﻿Ions 
  from 
  Hot 
  Salts. 
  471 
  

  

  Immediately 
  after 
  the 
  salt 
  was 
  first 
  heated 
  measurements 
  

   of 
  e/m 
  were 
  made 
  by 
  the 
  balance 
  method. 
  Four 
  consistent 
  

   measurements 
  gave 
  m/H 
  = 
  97. 
  This 
  value 
  is 
  difficult 
  to 
  

   interpret, 
  and 
  I 
  am 
  inclined 
  to 
  think 
  that 
  the 
  electrons 
  

   present 
  were 
  vitiating 
  the 
  measurements. 
  

  

  Calcium 
  Bromide. 
  CaBr 
  

  

  The 
  emission 
  from 
  this 
  substance 
  did 
  not 
  seem 
  either 
  so 
  

   copious 
  or 
  so 
  persistent 
  as 
  that 
  from 
  the 
  iodides 
  of 
  the 
  

   alkaline 
  earth 
  metals 
  and 
  from 
  calcium 
  fluoride, 
  but 
  it 
  lasted 
  

   long 
  enough 
  to 
  make 
  a 
  number 
  of 
  experiments 
  with 
  it. 
  An 
  

   experiment 
  with 
  fresh 
  salt 
  at 
  465° 
  Pt. 
  gave 
  an 
  emission 
  of 
  

   about 
  3xl0 
  _n 
  amp., 
  which 
  varied 
  very 
  little 
  for 
  about 
  

   15 
  minutes 
  and 
  then 
  fell 
  away 
  quite 
  rapidly. 
  Practically 
  

   none 
  of 
  this 
  emission 
  was 
  stopped 
  by 
  the 
  magnetic 
  field, 
  so 
  

   that 
  it 
  apparently 
  consisted 
  entirely 
  of 
  heavy 
  ions. 
  

  

  Measurements 
  of 
  e/m 
  were 
  made 
  on 
  another 
  freshly 
  heated 
  

   specimen 
  using 
  the 
  balance 
  method. 
  Different 
  negative 
  

   potentials 
  were 
  applied 
  in 
  order 
  to 
  check 
  the 
  consistency 
  of 
  

   the 
  results. 
  Previous 
  work 
  on 
  the 
  other 
  salts 
  had 
  shown 
  

   that 
  when 
  the 
  method 
  for 
  determining 
  e/m 
  for 
  the 
  heavy 
  

   negative 
  ions 
  was 
  not 
  working 
  satisfactorily 
  (owing 
  to 
  the 
  

   cause 
  which 
  has 
  been 
  tentatively 
  attributed 
  to 
  an 
  effect 
  

   arising 
  from 
  the 
  negative 
  electrons) 
  the 
  values 
  obtained 
  

   when 
  different 
  potentials 
  were 
  used 
  did 
  not 
  agree 
  with 
  one 
  

   another. 
  The 
  numbers 
  obtained 
  in 
  the 
  present 
  case 
  are 
  

   shown 
  in 
  the 
  following; 
  table 
  : 
  — 
  

  

  Negative 
  Potential 
  (volts)... 
  214 
  128 
  84 
  42 
  

  

  2x 
  (1 
  = 
  -0625 
  cm.) 
  4'65 
  5"97 
  7"35 
  10*85 
  

  

  e/m 
  108 
  107 
  106 
  116 
  

  

  mfH. 
  89 
  90 
  91 
  82 
  

  

  Temperature 
  (° 
  Pt.) 
  526 
  526 
  526 
  526 
  

  

  These 
  values 
  of 
  m/H 
  are 
  sufficiently 
  consistent 
  and 
  the 
  

   mean 
  88 
  is 
  near 
  enough 
  to 
  80, 
  the 
  chemical 
  equivalent 
  

   weight 
  of 
  Br, 
  to 
  indicate 
  definitely 
  that 
  the 
  ions 
  from 
  this 
  

   substance 
  are 
  most 
  probably 
  atoms 
  of 
  bromine 
  which 
  are 
  

   combined 
  with 
  an 
  electron. 
  

  

  It 
  is 
  perhaps 
  worthy 
  of 
  remark 
  that 
  the 
  deviations 
  of 
  the 
  

   observed 
  values 
  of 
  m/H 
  from 
  the 
  calculated 
  values 
  for 
  the 
  

   ions 
  to 
  which 
  they 
  have 
  been 
  attributed 
  are 
  in 
  every 
  case, 
  for 
  

   the 
  heavy 
  negative 
  ions 
  examined, 
  in 
  such 
  a 
  direction 
  as 
  would 
  

   occur 
  if 
  the 
  ions 
  in 
  question 
  were 
  mixed 
  with 
  another 
  kind 
  for 
  

  

  