Goodevening,
I'd like to have some more information about the postmark named Kaminstempel: it is interesting and unusual because of the shape unknown in the Austrian Empire. I didn't find it in the Muller's handbook of prephilatelic marks. Also in the italian territories we don't have the same: only in Milano there is a mark looking like it used on arrival on registered letter. I post it below.
What does the german philatelic literature write about it? What do collectors think about its origin?
Thanks for any your help
Francesco