Catalogue Number: 1134
Crossed polarised filters
Sub-Category: PD ruler, pupillometer
Time Period: 1940 to 1999
Description Of Item: Pair of crossed polarised filters in spring 'tong grip' mounting.Metal, glass, cork L: 15.0 cm x W: 2.7 cm x D: 2.9 cm
Historical Significance: This instrument was used to check toughening of glass spectacle lenses.
Location: Archive office. East wall shelves unit 3. Drawer 1