﻿596 
  Hornor 
  — 
  Use 
  of 
  Sealing 
  Wax 
  as 
  a 
  Source 
  of 
  

  

  After 
  two 
  hours 
  the 
  heating 
  current 
  became 
  fairly 
  steady 
  and 
  

   a 
  smooth 
  curve, 
  from 
  A 
  to 
  B, 
  was 
  obtained. 
  The 
  cathode 
  was 
  

   allowed 
  to 
  stand 
  cold 
  with 
  the 
  vacuum 
  up 
  for 
  two 
  days. 
  On 
  

   heating 
  to 
  the 
  same 
  temperature 
  and 
  starting 
  the 
  discharge 
  

   again 
  the 
  current 
  rose 
  to 
  a 
  maximum 
  value 
  in 
  an 
  hour 
  and 
  then 
  

   remained 
  comparatively 
  steady 
  for 
  the 
  rest 
  of 
  the 
  run. 
  The 
  

   steady 
  current 
  value 
  shown 
  in 
  curve 
  2, 
  fig. 
  2, 
  was 
  very 
  little 
  

   smaller 
  than 
  the 
  maximum, 
  which 
  in 
  tarn 
  was 
  much 
  smaller 
  

   than 
  the 
  steady 
  value 
  for 
  the 
  preceding 
  run. 
  After 
  five 
  days 
  

   another 
  run 
  was 
  made 
  with 
  the 
  same 
  platinum 
  strip 
  and 
  lime 
  

   heated 
  to 
  the 
  same 
  temperature. 
  This 
  run 
  gave 
  a 
  maximum 
  

   less 
  than 
  the 
  steady 
  value 
  for 
  the 
  second 
  run, 
  as 
  shown 
  by 
  

   curve 
  3. 
  It 
  has 
  the 
  same 
  general 
  characteristics 
  as 
  curve 
  2. 
  

   The 
  discharge 
  voltage 
  for 
  these 
  curves 
  was 
  approximately 
  400 
  

   volts, 
  the 
  heating 
  current 
  4'63 
  amperes, 
  and 
  the 
  pressure 
  varied 
  

   from 
  -005 
  to 
  '01§ 
  m 
  ™ 
  Hg. 
  In 
  the 
  last 
  two 
  curves 
  the 
  heating 
  

   current 
  was 
  steady. 
  The 
  curves 
  in 
  fig. 
  2 
  indicate 
  that 
  the 
  

   activity 
  of 
  the 
  red 
  wax 
  decays 
  with 
  time. 
  This 
  is 
  also 
  shown 
  

   in 
  a 
  striking 
  manner 
  by 
  curves 
  1, 
  2, 
  and 
  3, 
  fig. 
  3. 
  The 
  maxi- 
  

   mum 
  value 
  of 
  the 
  current 
  during 
  any 
  given 
  run, 
  after 
  the 
  lime 
  

   had 
  been 
  cold 
  from 
  1 
  to 
  4 
  days, 
  was 
  always 
  less 
  than 
  the 
  steady 
  

   value 
  of 
  the 
  current 
  for 
  the 
  preceding 
  run. 
  Apparently 
  when 
  

   the 
  lime 
  is 
  allowed 
  to 
  become 
  cold 
  it 
  is 
  not 
  able 
  to 
  regain 
  the 
  

   activity 
  it 
  had 
  at 
  the 
  end 
  of 
  the 
  previous 
  run. 
  However, 
  the 
  

   activity 
  that 
  it 
  does 
  acquire 
  it 
  regains 
  quickly. 
  

  

  The 
  relation 
  between 
  the 
  maxima 
  and 
  the 
  number 
  of 
  hours 
  

   between 
  them 
  is 
  shown 
  by 
  fig. 
  4. 
  Evidently 
  these 
  maxima 
  

   decrease 
  very 
  rapidly 
  at 
  first. 
  

  

  When 
  the 
  lime 
  is 
  used 
  for 
  the 
  first 
  time 
  it 
  is 
  very 
  difficult 
  to 
  

   adjust 
  the 
  heating 
  current 
  to 
  a 
  value 
  that 
  will 
  give 
  smooth 
  curves 
  

   similar 
  to 
  2 
  and 
  3 
  in 
  fig. 
  2. 
  The 
  form 
  of 
  the 
  curve 
  is 
  more 
  

   likely 
  to 
  be 
  that 
  shown 
  in 
  curve 
  1, 
  fig. 
  3. 
  In 
  this 
  the 
  number 
  

   of 
  electrons 
  emitted 
  for 
  the 
  first 
  two 
  and 
  one-half 
  hours 
  in- 
  

   creased 
  very 
  slowly, 
  when 
  suddenly 
  it 
  rose 
  to 
  a 
  very 
  high 
  max- 
  

   imum 
  and 
  then 
  almost 
  as 
  suddenly 
  fell 
  to 
  a 
  much 
  lower 
  steady 
  

   value. 
  The 
  temperature 
  was 
  that 
  corresponding 
  to 
  cherry-red. 
  

   This 
  sudden 
  and 
  very 
  high 
  maximum 
  indicates 
  that 
  most 
  of 
  

   the 
  electrons 
  which 
  may 
  possibly 
  be 
  emitted 
  under 
  these 
  con- 
  

   ditions 
  acquired 
  sufficient 
  energy 
  to 
  escape 
  almost 
  simultane- 
  

   ously 
  and 
  thus 
  caused, 
  as 
  it 
  were, 
  an 
  explosion. 
  Curves 
  2 
  and 
  

   3, 
  in 
  fig. 
  3, 
  again 
  show 
  the 
  same 
  characteristics 
  as 
  curves 
  2 
  

   and 
  3 
  in 
  fig. 
  2. 
  After 
  the 
  lime 
  has 
  once 
  been 
  heated, 
  the 
  sub- 
  

   sequent 
  currents 
  start 
  much 
  more 
  easily 
  and 
  rise 
  to 
  a 
  maximum 
  

   more 
  quickly, 
  suggesting 
  that 
  the 
  electrons 
  are 
  in 
  a 
  state 
  more 
  

   favorable 
  to 
  emission. 
  The 
  beam 
  was 
  visible 
  to 
  the 
  eye 
  in 
  

   curves 
  1, 
  2, 
  and 
  3, 
  fig. 
  3, 
  from 
  A, 
  B, 
  and 
  C 
  on. 
  

  

  If 
  the 
  discharge 
  voltage 
  was 
  cut 
  off 
  while 
  the 
  heating 
  con- 
  

  

  