It's not Alchemy from Jeremy Tankard... I'm curious on this ID 
Margo Chase 's Edit?
http://www.t26.com/fonts/display.php?f_id=443
no sorry Margo Chase 's Shiraz?
http://www.t26.com/fonts/display.php?f_id=449&dw=1943
How about the "ch" ligature from DTL Fleischmann italic?
You probably know this, Mr. Hudson, but here's a brief origin of the percent sign. (not sure how credible that info is)
I guess Mr. Storm used a little creative license. Perhaps the "c" is for "centum."
No, I think you're right. In the roman font there's a standard percent symbol, but I guess he intended for the italic to be used as "care of." How about that...
At MyFonts.com: Jannon Antiqua Italic percent
You're right, that's pretty amazing. Concerning the "care of" sign that Mr. Hudson mentioned above, I'd like to know if that's what Storm intended.
I came across the percent sign while looking at Moderne Antique Italic in TypeTool. I haven't seen it anywhere else.
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