Specimen glass tints for signal spectacles

Specimen glass tints for signal spectacles; three pieces of coloured glass in wooden case; blue labelled "Standard Tints - Mr Ross's letter of April 6th 1915"; used for testing the tints of signal spectacles

Details

Category:
Signalling & Telecommunications
Object Number:
1978-8440
type:
glass
credit:
British Rail, Clapham