Standards of form and color-vision required in railway service (1897)
Williams, Charles H. (Charles Herbert), 1850-1918, author, American Ophthalmological Society · leaf 14
16 … FIG. I. Back view of Williams’ apparatus for testing color-vision, showing the position of the lantern and the discs of colored glass. The colored glasses are held in place in cells made between two wooden discs, which are clamped together and can be revolved at the back of the instrument so as to…
Color Vision Defects · Mandatory Testing · Railroads
Internet Archive · U.S. National Library of Medicine · Public domain (published before 1931). Free to use for anything.
