Re: Strange Sign
Lead carbonate is, and has always been, more expensive than flour.
You're probably right - it was the first thing that came to my mind. The principle stands though, in the absence of regulation all sorts of things were added to foodstuffs:
Adulteration of Food. (see also link at the bottom of that page)
Here's a Punch cartoon:
Oh, and 'lead' isn't a proper noun.
Isn't it? Isn't Lead an element alongside Copper and Oxygen and Hydrogen and Neon and all the other things we usually capitalise? (Well, I usually capitalise, anyway)
M.