In Glass cone #24 there is a question raised over a painted propeller mark.
Hartmann, Glasmarken Lexikon, attributes this propeller mark to Gräflich Harrach'sche Glasfabrik and gives Hajdamach British Glass 1800-1814 as the source of attribution, however on page 450 of that book it is only referred to as probably Bohemian.
There is nothing in the index to suggest the mark is discussed elsewhere in the book, so an odd discrepancy. My email for Hajdamach is bouncing if anyone has a current one, please advise by email. Of course a contact with Hartmann would be useful too.