﻿Form 
  of 
  Pulses 
  constituting 
  Full 
  Radiation, 
  1^1 
  

  

  lY. 
  Examples 
  of 
  Records, 
  

  

  A 
  number 
  of 
  shutters 
  of 
  different 
  types 
  have 
  been 
  tested 
  

   with 
  the 
  apparatus. 
  Figs. 
  7 
  and 
  8 
  (PI. 
  XXVII.) 
  are 
  

   examples 
  of 
  the 
  records 
  obtained, 
  the 
  former 
  at 
  50 
  and 
  the 
  

   latter 
  at 
  500-^ 
  per 
  second. 
  Figs. 
  5 
  and 
  6 
  are 
  copies 
  of 
  

   records 
  obtained 
  in 
  testing 
  the 
  efficiency. 
  

  

  Fig. 
  6. 
  

  

  For 
  general 
  use 
  the 
  most 
  convenient 
  frequencies 
  to 
  work 
  

   with 
  are 
  50 
  and 
  500^- 
  per 
  second, 
  with 
  possibly 
  2000 
  for 
  

   special 
  work 
  ; 
  or 
  perhaps 
  100 
  and 
  1000^ 
  per 
  second 
  would 
  

   be 
  suitable. 
  The 
  full 
  advantages 
  that 
  the 
  method 
  offers 
  can 
  

   only 
  be 
  secured 
  by 
  the 
  use 
  of 
  round 
  numbers, 
  such 
  as 
  the 
  

   above, 
  for 
  the 
  frequencies 
  of 
  the 
  oscillations. 
  

  

  In 
  conclusion, 
  we 
  wish 
  to 
  thank 
  Dr. 
  Glazebrook 
  for 
  the 
  

   kind 
  interest 
  he 
  has 
  taken 
  in 
  the 
  working 
  out 
  of 
  the 
  method. 
  

  

  LXXXII. 
  On 
  the 
  Form 
  of 
  the 
  Pulses 
  constituting 
  Fidl 
  Radia- 
  

   tion 
  or 
  White 
  Light, 
  By 
  Albert 
  Eagle, 
  B.Sc.^ 
  A.R.CS., 
  

   Imperial 
  College 
  of 
  Science 
  and 
  TecJmologi/*, 
  \ 
  

  

  ACCORDING 
  to 
  the 
  modern 
  theory 
  of 
  White 
  Light 
  

   founded 
  by 
  Gouy, 
  and 
  subsequently 
  developed 
  by 
  

   Lord 
  Rayleigh, 
  Schuster, 
  and 
  others, 
  White 
  Light 
  does 
  

   not 
  consist 
  of 
  periodic 
  wave-trains 
  of 
  all 
  wave-lengths, 
  

   which 
  are 
  simply 
  separated 
  or 
  '' 
  dispersed 
  '^ 
  when 
  it 
  is 
  

   drawn 
  out 
  into 
  its 
  spectrum, 
  but 
  consists 
  essentially 
  of 
  a 
  

   succession 
  of 
  non-periodic 
  pulses 
  emitted 
  independently 
  of 
  

   one 
  another. 
  It 
  is 
  out 
  of 
  such 
  pulses 
  that 
  the 
  spectro- 
  

   scope 
  builds 
  up 
  the 
  periodic 
  wave-trains 
  we 
  observe 
  in 
  the 
  

   spectrum. 
  

  

  If 
  these 
  pulses 
  are 
  all 
  similar 
  and 
  follow 
  one 
  another 
  

   * 
  Communicated 
  by 
  the 
  Physical 
  Society 
  : 
  read 
  June 
  11, 
  1909. 
  

  

  