Crossed polarised filters
 Catalogue Number: 1134 Crossed polarised filters Category: Equipment 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. Condition: Good Location: Archive office. East wall shelves unit 3. Drawer 1 |