342 On the Compound Line-Spectrum of Hydrogen . 



contact with powdered caustic soda, to dry it well. The 

 decomposition of the gas was effected by red-hot platinum, 

 through which the hydrogen formed was allow r ed to diffuse 

 into a vacuum. The platinum was in the form of a closed 

 tube provided with a long narrow neck, the whole being in 

 one piece, and very beautifully made for me by the further 

 kindness of Messrs. Matthey. The end of the narrow tube 

 was connected by fusion with glass tubing, and thus with the 

 spectrum-tube, pump, &c. 



In this way quite a large amount of hydrogen was diffused 

 through the platinum, three separate experiments being per- 

 formed ; but the hydrogen gave to all appearances a spectrum 

 identical with that obtained from the hydrogen absorbed by 

 palladium. I feel that particular value is attached to this 

 experiment, simple as it may seem, since great care was 

 exercised in designing the apparatus, and many precautions 

 adopted which it is impossible to detail without making the 

 description excessively long. It is perhaps sufficient to say 

 that the platinum-tube was enclosed in a glazed porcelain 

 tube, into which after evacuation the ammonia was generated; 

 the porcelain tube was heated in a specially arranged muffle- 

 furnace. 



My results, as far as they go, support therefore the 

 generally accepted conclusions that this second spectrum is a 

 true hydrogen spectrum, and render it probable that Cornu's 

 results may be explained by the fact that traces of oxygen 

 remained in his tube, such traces almost completely destroying 

 the compound spectrum. 



The above experiments were carried out in the Physical 

 Laboratories of the Owens College. 



Bibliographical List of the more recent Contributions to the 

 Knowledge of the Hydrogen Spectrum. 



[For earlier work see Tuckermann's " Index to Literature of 

 Spectroscope " (Smithsonian Institute).] 



J, S. Ames. On some Gaseous Spectra— Hydrogen. Phil. Mag. [o] 



xxx, pp. 48-56 (1890). 

 J. S. Ames. Griinwald's Mathematical Spectrum Analysis. Amer. 



Chem. Journ., Feb. 1889 ; Nature, xl. p. 19 (1889). 

 A. Grunwald. Ueber das Sogennante II. oder zusammengesetzte 



Wasserstoffspectrum von Dr. B. Hasselberg. Monatsh.fiir (Jiemie, 



iv. pp. 129-130 (1890). 

 A. Gbunwald. Ibid. Sitzungsber. d. Wien. Acad., Math.-nat. 



Klasse, II. Abtb. ci. pp. 121-2/54; Monatsh.fiir Chemie, xiii. 



pp. 111-244 (1893). 

 A, Grujn^vald. Ueber die merkwiirdigen Beziehen zwischen dem 



Spectrum des Wasserdampfes u. den linien Spectren des Wasser- 



stoffs u. Sauerstoflfe, etc. Astron. *Xac/tr. 1887, Xo. 2797, 



pp.201 214. 



