Marco wrote:
[/url]
Quote:[url=http://www.thedigitalwalters.org/Data/WaltersManuscripts/html/W73/description.html]Walters Ms. W.73
, Bede's Cosmography (England, XII Century) features a diagram of the tides (You are not allowed to view links.
Register or
Login to view.).
The four circles in the corners refer to high ("malina") and low ("ledona") tides.
Thanks, Marco! As I understand, that diagram reflects monthly (lunar) four tides, which exactly relate to the four Moon phases: Full Moon and New Moon (high tides), First Quarter Moon and Third Quarter Moon (low tides).
The diagram of f67v2 is extremely interesting, as I think, the author tried to depict there all three cycles (for Posidonius). I don't remember where I read the full text, I'll try to find that quote later, but now I can give only this:
![[Image: content?id=6kpoAAAAMAAJ&hl=ru&pg=PA68&im...GwQ&edge=0]](https://books.google.com.ua/books/content?id=6kpoAAAAMAAJ&hl=ru&pg=PA68&img=1&pgis=1&dq=moon+tides+%22three+cycles%22+diurnal&sig=ACfU3U01fwa45BtZH6pRQ3NB4hbH_iqGwQ&edge=0)
So, I think the three schemes (the left low, the right low and the right top) can depict just those cycles: daily tides, connected to the place of the Moon in the sky (four quarters) during 24 hours; monthly tides - connected to phases of the Moon; annual tides - increased in solstices (neap tides) and in equinoxes (spring tides).
Davidjackson wrote:
Quote:Obviously medieval people linked phases of the moon to tides, even if they didn't know why. Roger Bacon's theory was that the moon caused the tides in oceans, but he believed this was because the rays of light from the moon “raise vapours” from the sea, which cause the waters to move. When the moon was overheard, these rays evaporated the water, which made the tide recede.
The original quote is very amusing. When I read this, my thought that the left low "lunar pipe" means
evaporation became just WOW!
"Wherefore we must consider that when the moon rises over the sea of any region, its rays fall at oblique angles, as any one acquainted with the incidence of angles knows. And because they fall at such angles, the rays are necessarily of weak force, as has been shown before. And therefore they are only able to raise vapors from the depth of the sea, like swelling bottles, and overflowing waters of the sea, so that they are driven from their channels. These vapors the rays cannot draw out to the air nor consume them because of their weakness; and therefore of necessity the water flows from its resting places, as long as this kind of ebullition lasts. But when the moon approaches the middle of the sky, the rays fall more and more at right angles and become strong over the body of the sea and draw forth the vapors to the air and consume them, whence the flow grows weaker little by lirtle according to the moon's approach to the meridian; and when she reaches it, the vapors are kept in check and consumed, so that at once while the moon is descending to another quarter of the heavens, the reflux begins, since the effect ceases when the cause ceases. "
Koen wrote:
Quote:If you imagine the orb as the earth surrounded by a green belt of water, you actually see the water rise in four high points where the heavenly bodies are above it.
Yes, I have the same impression.
Quote:Also, there are dots connecting the "peaks" to their respective heavenly body.
Thank you! I have really missed them!