Herschel discovers infrared light. Ritter discovers ultraviolet light. Young proposes three receptor theory of colour vision and introduces mapping of visual fields. Young discovers interference. 1804 Troxler describes loss of colour in the periphery of the visual field.
Gall proposes concept of localisation of mental functions in the cortex.
1808 French Academy refuses to admit Gall on grounds that the cortex has nothing to do with thinking. Young proposes transverse wave model of light. 1818 Vieth-Muller horopter. Wollaston explains homonymous hemianopia in terms of partial decussation at the chiasm. Niepce makes the first photograph.