Cyanometer

Rarity: Common

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At a glance

Class

Notion

Domain

Science and technology

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What Wikipedia says

A cyanometer (from cyan and -meter) is an instrument for measuring "blueness", specifically the colour intensity of blue sky. It is attributed to Horace-Bénédict de Saussure and Alexander von Humboldt.

Excerpt from the Wikipedia article “Cyanometer”, under the CC BY-SA 4.0 license. Read the article on Wikipedia

Image: Horace-Bénédict de Saussure, CC BY-SA 4.0, via Wikimedia Commons.