Those umbrella/pinecone things

[MarcoP]

... The tent+mountain/stream composition seems to me likely to represent something different from tents and possibly from mountains too.

At least a connection from alchemical, "liquid streams" from the mountains to balneology would be conceivable. The study of metallic, mineral and sulfur spas ( You are not allowed to view links. Register or Login to view.  ) was a kind of "secondary discipline" of alchemy. At least there was a clear overlap of the fields of work. It was not about transmutation, but about the "analysis" of spa waters:

Debus, A. G., The Chemical Philosophy, Dover Publications, 2013, p. 14–18

Medieval Medical Chemistry: The Analysis of Spa Waters

Closely assosiated with the medieval interest in transmutation was a parallel trend that led to the employment of chemical techniques in medicine. One significant area of interest was the analysis of spa waters. The importance of tests for the purity of ... 
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In the above-mentioned "De balneis et thermis naturalibus omnibus Italiae" of Savonarola, the different spa waters are presented in the You are not allowed to view links. Register or Login to view. ( including sulfur ).

Thank you bi3mw,
the book passage you linked is very interesting. I don't know much about this subject, but it seems to me that the medieval analysis of spa waters as discussed by Peter of Eboli, Giacomo de Dondi, Montagnana, Savonarola etc. was strictly scientific and quite different from the most mystical "transmutation" alchemy. If Quire13 is related to those works, it should be interpreted strictly literally, but I find it difficult to believe that all images were meant to represent actual hydraulic works. This part of the VMS could very well be related to the subject, but it would be important to understand if the authors mentioned above made use of allegories, personifications etc. It would also be interesting to find out if other manuscripts of their works in addition to Peter's De Balneis were illustrated.
Anyway, that passage is full of references that are new to me. Thank you again for sharing it!