Delving into Blue(ts)

Today I have been reading about cyanometry and the cyanometer.

CYANOMETRY: The study and measurement of the blueness of light; the measurement of intensity of blue light, especially of the blue of the sky.

The cyanometer is attributed to Horace-Bénédict de Saussure (1740–99), a Swiss physicist and geologist, famous for his studies of the geology, meteorology, and botany of the mountainous regions of Europe, particularly the Alps.

The cyanometer had 53 sections, ranging from white to varying shades of blue (dyed with Prussian blue) and then to black, arranged in a circle. The color circle can be compared to any area of sky.The original instructions specified that the observer face to the north. de Saussure himself used the device to measure the color of the sky at Geneva, Chamonix and Mont Blanc. He concluded, correctly, that the color of the sky was dependent on the amount of suspended particles in the atmosphere.