﻿Prof. 
  A. 
  Tvoiti 
  on 
  the 
  x-Rays 
  and 
  the 
  Cathodic 
  Beam. 
  505 
  

  

  complicated 
  by 
  the 
  fact 
  that 
  the 
  residual 
  gas 
  is 
  decomposed 
  

   into 
  free 
  ions, 
  as 
  is 
  demonstrated 
  by 
  J. 
  J. 
  Thomson. 
  

  

  2. 
  Every 
  point 
  on 
  a 
  body 
  exposed 
  to 
  cathode-rays 
  becomes 
  

   a 
  point 
  of 
  emanation 
  for 
  .arrays 
  which 
  go 
  in 
  all 
  directions, 
  

   both 
  in 
  the 
  tube 
  and 
  in 
  the 
  body 
  exposed, 
  to 
  a 
  considerable 
  

   depth, 
  so 
  that 
  they 
  can 
  pass 
  through 
  it 
  and 
  emerge. 
  If 
  we 
  

   maintain, 
  then, 
  that 
  the 
  <r-rays 
  already 
  exist 
  in 
  the 
  impinging 
  

   beam, 
  we 
  must 
  admit 
  that 
  when 
  they 
  meet 
  a 
  body 
  they 
  do 
  

   not 
  go 
  straight, 
  but 
  are 
  diffused 
  in 
  all 
  directions. 
  

  

  3. 
  Photographic 
  impressions 
  external 
  to 
  the 
  tube 
  and 
  the 
  

   shadows 
  shown 
  by 
  fluorescent 
  screens 
  move 
  or 
  are 
  modified 
  

   in 
  accordance 
  with 
  the 
  deviations 
  of 
  the 
  internal 
  cathode- 
  

   rays 
  ; 
  hence 
  we 
  are 
  forced 
  to 
  admit 
  that 
  the 
  points 
  struck 
  by 
  

   the 
  deflected 
  rays 
  have 
  also 
  become 
  points 
  of 
  emanation 
  for 
  

   non-deflectible 
  <r-rays 
  ; 
  and 
  it 
  would 
  be 
  absurd 
  to 
  suppose 
  

   that 
  these 
  latter 
  already 
  existed 
  in 
  the 
  beam 
  which 
  excited 
  

   them. 
  

  

  4. 
  As 
  a 
  last 
  defence 
  of 
  the 
  proposition, 
  then, 
  one 
  would 
  

   have 
  to 
  maintain 
  that, 
  if 
  not 
  all, 
  a 
  great 
  part 
  at 
  any 
  rate 
  of 
  

   the 
  #-rays 
  were 
  contained 
  in 
  the 
  cathodic 
  beam 
  — 
  that 
  part 
  

   which 
  does 
  not 
  obey 
  magnetic 
  action. 
  

  

  Later 
  on 
  I 
  shall 
  describe 
  some 
  experiments 
  which 
  show, 
  on 
  

   the 
  contrary, 
  that 
  if 
  at 
  any 
  rate 
  rays 
  incapable 
  of 
  deflexion 
  

   may 
  enter 
  into 
  the 
  formation 
  of 
  the 
  cathode-beam, 
  such 
  rays 
  

   have 
  a 
  degree 
  of 
  intensity 
  incomparably 
  less 
  than 
  the 
  #-rays 
  

   that 
  issue 
  from 
  the 
  same 
  tube. 
  

  

  5. 
  There 
  remains, 
  therefore, 
  no 
  other 
  explanation 
  than 
  this 
  : 
  

   that 
  the 
  cathode-rays 
  are 
  transformed 
  when 
  they 
  strike 
  an 
  

   obstacle 
  ; 
  just 
  as 
  occurs 
  in 
  the 
  common 
  phenomena 
  of 
  calo- 
  

   rescence 
  and 
  fluorescence 
  produced 
  by 
  the 
  various 
  rays 
  of 
  the 
  

   solar 
  spectrum. 
  

  

  6. 
  On 
  the 
  other 
  hand, 
  the 
  cathode-rays 
  properly 
  so-called 
  

   — 
  those 
  that 
  can 
  be 
  deflected 
  by 
  magnetic 
  action 
  — 
  are 
  reflected 
  

   and 
  are 
  transmitted 
  through 
  thin 
  strata, 
  passing 
  into 
  a 
  vacuum 
  

   or 
  into 
  the 
  air 
  with 
  all 
  their 
  characteristic 
  properties. 
  This 
  

   was 
  taught 
  by 
  Lenard 
  and 
  confirmed 
  by 
  recent 
  experiments 
  

   of 
  photographs 
  taken 
  within 
  the 
  tubes. 
  These 
  photographs, 
  

   if 
  the 
  wrapper 
  containing 
  the 
  sensitive 
  film 
  is 
  very 
  thin, 
  are 
  

   at 
  bottom 
  nothing 
  but 
  the 
  repetition 
  under 
  another 
  form 
  of 
  

   those 
  (now 
  become 
  classic) 
  obtained 
  by 
  Lenard 
  himself. 
  

  

  7 
  . 
  It 
  is 
  natural 
  that 
  no 
  regularity 
  should 
  have 
  been 
  observed 
  

   in 
  the 
  reflexion 
  of 
  the 
  cathode-rays 
  : 
  in 
  the 
  first 
  place, 
  the 
  

   surfaces 
  employed 
  have 
  not, 
  as 
  a 
  rule, 
  been 
  smooth 
  and 
  po- 
  

   lished 
  enough 
  ; 
  in 
  the 
  second 
  place, 
  mirrors 
  optically 
  perfect 
  

   may 
  prove 
  furrowed 
  for 
  these 
  rays. 
  Nor 
  do 
  I 
  understand 
  

   how 
  any 
  one 
  can 
  affirm 
  that 
  they 
  do 
  not 
  follow 
  the 
  laws 
  of 
  

  

  