﻿Chemistry 
  and 
  Physics. 
  379 
  

  

  We 
  know 
  that 
  for 
  a 
  same 
  quotient 
  of 
  mass 
  by 
  the 
  charge, 
  the 
  

   product 
  of 
  the 
  field 
  by 
  the 
  radius 
  of 
  curvature 
  is 
  proportional 
  to 
  

   the 
  speed.* 
  Thus 
  the 
  particles 
  which 
  strike 
  the 
  plate 
  the 
  farthest 
  

   from 
  the 
  source 
  will 
  be 
  those 
  possessing 
  the 
  greatest 
  speed, 
  and 
  

   it 
  is 
  natural 
  that 
  they 
  should 
  also 
  be 
  the 
  most 
  penetrating. 
  

  

  This 
  is 
  a 
  simple 
  idea 
  from 
  which 
  a 
  presumption 
  may 
  result, 
  but 
  

   not 
  a 
  certainty. 
  In 
  fact 
  other 
  hypotheses 
  could 
  explain 
  the 
  

   same 
  coincidence 
  which 
  can 
  only 
  be 
  considered 
  as 
  an 
  accessory 
  

   proof. 
  But 
  the 
  experiment 
  of 
  M. 
  Curie 
  gives 
  us 
  a 
  proof 
  of 
  

   another 
  order. 
  He 
  has 
  placed 
  beyond 
  doubt 
  the 
  fact 
  that 
  the 
  

   emission 
  of 
  radium 
  charges 
  bodies 
  which 
  receive 
  it 
  negatively 
  \ 
  

   while 
  the 
  radium 
  itself 
  is 
  charged 
  positively. 
  

  

  This 
  fact 
  is 
  of 
  such 
  importance, 
  it 
  throws 
  such 
  sudden 
  light 
  on 
  

   the 
  whole 
  question, 
  that 
  the 
  eminent 
  physicists 
  to 
  whom 
  we 
  owe 
  

   these 
  marvelous 
  discoveries 
  would 
  naturally 
  wish 
  to 
  put 
  it 
  in 
  

   evidence, 
  and 
  we 
  believe 
  they 
  would 
  have 
  succeeded 
  sooner 
  had 
  

   it 
  not 
  been 
  for 
  the 
  extraordinary 
  difficulties 
  offered 
  by 
  the 
  experi- 
  

   ment. 
  We 
  do 
  not 
  propose 
  to 
  give 
  it 
  in 
  detail, 
  or 
  to 
  diminish 
  the 
  

   interest 
  of 
  the 
  publication 
  in 
  extenso 
  which 
  belongs 
  to 
  M. 
  and 
  

   Mdme. 
  Curie. 
  We 
  will 
  only 
  say 
  that 
  the 
  extreme 
  minuteness 
  of 
  

   the 
  effects 
  to 
  be 
  measured 
  necessitated 
  the 
  most 
  delicate 
  appara- 
  

   tus, 
  and 
  that 
  the 
  method 
  with 
  piezo-electric 
  quartz, 
  of 
  which 
  M. 
  

   and 
  Mdme. 
  Curie 
  have 
  made 
  such 
  constant 
  and 
  skilful 
  use, 
  alone 
  

   could 
  lead 
  to 
  positive 
  results. 
  But 
  this 
  is 
  not 
  all. 
  The 
  already 
  

   known 
  action 
  of 
  the 
  new 
  radiations 
  was 
  the 
  principal 
  obstacle 
  to 
  

   the 
  success 
  of 
  the 
  experiment. 
  Radium 
  placed 
  at 
  the 
  mouth 
  of 
  

   a 
  Faraday 
  cylinder, 
  while 
  sending 
  its 
  own 
  charged 
  particles 
  into 
  

   the 
  interior, 
  created 
  by 
  that 
  action 
  a 
  permanent 
  conductor 
  along 
  

   their 
  path, 
  and 
  provoked 
  the 
  immediate 
  dissipation 
  of 
  the 
  whole 
  

   of 
  the 
  charges 
  carried. 
  It 
  was 
  therefore 
  necessary 
  to 
  abandon 
  

   this 
  simple 
  method, 
  and 
  to 
  have 
  recourse 
  to 
  a 
  series 
  of 
  artifices, 
  

   of 
  which 
  the 
  most 
  important 
  consisted 
  of 
  enclosing 
  the 
  receiver 
  

   in 
  a 
  double 
  envelope, 
  the 
  first 
  or 
  outer 
  one 
  consisting 
  of 
  a 
  metallic 
  

   sheet 
  connected 
  to 
  earth, 
  while 
  the 
  second 
  was 
  isolated. 
  A 
  part 
  

   of 
  this 
  double 
  envelope 
  was 
  formed 
  of 
  thin 
  leaves, 
  permitting 
  

   the 
  radiation 
  to 
  reach 
  the 
  receiver. 
  

  

  In 
  a 
  second 
  experiment, 
  the 
  radium 
  itself 
  was 
  enclosed 
  in 
  the 
  

   double 
  envelope 
  and 
  discharged 
  its 
  negative 
  charge 
  to 
  the 
  exte- 
  

   rior 
  without 
  compensation. 
  

  

  Only 
  one 
  interpretation 
  seems 
  still 
  possible, 
  at 
  least 
  for 
  a 
  por- 
  

   tion 
  of 
  the 
  emission 
  of 
  radium 
  ; 
  this 
  emission 
  is 
  composed 
  of 
  ma- 
  

   terial 
  particles 
  carrying 
  negative 
  charges. 
  

  

  We 
  might, 
  at 
  first 
  sight, 
  ask 
  if 
  the 
  non-deviable 
  rays 
  are 
  not 
  a 
  

   particular 
  form 
  of 
  deviable 
  rays. 
  This 
  does 
  not 
  seem 
  to 
  be 
  the 
  

   case, 
  for 
  the 
  absorption 
  they 
  undergo 
  would 
  rather 
  send 
  them 
  

   beyond 
  the 
  most 
  deviable 
  rays 
  which 
  have 
  been 
  met 
  with. 
  They 
  

   are 
  either 
  of 
  another 
  kind, 
  or 
  they 
  have 
  been 
  deprived 
  of 
  their 
  

   charge 
  of 
  electricity. 
  This 
  latter 
  idea 
  is 
  still 
  admissible, 
  and 
  the 
  

  

  m 
  

  

  * 
  _X 
  = 
  Ef), 
  an 
  equation 
  established 
  to 
  explain 
  the 
  curvature 
  of 
  cathodic 
  rays. 
  

  

  