Color-vision and color blindness, a practical manual for railroad surgeons (1920)
Jennings, John Ellis · Philadelphia F.A. Davis · leaf 80
composed of li<>liter and darkershades of rose alternating with bines, etc. Tlie thirdseries, from 31 to 40, is made up of reds alternatingwith browns, sages, and dark olives. In making an examination the candidate is re-qnested to select ten tints from the worsteds on the stickto match the… … FiG. 15.—Thomsons Stick. blind, the mingling of even numbers betrays his defectat a glance. In order to determine whether the defectis for red or green, tlie candidate is required to matchthe rose sample. The red-blind selects indifferently theroses and blues between 20 and 30, while the…
Color-blindness · Eye
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