Thanks for asking, Oliver :-) Zantke's list of Frodsham numbers only begins with 1878. The more recent book by Paul Audemars, The Story of Louis Audemars & Cie, contains additional ledgers and serial numbers that weren't available to Zantke when he pu
research. " This timepiece, with it's Frodsham number, appears in the registers of LB Audemars; made available by Hartmut Zantke in his substantial book "Louis-Benjamin Audemars His Life and Work" I have the book you mentioned ... ... and I tried to find