by Inigo del Castillo in Tech on Tuesday 13 May 2014

How many shades of blue does the sky have? If this 225-year old measuring tool is to be believed, the sky has 53 shades of ‘blueness’. The Cyanometer is a device invented back in 1789 by Swiss physicist Horace-Benedict de Saussure and German naturalist Alexander von Humboldt.

It was meant to measure the ‘blueness’ of the sky, specifically the colour intensity. To make the device, Saussure dyed squares of paper to ever possible shade of blue he could identify. These were then arranged into a circle, to which he could hold up and compare the sky’s colour.

Using the Cyanometer, De Saussure was able to derive that the sky’s blueness relied on the amount of water vapour in the atmosphere.

Via This Is Colossal