Hi,
A very reliable source has informed me we could be looking at fake marks.
The maker's mark of the corkscrew looks like I.A under crown
in contour and indeed this particular maker's mark as such is not shown in the relevant books.
Josephus Servatius Anderlee used the following maker's mark; script letter
A in contour,
I.A under crown in oval shield,
JSA in contoured frame, this mark also has been encountered as a falsification!,
JSA in rectangle during Kingdom of Holland (1807-1812),
JSA above star in lozenge (1812-1818) and
JSA above star in square (1818/1818).
As we know the maker's mark JSA of Josephus Servatius Anderlee has been faked and perhaps this unrecorded mark I.A under crown in contour is a fake mark too. Hence the position of the dot between IA in contour, the unclear Amsterdam town mark and the half crowned O. The truth is in the mind of the beholder with knowledge.
Peter
Source:Ref:
Elias Voet, Jr., Nederlands Goud- & Zilvermerken,
Karel A. Citroen, Dutch Goldsmiths' and Silversmiths' Marks and Names prior to 1812,
Karel A. Citroen, Amsterdamse Zilversmeden en hun merken.
L.B. Gans goud-en zilvermerken van Voet.
W. Koonings De keuring van goud en zilver tijdens het Koninkrijk Holland
Waarborgholland, ˜Netherlands' Responsibility Marks since 1797
Valse Zilvermerken in Nederland K.A. Citroen
Gratitude; Premsela & Hamburger .