Liveing and Dewar — Separation of the Gases, etc. 207 



Art. XXIY. — On the Separation of the Least Volatile Gases 

 of Atmospheric Air, and their Spectra / by G-. D. Liveing, 

 H.A., Sc.D., F.R.S., Professor of Chemistry in the Uni- 

 versity of Cambridge, and James Dewar, M.A., LL.D., 

 F.R.S., Fullerian Professor of Chemistry, Royal Institution, 

 London. 



[Read before the Royal Society of London, June 20, 1901.] 



Our last communication to the Society* related to the most 

 volatile of the atmospheric gases; that which we now beg 

 leave to offer relates to the least volatile of those gases. The 

 former were obtained from their solution in liquid air by frac- 



Topump 



\g) ^jj 



tional distillation at low pressure, and separation of the con- 

 densible part of the distillate by cooling it in liquid hydrogen. 

 The latter were, in the first instance, obtained from the residue 

 of liquid air, after the distillation of the first fraction, by 

 allowing it to evaporate gradually at a temperature rising only 

 very slowl} 7 . The diagram, fig. 1, will make the former 

 process intelligible. A represents a vacuum-jacketed vessel, 

 partly filled with liquid air, in which a second vessel, B, was 

 immersed. From the bottom of B a tube, a, passed up 



* Proc. Roy. Soc., vol. lxvii, p. 467 : this Journal, xi, 154. 



Am. Jour. Scl— Fourth Series, Vol. XT, No. 69. 

 15 



-September, 1901. 



