﻿1875.] 
  on 
  the 
  Absorption-Spectra 
  of 
  Metals. 
  347 
  

  

  Aluminium. 
  

  

  When 
  the 
  temperature 
  was 
  so 
  high 
  that 
  the 
  spectrum 
  of 
  the 
  flame 
  was 
  

   visible, 
  an 
  absorption 
  was 
  suspected 
  in 
  the 
  violet 
  ; 
  and 
  the 
  appearance 
  

   did 
  not 
  change 
  on 
  one 
  glass 
  end 
  being 
  removed. 
  

  

  Zinc. 
  

  

  Many 
  experiments 
  were 
  made 
  on 
  this 
  metal; 
  but 
  there 
  are 
  several 
  

   points 
  connected 
  with 
  it 
  which 
  require 
  further 
  investigation, 
  and 
  we 
  

   therefore 
  reserve 
  our 
  remarks 
  on 
  the 
  spectrum 
  of 
  zinc 
  for 
  a 
  future 
  

   occasion. 
  

  

  Cadmium. 
  

  

  Under 
  both 
  conditions 
  of 
  thickness 
  the 
  vapour 
  of 
  cadmium 
  gave, 
  in 
  

   the 
  blue 
  only, 
  an 
  absorption 
  which 
  was 
  very 
  decided 
  ; 
  an 
  absorption 
  in 
  

   the 
  red 
  was 
  also 
  noticed 
  which 
  had 
  not 
  been 
  observed 
  in 
  previous 
  experi- 
  

   ments 
  when 
  a 
  low 
  temperature 
  was 
  employed. 
  

  

  Manganese. 
  

  

  A 
  small 
  quantity 
  of 
  this 
  metal 
  was 
  prepared 
  with 
  great 
  care 
  by 
  Mr. 
  

   Bayly, 
  one 
  of 
  the 
  assistant 
  assayers, 
  and 
  it 
  gave 
  a 
  distinct 
  absorption 
  

   in 
  the 
  red 
  and 
  blue, 
  with 
  evidences 
  of 
  a 
  channelled-space 
  spectrum. 
  In 
  

   a 
  repetition 
  of 
  the 
  experiment 
  a 
  more 
  distinct 
  channelled-space 
  spectrum 
  

   was 
  observed. 
  

  

  Iron. 
  

  

  The 
  metal 
  employed 
  had 
  been 
  obtained 
  by 
  electro-deposition 
  in 
  the 
  

   manner 
  suggested 
  by 
  Mr. 
  Jacobi. 
  Its 
  vapour 
  gave 
  a 
  slight 
  continuous 
  

   absorption 
  in 
  the 
  blue. 
  

  

  Cobalt 
  

  

  also 
  gave 
  a 
  slight 
  continuous 
  absorption 
  in 
  the 
  blue, 
  but 
  less 
  than 
  in 
  

   the 
  case 
  of 
  iron. 
  

  

  Nickel. 
  

  

  This 
  metal 
  behaved 
  in 
  the 
  same 
  manner 
  as 
  cobalt, 
  the 
  absorption 
  being 
  

   about 
  equal 
  in 
  amount. 
  

  

  Chromium. 
  

  

  The 
  amount 
  of 
  metal 
  volatilized 
  was 
  very 
  small, 
  but 
  a 
  fine 
  channelled- 
  

   space 
  spectrum 
  was 
  observed. 
  

  

  Tin. 
  

  

  This 
  metal 
  caused 
  a 
  considerable 
  absorption 
  in 
  the 
  blue, 
  but 
  less 
  in 
  

   the 
  red, 
  no 
  traces 
  of 
  a 
  channelled-space 
  spectrum 
  being 
  visible. 
  

  

  Antimony. 
  

  

  In 
  results 
  already 
  published 
  it 
  is 
  stated 
  that 
  at 
  the 
  low 
  temperature 
  

   antimony 
  gives 
  a 
  channelled-space 
  spectrum. 
  In 
  the 
  present 
  experi- 
  

  

  2d2 
  

  

  