|Born||4 April 1846
|Died||27 July 1929
|Institutions||University of Geneva|
|Known for||Liquid nitrogen|
Raoul-Pierre Pictet (4 April 1846 – 27 July 1929) was a Swiss physicist and the first person to liquefy nitrogen. He was born in Geneva and served as professor in the university of that city. He devoted himself largely to problems involving the production of low temperatures and the liquefaction and solidification of gases.
On December 22, 1877, the Academy of Sciences in Paris received a telegram from Pictet in Geneva reading as follows: Oxygen liquefied to-day under 320 atmospheres and 140 degrees of cold by combined use of sulfurous and carbonic acid. This announcement was almost simultaneous with that of Cailletet who had liquefied oxygen by a completely different process.
Pictet is the author of Mémoire sur la liquéfaction de l'oxygène, la liquéfaction et la solidifaction de l'hydrogène et sur les théories des changements des corps (1878); Synthèse de la chaleur (1879); Nouvelles machines frigorifiques basées sur l'emploi de phénomènen physicochimiques (1895); Etude critique du matérialisme et du spiritualisme par la physique expérimentale (1896); L'Acétylène (1896); Le carbide (1896); Zur mechanischen Theorie der Explosivstoffe (1902); Die Theorie der Apparate zur Herstellung flüssiger Luft mit Entspannung (1903).
Pictet died in Paris in 1929.
•Pictet’s apparatus • Production of oxygen under pressure in a retort. Two pre-cooling refrigeration cycles:
1. first stage SO2(-10°C) 2. second stage CO2(-78°C) oxygen flow is pre –cooled by the Means of heat exchangers and Expands to atmosphere via a Hand valve
- For biographical details, see Sloan, T. O'Connor (1920). Liquid Air and the Liquefaction of Gases. New York: Norman W. Henley. pp. 152–171.
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