THE CRYOGENIC LABORATORY AT LEIDEN ^ 



I 



By ROBEBT GUILLIEN 



Former pupil of L'Ecole Normale Sup6rieure, Agrdg4 de VUniversiU ; at present 

 at L'Institut Francais (V Amsterdam 



[With 5 plates] 

 INTRODUCTION 



In 1882 Kamerlingli Onnes was appointed professor and director 

 of the physical laboratory of the University of Leiden. Two years 

 previously Van der Waals had deduced from his equation the law 

 of corresponding states. Kamerlingh Onnes undertook to verify 

 this law which he himself had also found from considerations of 

 similitude. Realizing that for substances liquid at ordinary tem- 

 peratures there is often decomposition at temperatures below the 

 critical point, Kamerlingh Onnes preferred to deal with substanc-^s 

 which are gaseous at ordinary temperatures. He proposed to refrig- 

 erate and liquefy these gases. For measurements on their equations 

 of state as liquids, it is necessary to produce very low temperatures 

 and maintain them constant. 



Also by a happy intuition, Kamerlingh Onnes conceived that at 

 low temperatures the properties of bodies should obey more simple 

 laws and be easier to interpret than the laws of bodies at ordinary 

 temperatures. He therefore desired not only on the one hand to 

 study the properties of liquids at low temperatures, but on the other 

 to obtain low temperatures in order to be able to investigate the 

 properties of substances in general. 



The laboratory had at the start the cycle of methyl chloride, and 

 then the cycle of liquid ethylene, condensed under pressure after 

 cooling with methyl chloride. This led to the liquefaction of oxygen 

 in 1894 by means of preliminary cooling under compression and 

 refrigeration by liquid ethylene. The liquefaction of hydrogen was 

 then attempted, but this time by the method of Linde. In 1906 the 

 first measurements were made in a bath of liquid hydrogen. Going 

 still further, Kamerlingh Onnes succeeded in 1908 in liquefying 



^Translated by permission from Revue G6n6rale des Sciences, toI. 47, no. 4, Feb. 29, 

 1936, 



177 



