f72v1 - Thirteen circle segments (volvelle)

[bi3mw]

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Seems to me that you've imposed on the drawing a type of diagram that's common enough in medieval texts about science, but which has never yet assisted our knowledge of the ms (though it has helped pad out holes in a number of tenuous theories).
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Yes, triangles like this have been used to construct diagrams. The following example shows a corresponding sketch:



Or 10878, British Library, Collection of scientific works, 1400-1449, folio You are not allowed to view links. Register or Login to view. .

It is upside down, but that doesn't matter for the method. The missing baseline of the big triangle is also unimportant. I have only drawn it to check whether the division by the vertical line creates a certain aspect ratio of the sections or not. It's only important that position and height / angles are well comparable. - Hard to believe that the triangle in f72v1 is just a coincidence at this position.

In my opinion, any process that can be reproduced in f72v1 makes it possible to draw concrete conclusions about the content. For example, if the number of circle segments in the inner circle are actually 13, then speculations about the outer circle would not be that wild anymore. Your reference to the 4-week months is of course an obvious thought