A KNAPP OPHTHALMOTROPE
GERMAN, LATE 19TH CENTURY
with maker's or retailer's label Fritz Salan Halbersdadt Rathenow Berlin Wien, the two eyes rigged with six strings each attached to weights behind the backplate, supported on tripod foot
15½in. (39cm.) high
A KNAPP OPHTHALMOTROPE
GERMAN, LATE 19TH CENTURY
with maker's or retailer's label Fritz Salan Halbersdadt Rathenow Berlin Wien, the two eyes rigged with six strings each attached to weights behind the backplate, supported on tripod foot
15½in. (39cm.) high