The Cyanometer helped lead to a successful conclusion that the blueness of the sky is a measure of transparency caused by the amount of water vapor in the atmosphere.
(Christopher Jobson, ‘The Cyanometer Is a 225-Year-Old Tool for Measuring the Blueness of the Sky’ Colossal)
the 53 sections of Saussure’s Cyanometer, skies over Geneva, Chamonix and Mont Blanc
21 Tue Jun 2022
Colours in Black and White 