This morning I did a few Web searches to see if anyone had mentioned the substitution/transposition code at the top of the page. I couldn't find anything, yet I think it's worthy of note partly because it's a cipher, and also because it explicitly refers to blue water and, depending on how you decipher one of the symbols, might also refer to green water.
Most of it was easy to decode, but it's only one sentence, there aren't enough letters to be 100% sure of the meaning of the sun symbol and the last word. The sun symbol is particularly important because it can completely reverse the meaning of the sentence depending on how it is interpreted. Changing one letter shifts the meaning from pleasant to unpleasant.
So, to get to the deciphering...
I am not sure whether the sun symbol (2nd line) and the over-cap sun symbol (first line) mean the same thing, or something similar, but it's possible that they stand for umlauts or abbreviations (they may also represent letters).
The parts I am sure of are as follows (in old German which can be pretty inconsistent in terms of spelling and grammar):
Diese blau wasser ist das gr_nst und der _ein war_a_ti_ __.
After deciphering the first part of the code, I realized the dark messy writing above it was also an attempt to decipher the message (I didn't notice this at first because the ink bled and the handwriting is hard to read) but decoding first and reading after made me realize that whoever deciphered it may not have been sure of a couple of the letters. For example, the word written twice at the end of the first line (first above, with a double long-s at the beginning and then below with a single long-s) was an attempt to read the last word in the line as "sein" but the "s" is already accounted for with another symbol and I see no indications that more than one glyph has been used for a single letter.
So... I don't think the assumption of "sein" is necessarily correct. It might be mein, kein, pein (or something else).
Interestingly, depending on how the partial sun symbol is interpreted, the sentence can have opposite meanings. If it stands for an umlaut and "er" then it means "cherished" and if it stands only for "er" then it would be odious or gruesome. If it is simply an umlaut, then it means "the greenest" and that's when it gets interesting... because there's a lot of blue and green water in the VMS.
So if we go with the simplest explanation for the half sun symbol (the one used as a cap in the middle of the first line), then it says:
Diese blau wasser ist das grünst und der _ein war_a_ti_ __. (This blue water is the greenest and the...)
Okay, it appears that the person deciphering the last word decoded the ending letter as an "f" (written with loops rather than a crossbar but written differently from the long-s so it doesn't appear to be an "s" and "s" is already accounted for). This doesn't make a lot of sense and it's pretty uncommon to find an "f" at the end of German words.
So, since the symbol occurs twice in the word, I have a different idea. I think it may possibly be an "h" which occurs frequently at the ends of German words and opens up more reasonable possibilities. This makes the following one possible interpretation:
Instead of
warfa_ ti_f I think it might be
warha_tich
But there's the problem of the sun symbol. Is it a modifier as it appears to have been used in the previous line? Or is it a letter?
Also, is this one word (this seems probable) or is it three? In German it can easily be broken up into war ha_ ich or war ha__ ich. I suspect it's one word since the words in the first line are written with normal spaces.
So, depending on what one substitutes for the sun symbol, and assuming the last letter might stand for "h" you can get some interesting but conflicting translations such as:
This blue water is the greenest (grünst) and my warmth (or without warmth/lacking warmth depending on which letter is in front of _ein).
This blue water is the most cherished (grüernst) and _____________________
This blue water is the most unpleasant/gruesome (gruernst) and __________________
If the sun symbol is an umlaut, modifier, or abbreviation, rather than a letter, then the last word might be something like warhätich or, if it's a letter, something like warhaltich (which is a low German word I've seen in a 19th-century book). I think there's a fairly good chance the last letter is an "h" but there are the other possibilities and I'm not a native German speaker, I don't have a crossword-puzzle vocabulary in German, so here's a snip of the last word and a list of which letters haven't yet been used in case someone has a better idea:
I don't know if the krebs symbol is one letter or two, but I suspect it's one letter and decided to go with that at least for the first run-through.
P.S., at the end of the first line, the _ein could be mein, kein, or pein (it's not an "s" as ess is already used), so whatever is substituted for the symbol for mercury in the first line cannot also be used in the last word.
Also, vis-a-vis the VMS. Since the cap over the Libra symbol is possibly an umlaut or medieval-style apostrophe (letters missing), it means at least one person in the 15th century may have used a cap shape to modify a letter, or indicate missing letters, in a cipher.