﻿470 
  Prof. 
  0. 
  W. 
  Richardson 
  on 
  the 
  

  

  Manganous 
  Chloride. 
  MnCl 
  2 
  . 
  

  

  This 
  substance 
  gave 
  a 
  negative 
  emission 
  at 
  about 
  570° 
  Pt., 
  

   which 
  lasted 
  long 
  enough 
  to 
  enable 
  the 
  following 
  successive 
  

   values 
  of 
  e/m 
  and 
  m/H. 
  for 
  the 
  heavy 
  negative 
  ions 
  to 
  be 
  

   determined 
  by 
  the 
  balance 
  method 
  : 
  — 
  

  

  2x 
  5-4 
  5-8 
  4-9 
  4-8 
  4"8 
  

  

  e/m 
  141 
  163 
  116 
  112 
  112 
  

  

  m/H. 
  68 
  59 
  82 
  88 
  88 
  

  

  I 
  do 
  not 
  feel 
  confident 
  that 
  anything 
  more 
  ought 
  to 
  read 
  

   into 
  the 
  meaning 
  of 
  the 
  above 
  numbers 
  than 
  that 
  they 
  imply 
  

   the 
  presence 
  of 
  heavy 
  negative 
  ions 
  of 
  molecular 
  or 
  atomic 
  

   magnitude, 
  as 
  there 
  was 
  some 
  indication 
  of 
  the 
  presence 
  of 
  

   too 
  many 
  electrons. 
  This 
  salt 
  deserves 
  further 
  investi- 
  

   gation. 
  

  

  Calcium 
  Fluoride. 
  CaF 
  2 
  . 
  

  

  This 
  substance 
  gave 
  a 
  very 
  definite 
  emission 
  which 
  con- 
  

   tained 
  a 
  large 
  percentage 
  of 
  electrons 
  even 
  on 
  first 
  heating. 
  

   The 
  following 
  numbers, 
  obtained 
  after 
  the 
  salt 
  had 
  been 
  

   heated 
  for 
  about 
  2 
  hours 
  at 
  600° 
  C, 
  give 
  an 
  idea 
  of 
  the 
  

   nature 
  of 
  this 
  emission 
  : 
  — 
  

  

  Temperature 
  1 
  46g 
  49g 
  53] 
  569 
  594 
  62g 
  

  

  Total 
  current 
  j 
  g 
  . 
  9 
  1Q 
  _i 
  3 
  2<g 
  1Q 
  _ 
  n 
  j 
  >34 
  10 
  _i 
  3.9 
  x 
  10 
  -10 
  x 
  .33 
  x 
  1Q 
  -9 
  3.55 
  x 
  10 
  - 
  

   (amp.). 
  J 
  

  

  Percentage 
  carried 
  1 
  g 
  . 
  3 
  ^ 
  u 
  2Q 
  . 
  4 
  ^.3 
  13 
  . 
  g 
  

  

  by 
  heavy 
  ions. 
  J 
  

  

  Temperature 
  1 
  656 
  6g7 
  n9 
  75Q 
  ?gl 
  

  

  \ 
  xt.j. 
  J 
  

  

  Total 
  current 
  ] 
  3 
  . 
  7xl0 
  -8 
  i^xlO" 
  7 
  4-6xl0~ 
  7 
  2'1 
  xHT 
  6 
  5-7xl0- 
  6 
  

   (amp.). 
  / 
  

  

  Percentage 
  carried 
  | 
  n 
  .rj 
  g.3 
  g.g 
  4 
  4 
  

  

  by 
  heavy 
  ions. 
  J 
  

  

  About 
  800° 
  the 
  current 
  only 
  increased 
  slowly 
  with 
  the 
  

   temperature. 
  A 
  subsequent 
  test 
  showed 
  that 
  when 
  the 
  

   temperature 
  was 
  raised 
  slowly 
  from 
  781 
  c 
  to 
  1030° 
  Pt., 
  the 
  

   emission 
  only 
  increased 
  by 
  a 
  factor 
  of 
  4. 
  In 
  these 
  experi- 
  

   ments 
  it 
  was 
  noticed 
  that 
  when 
  the 
  magnetic 
  field 
  was 
  turned 
  

   on, 
  the 
  current 
  was 
  small 
  initially 
  and 
  rose 
  in 
  a 
  few 
  minutes 
  

   to 
  a 
  steady 
  value. 
  This 
  behaviour 
  is 
  precisely 
  opposite 
  to 
  

   that 
  observed 
  with 
  calcium 
  iodide 
  when 
  the 
  same 
  change 
  

   had 
  been 
  made. 
  

  

  