Synoptophore possibly invented by Walter Green
1931-1940
Six card holders for use with synoptophore
Synoptophore by Clement Clarke Ltd.
1929-1936
Synoptophore by Clement Clarke Ltd.
1929-1940
Synoptophore, possibly invented by Walter Green
1931-1940
Synoptophore by Clement Clarke Ltd.
1929-1940
Green synoptophore
Box of glass slides for use in synoptophore
Synoptophore, English, 1930-1950
1930-1950
Two Sharp Crawford rotating slide holders for use with synoptophore
Two Sharp Crawford rotating slide holders with slides
Two boxes of glass synoptophores
Synoptophore by Clement Clarke Ltd.
1930-1940