﻿344 
  Messrs. 
  J. 
  N. 
  Lockyer 
  and 
  W. 
  C. 
  Roberts 
  [Mar. 
  18, 
  

  

  II. 
  " 
  On 
  the 
  Absorption-Spectra 
  of 
  Metals 
  volatilized 
  by 
  tbe 
  

   Oxyhydrogen 
  Flame." 
  By 
  J. 
  Norman 
  Lockyer, 
  F.R.S., 
  and 
  

   W. 
  Chandler 
  Roberts, 
  Chemist 
  of 
  the 
  Mint. 
  Received 
  

   February 
  4, 
  1875. 
  

  

  The 
  researches 
  which 
  have 
  recently 
  been 
  published 
  on 
  the 
  absorption- 
  

   spectra 
  of 
  various 
  metals, 
  first 
  by 
  Roscoe 
  aud 
  Schuster 
  aud 
  subsequently 
  

   by 
  one 
  of 
  us 
  *, 
  establish 
  beyond 
  all 
  question 
  the 
  facts 
  that 
  — 
  

  

  I. 
  In 
  addition 
  to 
  the 
  well-known 
  hue-spectra, 
  channelled-space 
  spectra 
  

   are 
  produced 
  by 
  the 
  vapours 
  of 
  certain 
  metals 
  ; 
  and, 
  

  

  II. 
  Such 
  spectra 
  are 
  produced 
  by 
  vapours 
  which 
  are 
  competent 
  to 
  give 
  

   at 
  other 
  times, 
  not 
  only 
  line-spectra, 
  but 
  continuous 
  spectra 
  in 
  the 
  

   blue, 
  or 
  blue 
  and 
  red. 
  

  

  As 
  the 
  temperature 
  employed 
  for 
  the 
  volatilization 
  of 
  the 
  metals 
  in 
  the 
  

   experiments 
  to 
  which 
  we 
  have 
  referred 
  did 
  not 
  exceed 
  bright 
  redness, 
  or 
  

   that 
  at 
  which 
  cast 
  iron 
  readily 
  melts, 
  the 
  range 
  of 
  metals 
  examined 
  was 
  

   necessarily 
  limited. 
  We 
  have 
  therefore 
  considered 
  it 
  desirable 
  to 
  extend 
  

   these 
  observations 
  to 
  the 
  less 
  fusible 
  metals, 
  as 
  well 
  as 
  to 
  ascertain 
  

   whether 
  the 
  spectra 
  of 
  those 
  which 
  were 
  volatilized 
  at 
  the 
  lower 
  tempera- 
  

   ture 
  would 
  be 
  modified 
  by 
  the 
  application 
  of 
  a 
  greater 
  degree 
  of 
  heat. 
  For 
  

   this 
  purpose 
  we 
  have 
  employed 
  the 
  flame 
  of 
  an 
  oxyhydrogen 
  blowpipe. 
  

   This 
  instrument, 
  devised 
  by 
  Sainte-Claire 
  Deville 
  and 
  Debrayf 
  , 
  renders 
  

   it 
  possible 
  to 
  attain 
  high 
  temperatures 
  with 
  great 
  facility, 
  and 
  Stas 
  has 
  

   already 
  employed 
  their 
  method 
  in 
  the 
  distillation 
  of 
  silverj. 
  The 
  lime 
  

   still 
  arranged 
  by 
  him 
  has 
  been 
  modified 
  in 
  that 
  about 
  to 
  be 
  described, 
  in 
  

   order 
  that 
  the 
  metallic 
  vapour 
  might 
  be 
  conducted 
  into 
  a 
  lime 
  tube 
  or 
  

   tunnel 
  heated 
  to 
  whiteness, 
  so 
  placed 
  that 
  a 
  beam 
  from 
  an 
  electric 
  lamp 
  

   could 
  readily 
  traverse 
  it. 
  

  

  Description 
  of 
  the 
  Apparatus 
  and 
  method 
  of 
  Manipulation. 
  

  

  The 
  apparatus 
  employed 
  is 
  shown 
  in 
  the 
  figure, 
  in 
  which 
  A 
  is 
  the 
  

   block 
  of 
  lime 
  § 
  divided 
  horizontally 
  by 
  a 
  plane 
  through 
  the 
  axis 
  of 
  the 
  

   tube 
  (B 
  B'), 
  this 
  tube 
  being 
  16 
  centims. 
  long 
  and 
  30 
  millims. 
  diameter. 
  

   The 
  receptacle 
  (C) 
  communicates 
  with 
  the 
  centre 
  of 
  B 
  B', 
  and 
  is 
  open 
  at 
  

   the 
  upper 
  surface 
  of 
  the 
  lime 
  block, 
  in 
  order 
  to 
  admit 
  of 
  the 
  introduc- 
  

   tion 
  of 
  the 
  oxyhydrogen 
  blowpipe 
  (D), 
  which 
  is 
  provided 
  with 
  a 
  thick 
  

   nozzle 
  of 
  platinum 
  20 
  millirus. 
  in 
  diameter. 
  The 
  ends 
  of 
  the 
  tunnel 
  in 
  

   the 
  lime 
  were 
  closed 
  by 
  glass 
  plates 
  held 
  on 
  by 
  a 
  suitable 
  clip. 
  Small 
  

  

  * 
  Proc. 
  Boy. 
  Soc. 
  vol. 
  xxii. 
  pp. 
  362 
  and 
  371 
  respectively, 
  

   t 
  Ann. 
  de 
  Chimie 
  et 
  de 
  Physique, 
  torn. 
  lvi. 
  p. 
  413. 
  

   I 
  Stas, 
  ' 
  Sur 
  les 
  lois 
  des 
  proportions 
  Chimiques,' 
  p. 
  56. 
  

  

  § 
  We 
  are 
  indebted 
  to 
  the 
  well-known 
  metallurgist, 
  Mr. 
  J. 
  S. 
  Sellon, 
  of 
  the 
  firm 
  of 
  

   Johnson 
  and 
  Matthey, 
  for 
  a 
  pure 
  variety 
  of 
  limestone 
  from 
  which 
  the 
  blocks 
  were 
  pre- 
  

   pared, 
  and 
  it 
  answered 
  its 
  purpose 
  admirably. 
  

  

  