I've been sitting here on the sofa trying to think of a 43 cycle in medieval mythology / knowledge.
Now, IF this is a T/O style map then the undulations represent Oceanus, the world river. What significance could 43 have in relation with Oceanus?
Well, it strikes me that Britain was formally invaded by the Roman Empire in 43AD, but that's probably irrelevant here
More to the point, the undulations are obviously important to the scribe. Why? He hasn't used his compass to map it out. The inside of the circle is clearly marked out by mechanical means, but the undulations are (not very well) drawn by hand. One would assume that a competent scribe would have marked out the exterior ring and then done the undulations. After all, that's what he's done with the text.
But if we actually examine the circles, we see that the undulations
are not a single line. They are doubled up, with an inner and outer line. Almost like a 3D effect.
We can also see that the lines of incoming text that terminate at the exterior radius (2,18,23,34 in Sale's diagram) were drawn at the same time as the undulation, suggesting that they were pre-planned and considered to be important at that point - these could be, we assume, the terminii that JKP suggested. There is no obvious mathematical symmetry to the number of undulations between them.
And the incoming lines of text that terminate at the inner radius of text (at points 7,14,18,27,39) were obviously drawn first.
My point is that the undulations appear to have
been forcibly drawn to a set number between the lines of incoming text.
Is there a pattern?
The outer lines transact at undulations: 2,14,23,34
Their degrees of separation are thus: 11,12,9,11
The inner lines transact at undulations: 7,18,27,39
Their degrees of separation are thus: 11,11,9,12
The degrees of separation between inner and outer lines are: 5,7,4,5,4,7,5
[(2,7)
5,(7,14)
7,(14,18)
4,(18,23)
5,(23,27)
4,(27,34)
7,(34,39)
5]
Damned if I can see a pattern there. Unless it's something obscure such as lines from the Bible. Nor can I see any matches with other star counts from this section.