Physical description
Test plate rectangular glass slide with rulings under circular cover glass within yellow circle and brown border enclosed in red hinged box with blue lining. Described as “A sample Microscope slide - Test plate with rulings from 30,000 to 120,000 per inch”. This is the only surviving ruling reaching up to 120,000; hence is both unique and valuable.
Inscriptions & markings
Labels on slide: “Test plate 10,000 to 120,000. Ruled by H.J. Grayson, Melbourne”. No of lines per inch Band 1-10,000 2-20,000”. On label on side: “No of lines per inch Band 3 -30,000 4 - 40,000 5-50,000 6-60,000 7-70,000 8-80,000 9-90,000 10-100,000 11-110,000 12-120,000”
