equinoxes and at solstices either. So, it was a questionable moment.
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I checked, in some old books (18th c.), predominantly of the Royal Society (Great Britain), they are called "annual spring tides", meaning equinoctial tides in March and September.
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The article which I linked above provides a survey of the history of tidal concepts from Antiquity to Middle Ages.
I did not find anything of great interest with respect to 67v2 there. But the important thing (and I never thought before in that line) is that tides are weak in the Mediterranean, so I can suppose that anybody including tidal diagrams (implying that tides are a significant factor) would, with good probability, be an observer of the outer Atlantic coast or, at least, an inhabitant of the regions such as France, Spain or England, not e.g. Switzerland or Italy. I wonder what are the places of origin of those MSs that arca_libraria listed.
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(14-05-2020, 03:00 PM)Anton wrote: You are not allowed to view links. Register or Login to view.The article which I linked above provides a survey of the history of tidal concepts from Antiquity to Middle Ages.
I did not find anything of great interest with respect to 67v2 there. But I seem to find something interesting for you. I'll write later, hope, today
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