I would have included this example, had I been organized enough to know that I had it at the time . . .
and educated enough to know what that WL-ish looking hallmark meant . . .
In fact, if I’d researched this one first, the Ludden connection would have been much more straightforward to find, because the patent date on this one, October 17, 1871, is a correct and direct reference to a William Ludden patent I didn’t mention in my previous articles, number 119,935, for a fairly conventional magic pencil: