Well this has been interesting, first I had to look up "mitherin" but I did get the crapper cover, somewhere I have a book titled "Flushed with Pride, the story of Thomas Crapper, Royal Plumber" not sure if it's a true historic document but at least there were documented cast iron manhole covers at one point in the London sewer system with the "Crapper" name cast on them. A good read when in the littlest room.
Kristin