﻿136 
  

  

  Mr. 
  John 
  S. 
  Townsend 
  on 
  Electrical 
  

  

  more 
  than 
  five 
  minutes 
  at 
  a 
  time, 
  when 
  a 
  number 
  of 
  experi- 
  

   ments 
  have 
  to 
  be 
  performed 
  requiring 
  the 
  same 
  electrification 
  

   in 
  each 
  case. 
  

  

  The 
  gases 
  were 
  first 
  bubbled 
  through 
  potassium 
  iodide 
  and 
  

   then 
  through 
  strong 
  sulphuric 
  acid, 
  so 
  that 
  they 
  should 
  enter 
  

   the 
  tube 
  D 
  perfectly 
  dry. 
  The 
  cylinder 
  and 
  tubing 
  con- 
  

   nected 
  with 
  it 
  were 
  thoroughly 
  dried 
  by 
  heating 
  them 
  with 
  

   a 
  Bunsen-burner 
  and 
  then 
  blowing 
  dry 
  air 
  through 
  them. 
  

   This 
  precaution 
  is 
  absolutely 
  necessary 
  as 
  it 
  only 
  requires 
  

   a 
  very 
  slight 
  amount 
  of 
  moisture 
  to 
  form 
  a 
  cloud, 
  and 
  this 
  

   would 
  impede 
  the 
  motion 
  of 
  the 
  carriers. 
  

  

  12. 
  A 
  series 
  of 
  experiments 
  of 
  the 
  following 
  type 
  were 
  

   then 
  performed. 
  The 
  cylinder 
  was 
  connected 
  to 
  a 
  pair 
  of 
  

   quadrants 
  of 
  the 
  electrometer, 
  which 
  were 
  kept 
  to 
  earth 
  while 
  

   the 
  cylinder 
  was 
  being 
  filled 
  and 
  insulated 
  before 
  blowing 
  

   out 
  the 
  gas, 
  so 
  as 
  to 
  get 
  the 
  readings 
  on 
  the 
  same 
  part 
  of 
  the 
  

   scale. 
  The 
  tube 
  A 
  was 
  closed, 
  and 
  D 
  connected 
  to 
  the 
  

   delivery-tube 
  of 
  the 
  sulphuric-acid 
  wash-bottle, 
  and 
  a 
  current 
  

   of 
  fourteen 
  amperes 
  sent 
  through 
  the 
  cell. 
  It 
  only 
  required 
  

   the 
  current 
  to 
  run 
  for 
  about 
  five 
  minutes 
  to 
  completely 
  fill 
  C 
  

   with 
  the 
  charged 
  gas. 
  The 
  circuit 
  was 
  then 
  broken 
  and 
  the 
  

   tube 
  B 
  closed. 
  At 
  the 
  same 
  time 
  a 
  stop-watch 
  was 
  started. 
  

   After 
  the 
  lapse 
  of 
  t 
  minutes 
  the 
  ends 
  A 
  and 
  B 
  are 
  opened, 
  

   and 
  dry 
  unelectrified 
  air 
  blown 
  through 
  C 
  to 
  expel 
  the 
  

   charged 
  gas. 
  This 
  caused 
  the 
  spot 
  of 
  light 
  on 
  the 
  electro- 
  

   meter-scale 
  to 
  move 
  n 
  divisions, 
  which 
  is 
  proportional 
  to 
  p 
  

   the 
  density 
  of 
  the 
  electrification 
  after 
  the 
  gas 
  has 
  remained 
  

   in 
  the 
  cylinder 
  for 
  a 
  time 
  t. 
  

  

  The 
  numbers 
  thus 
  obtained 
  for 
  n 
  and 
  t 
  are 
  given 
  in 
  

   Tables 
  IV. 
  and 
  V., 
  the 
  first 
  being 
  for 
  charged 
  hydrogen 
  and 
  

   the 
  second 
  for 
  charged 
  oxygen. 
  

  

  Table 
  IV. 
  

  

  Table 
  V. 
  

  

  n. 
  

  

  t. 
  

  

  

  n. 
  

  

  t. 
  

  

  32 
  

  

  

  

  

  49 
  

  

  

  

  25-5 
  

  

  1 
  

  

  

  375 
  

  

  2 
  

  

  20-5 
  

  

  2 
  

  

  

  29-5 
  

  

  4 
  

  

  17-5 
  

  

  3 
  

  

  

  24-5 
  

  

  6 
  

  

  15-5 
  

   14 
  

  

  4 
  

   5 
  

  

  

  22 
  

  

  8 
  

  

  

  

  

  