MORE ON THE DISCOVERIES CONCERNING EGYPTIAN HIEROGLYPHICS by a medieval Arab alchemist: Carla Sulzbach e-mails to point me to a message by Lennart Sundelin on the ANE list. Key paragraph:

Unfortunately it [the Kitab Shawq al-Mustaham] was not produced by someone who could actually read hieroglyphics. The Hermetic lore that this work was based on was circulating in Europe, too, long before Champollion, and it was an approach that long proved a dead-end for those trying to 'crack the code'. I think we're still stuck with Champollion and the Rosetta Stone. Alas!

You can find the 1806 English translation of the Arabic work (along with the Arabic original) here and decide for yourself. As Carla points out in her e-mail, whatever the accomplishment of Abu Bakr Ahmad Ibn Wahshiyah, it's important to keep in perspective that there was no follow-up and the hieroglyphics were not actually deciphered before Champollion.

It's an interesting episode in intellectual history, but my "extraordinary discovery" below was an overstatement. The Observer article overplays the story too. The article in the Daily Times is more measured.