﻿Phil. 
  Mag. 
  Ser. 
  6, 
  Tol. 
  26, 
  PI. 
  XIY. 
  

  

  yen 
  Spectrum. 
  (Water 
  Vapour 
  present.) 
  

  

  I 
  visible 
  

  

  Spectrometer 
  Read/ng. 
  

   , 
  — 
  The 
  Hydrogen 
  Spectrum. 
  

  

  40 
  

   \LLI-flMP 
  

  

  59° 
  

   <[CTROMETLR 
  Re/IUINC 
  

  

  of 
  Air 
  (contaminated 
  with 
  Hydrogen). 
  

  

  