On colour-sight and colour-blindness in its relation to railway and sea signals : read before the Glasgow Philosophical Society, on March 5, 1879 (1879)
Wolfe, J. R. (John Reisberg), 1824-1904, Royal College of Surgeons of England · London : J. & A. Churchill · leaf 13
seven different kinds of light. If we admit a beam of the sunlight through a small hole in the window-shutter of a dark room, it will go on in a straight line and form a round white spot on the wall. If we now interpose a prism whose refracting angle is such that this beam of light may fall upon… … image of the sun, containing the seven colours. This image is called the solar or prismatic spectrum. These seven colours are called primary colours, because they cannot be decomposed: pass one of B
Transportation · Color Vision Defects
Internet Archive · Royal College of Surgeons of England · Public domain (published before 1931). Free to use for anything.
