1789 in science

thumb|right|A cyanometer by Horace-Bénédict de Saussure (from the collection of ''Musée d'histoire des sciences de la Ville de Genève) thumb|right|An artwork in Ljubljana, Slovenia, inspired by a cyanometer 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. It consists of squares of paper dyed in graduated shades of blue and arranged in a color circle or square that can be held up and compared to the color of the sky.

overview of natural science-related events during the year of 1789