﻿the 
  Source 
  of 
  the 
  x-Rays. 
  187 
  

  

  Photographic 
  plates 
  were 
  exposed 
  opposite 
  to 
  the 
  thin 
  bulb 
  

   on 
  the 
  straight-wire 
  tube. 
  These 
  plates 
  were 
  carefully 
  insu- 
  

   lated 
  from 
  the 
  ground, 
  and 
  were 
  covered 
  in 
  one 
  case 
  with 
  a 
  

   sheet 
  of 
  hard 
  rubber 
  ^ 
  of 
  an 
  inch 
  in 
  thickness, 
  and 
  in 
  another 
  

   case 
  by 
  a 
  sheet 
  of 
  glass 
  about 
  \ 
  an 
  inch 
  in 
  thickness. 
  A 
  

   powerful 
  brush-discharge 
  was 
  seen 
  in 
  the 
  dark 
  room 
  to 
  pass 
  

   from 
  the 
  thin 
  bulb 
  of 
  the 
  tube 
  to 
  the 
  insulator 
  which 
  covered 
  

   the 
  plates 
  ; 
  and 
  on 
  developing 
  the 
  plates, 
  they 
  were 
  found 
  to 
  

   be 
  covered 
  with 
  star-like 
  clusters 
  surrounded 
  by 
  nebulous 
  

   patches. 
  It 
  was 
  evident 
  that 
  the 
  brush-discharge 
  had 
  pro- 
  

   duced 
  discharges 
  at 
  the 
  surface 
  of 
  the 
  dry 
  plates, 
  even 
  through 
  

   plates 
  of 
  glass 
  -J 
  an 
  inch 
  in 
  thickness. 
  Moreover, 
  there 
  was 
  a 
  

   general 
  darkening 
  of 
  the 
  surface 
  of 
  the 
  plate 
  which 
  indicated 
  

   the 
  action 
  of 
  #-rays. 
  No 
  metallic 
  objects 
  could 
  be 
  placed 
  

   upon 
  the 
  dry 
  plates, 
  for 
  a 
  powerful 
  spark 
  immediately 
  passed 
  

   to 
  them 
  and 
  punctured 
  the 
  tubes. 
  The 
  darkening, 
  however, 
  

   was 
  apparently 
  diminished 
  under 
  strips 
  of 
  glass, 
  although 
  the 
  

   effect 
  of 
  the 
  brush-discharge 
  masked 
  the 
  effect 
  of 
  the 
  x-rays. 
  

   Before 
  the 
  straight 
  tube 
  was 
  exhausted 
  powerful 
  brush- 
  

   discharges 
  were 
  given 
  off 
  at 
  the 
  ends 
  of 
  the 
  tube. 
  When 
  

   the 
  tube 
  was 
  exhausted, 
  these 
  brushes 
  were 
  much 
  diminished, 
  

   and 
  were 
  replaced 
  by 
  a 
  powerful 
  brush 
  which 
  came 
  off 
  from 
  

   the 
  straight 
  wire 
  through 
  the 
  thin 
  bulb 
  of 
  the 
  tube, 
  and 
  

   speedily 
  punctured 
  the 
  latter 
  when 
  any 
  object, 
  even 
  an 
  

   insulator, 
  was 
  brought 
  within 
  six 
  inches 
  of 
  the 
  bulb. 
  The 
  

   most 
  inter 
  estin 
  or 
  result 
  obtained 
  with 
  this 
  form 
  of 
  tube 
  was 
  

   the 
  production 
  of 
  the 
  so-called 
  ^-ray 
  burn, 
  by 
  means 
  of 
  the 
  

   brush- 
  discharge 
  from 
  its 
  bulb. 
  When 
  the 
  back 
  of 
  the 
  hand 
  

   was 
  exposed 
  to 
  the 
  brush-discharge, 
  which 
  assumed 
  a 
  peculiar 
  

   forked 
  nature 
  in 
  the 
  dark 
  room, 
  a 
  peculiar 
  prickling 
  sensation 
  

   was 
  experienced, 
  and 
  all 
  the 
  symptoms 
  of 
  the 
  well-known 
  x-raj 
  

   burn 
  developed. 
  The 
  skin, 
  when 
  examined 
  under 
  a 
  micro- 
  

   scope, 
  exhibited 
  an 
  appearance 
  similar 
  to 
  that 
  shown 
  by 
  the 
  

   photographic 
  plate. 
  There 
  were 
  centres 
  of 
  inflammation 
  

   surrounded 
  by 
  regions 
  of 
  lesser 
  degrees 
  of 
  burn. 
  It 
  seems 
  

   evident 
  that 
  the 
  so-called 
  x-ray 
  burn 
  is 
  due 
  to 
  an 
  electri- 
  

   fication 
  — 
  a 
  discharge 
  at 
  the 
  surface 
  of 
  the 
  skin 
  — 
  and 
  this 
  

   electrification 
  may 
  or 
  may 
  not 
  be 
  accompanied 
  by 
  the 
  ^-rays. 
  

   This 
  first 
  form 
  of 
  tube 
  was 
  then 
  abandoned, 
  and 
  a 
  straight- 
  

   wire 
  tube 
  alone 
  (fig. 
  2) 
  was 
  employed. 
  Similar 
  results 
  were 
  

   obtained 
  with 
  this 
  tube. 
  It 
  was 
  significant 
  that 
  the 
  whole 
  

   interior 
  of 
  this 
  tube 
  fluoresced 
  brilliantly 
  when 
  it 
  formed 
  part 
  

   of 
  a 
  circuit 
  through 
  which 
  a 
  disruptive 
  discharge 
  passed. 
  

   This 
  latter 
  form 
  of 
  tube 
  was 
  replaced 
  by 
  the 
  form 
  represented 
  

   in 
  fig. 
  3. 
  A 
  side 
  tube 
  ending 
  in 
  a 
  thin 
  bulb 
  w 
  r 
  as 
  added 
  to 
  the 
  

   straight-wdre 
  tube. 
  The 
  same 
  phenomenon 
  was 
  exhibited 
  by 
  this 
  

  

  