How blue is the sky? Horace Bénédict de Saussure's CYANOMETER, 1789. For his weather observations, to measure "blueness" he used suspensions of Prussian blue, dying paper squares every shade of blue he could distinguish between white and black. These were assembled into a numbered colour circle that could be held up to the zenith at a standard distance from the eye - the matching square established the degree of blue. (The color of the atmosphere indicates particles and water vapour in the air.) Shades, Blue Sky, Pattern Tattoo, Tattoo Pattern, Blue Room, Colors Wheels, Colours Wheels, Tattoo Design, Design Tattoo
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Horace-Bénédict de Saussure’s Cyanometer ~ An 18th century instrument for measuring the blueness of the sky.