Notes

Abstract

THE scientific world has lost one of its veterans by the death of Louis Paul Cailletet in Paris on January 5. Born in 1832, at Chatillon-sur-Seine, he studied at the School of Mines and the Faculty of Sciences at Paris. His first work was in metallurgy, and he made many scientific investigations into the principles of cementation and puddling. Later work on the theory of smelting led him to investigate the properties of gases under pressure. As a result of an admirable series of researches he was able to announce in 1877 that he had liquefied oxygen by cooling produced by sudden release from considerable pressure. The same result was obtained by Pictet at Geneva in the same year by a different method, and quite independently. Later investigations enabled all the so-called permanent gases to be liquefied with the exception of hydrogen, which was left for Wroblewsky, who had been his pupil, and much of the later work of Amagat, Dewar, Kamerlingh Onnes, Linde, and Claude was the direct result of his methods and discoveries. In conjunction with Mathias, investigations on vapour pressures and critical volumes led to the discovery of the law of the rectilinear diameter, which has had such fruitful results. Always devoted to scientific work, he became much interested in aviation, acting for many years as the president of the Aero Club of France. The Academy of Sciences elected him a corresponding member in 1877, and gave him the Jecker prize and elected him an academician in 1884. In 191o, on the occasion of his academic jubilee, he was proclaimed the father of modern cryogenics.