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XXXVII. The Liquefaction of Hydrogen. By Morris W. 

 Trayers, IJ.Sc, Fellow of University College, London*. 



Tlate V.] 



[Note by Prof. Ramsay. — In the course of our researches 

 on the gases of the atmosphere, it became evident that the 

 only means of separating neon in a state of purity from the 

 helium with which it was mixed, was by cooling tie mixture 

 of the two gases by aid of liquid hydrogen at its boiling- 

 point under atmospheric pressure. In order to effect this 

 separation, Dr. Trayers undertook to design and make an 

 apparatus which would produce liquid hydrogen in quantity; 

 and the following account of the experiments shows that his 

 hopes have been justified.] 



The Liquefaction of Hydrogen. 



THE experiments described in this paper were carried out 

 solely for the purpose indicated in Prof. Ramsay's 

 introductory note. The liquefaction of hydrogen has already 

 been accomplished, and my experiments differ neither in 

 principle nor in conclusions from those of Dewar. Since, 

 however, they show that the production of liquid hydrogen 

 is neither so difficult nor so costly as might have been ex- 

 pected, I have decided to publish an account of them. 



Without touching on controversial matter, the history of 

 the subject may be stated in a few words. In 1884 

 Wroblewski (Comptes Rendus, c. p. 979) showed that when 

 hydrogen, compressed into a capillary glass tube cooled to 

 the temperature of liquid oxygen, was allowed to expand 

 from 100 atmospheres to atmospheric pressure, a sudden ap- 

 pearance of mist or spray in the tube indicated that partial 

 liquefaction of the gas had taken place. In 1895 Olszewski 

 (Phil. Mag. 1895 [5] xl. p. 202) confirmed these experiments 

 by repeating them on a larger scale. Using first a glass 

 tube of 7 mm, diameter, and afterwards a steel cylinder 

 lined with glass, from which the gas escaped through a cock, 

 he found that the hydrogen remained in the liquid state for 

 a sufficient time to enable him to determine its temperature 

 by means of a platinum resistance-coil enclosed in the 

 apparatus. 



In these experiments the gas which remains in the o-lass 



tube or cylinder does work on that part of it which is escaping 



in overcoming the friction in the cock, the heat generated 



being carried away by the gas. Were the process truly 



* Communicated bv the Physical Society : re id Nov 23 1900 



2E2 ' 



