Section III, 1921 [31] Trans. R.S.C. 



On the Liquefaction of Hydrogen 



By Professor J. C. McLennan, F.R.S. 



(Read May Meeting, 1921) 



The following paper contains a short account of the method 

 which was adopted in a successful attempt recently made to liquefy 

 hydrogen in the Physical Laboratory of the University of Toronto. 



L Hydrogen 



The hydrogen used in this investigation was obtained in cylinders 

 from the National Electro Products Company, Ltd., of Toronto, and 

 was made by them electrolytically with a new type of cell which 

 they have developed for the production of hydrogen on an industrial 

 scale. Chemical tests, as well as physical ones, made by a Shakspear 

 katharometer, showed the gas as supplied in the cylinders to be of 

 over 99.5% purity. 



IL Liquid Air 



The liquid air used in the investigation was made with a 50 

 horse-power plant recently installed by the University of Toronto. 



The compressor was of the Norwalk three stage type and the 

 water cooler, the CO2 purifying columns, and the liquid air machine 

 were obtained from L'Air Liquide Co., Toronto. The Liquid Air 

 Machine was one of the Claude Oxygen-Nitrogen columns so arranged 

 as to produce liquid air or either of the gases mentioned. The 

 machine was also provided with suitable rectifying parts to extract 

 neon and helium from the air if desired. 



Repeated tests with this machine showed that with it from 600 

 to 700 pounds of liquid air could be made in twenty-four hours. 



III. Arrangement of Compressing and Purifying System 



The general arrangement for purifying the hydrogen supplied in 

 the cylinders and for compressing it prior to its admission to the 

 liquéfier is shown in Plate I. 



The hydrogen from the cylinders Ai, A2, A3 and A4 was passed 

 through a reducing valve into a 50 gallon cylinder R, provided with 



