Raoul Pierre Pictet (4.04.1846-27.07.1929) — a Swiss physicist. He was born in Geneva. He studied (1868-70) in Geneva and Paris. In 1870 he returned to Geneva and took up experiments in low-temperature physics. In 1879-86 he headed a chair at the University of Geneva. In 1886 he founded an industrial research laboratory in Berlin. He then lived in Paris.
His research was on the liquefaction of gases and the study of low-temperature phenomena. He developed the “cascade” method of liquefying gases and, almost simultaneously with the French engineer L. Cailletet, was the first to obtain (1877) liquid oxygen, at a pressure of 320 atm and a temperature of —140 °C, reached with the use of sulfurous and carbonic acids. He later liquefied air, nitrogen, hydrogen and carbon dioxide as well. He worked on the creation of refrigeration systems.
His research was on the liquefaction of gases and the study of low-temperature phenomena. He developed the “cascade” method of liquefying gases and, almost simultaneously with the French engineer L. Cailletet, was the first to obtain (1877) liquid oxygen, at a pressure of 320 atm and a temperature of —140 °C, reached with the use of sulfurous and carbonic acids. He later liquefied air, nitrogen, hydrogen and carbon dioxide as well. He worked on the creation of refrigeration systems.