>One thing that I have difficulty with, for example, is that the modern
>Icelandic pronounciation of "æ" (= a-e ligature) no longer corresponds
>to the way this letter was pronounced in Medieval Latin, where it was
>known from such words as "Cæsar" etc. I am sure the monks who first
>used the Latin letters to describe the sounds of Old Norse, did pick
>the Latin letters that corresponded most closely to the actual sounds
>used!

>Thus we can expect that the Old Norse "æ" was prononced in approximately
>the same way as the "æ" in Cæsar was pronounced.

An interesting thing seems to have happened with the æ-sound:

Old Latin [ai] Late Latin [E:]
Old Icelandic [E:] Late Icelandic [ai]

How would you write this in chemistry; Keth?

[ai] <--> [E:]

Regards,
Haukur