I have found another
clue that supports the theory that these are cross-sections of plants.
Image 85 ( below right the page with the plant cross-sections)
It is a process description:
The first thing that stands out is the circle with the three lines. When you cut a plant stem crosswise, the first thing you see is a clear outer circle, the epidermis + hypodermis – there are indications that these three lines could refer to the fibrous structure.
Inside the circle is a symbol that is an alchemical process symbol. I found it in LA:
Triple-distilled vinegar. Since these alchemical process symbols often indicated 1, 2, or 3, it stands to reason that the one with two legs represents a two-step process. (Why not three times? Perhaps because it would damage the plant too much.)
Vinegar also makes sense: in the Middle Ages, pigments were often processed with vinegar.
If you treat a cut plant stem with vinegar, the following happens:
The vinegar slightly attacks the soft cell walls and saturates the tissue. The ink runs mainly into areas where there are cavities and capillaries: conducting vessels, cracks, softer areas. Harder, heavily lignified zones absorb less and tend to remain lighter in color.
If you then press the stem onto paper like a stamp, you get:
A darker circle where there are many vessels/conducting bundles. A differently colored area in the pith (inside) and in the bark on the outside, depending on the plant. Individual dots or rings of dots if the vascular bundles are clearly separated.
This means that you would get a picture of the distribution of “soft vs. hard / hollow vs. compact” – in other words, a kind of structural fingerprint of the stem – as we see here on these pages.
Then you just need to stamp it several times and use a slightly stronger reading stones (magnifying glass), which already existed in the Middle Ages.
That would also explain why the
colored plant cuttings I have shown here fit so well with the circles here.
PS: I looked it up: triple distilled. With vinegar, the water would evaporate beforehand because water boils at around 100 °C and pure acetic acid only at around 118 °C. The remaining liquid would then be more concentrated
From around the second half of the 13th century onwards, very good reading stones were already being made from rock crystal, for example. By 1300, the same glass and grinding techniques had led to the first spectacles, showing that the quality of the lenses was sufficient for precise optical applications.