OPTICAL CORNING U.S. PATT. OCT 10 1925 3 1/2 3 1/2
Front: Green Glass.
special note . Oct 10 1925, while on some lenses that cast the latest version of a pattern and they themselves in some castings will show variations in how they cast that information either 10-10-05 or Oct 10 1905 .
The date of "1925" might be an error .
Mold making does in fact show degrees of errors relating to punch numbers and letters in early lenses ..
ADDED 1/10/21 This FSO measures 5 3/8 dia.
OPTICAL CORNING U.S. PATT. OCT 10 1925 3 1/2 3 1/2
Front: Green Glass.
special note . Oct 10 1925, while on some lenses that cast the latest version of a pattern and they themselves in some castings will show variations in how they cast that information either 10-10-05 or Oct 10 1905 .
The date of "1925" might be an error .
Mold making does in fact show degrees of errors relating to punch numbers and letters in early lenses ..
ADDED 1/10/21 This FSO measures 5 3/8 dia.