﻿104 
  Messrs. 
  A. 
  Holt 
  and 
  E. 
  Hopkinson 
  on 
  iJecomposition 
  

  

  the 
  circuit, 
  but 
  care 
  was 
  taken 
  that 
  the 
  amount 
  of 
  electricity 
  

   passing 
  during 
  each 
  ten 
  minutes 
  of 
  sparking 
  was 
  approximately 
  

   the 
  same. 
  

  

  Without 
  altering 
  the 
  apparatus 
  in 
  any 
  way 
  or 
  admitting 
  

   air 
  to 
  it, 
  a 
  series 
  of 
  pairs 
  of 
  experiments 
  were 
  made 
  in 
  the 
  

   manner 
  just 
  described. 
  

  

  The 
  reason 
  for 
  doing 
  this, 
  and 
  not 
  cleaning 
  off 
  the 
  metal 
  

   deposited 
  on 
  the 
  glass 
  of 
  the 
  spark-tube 
  during 
  each 
  of 
  these 
  

   experiments, 
  was 
  to 
  see 
  to 
  what 
  extent 
  the 
  metallic 
  film, 
  

   apart 
  from 
  the 
  actual 
  spray, 
  exercised 
  a 
  catalytic 
  influence. 
  

   During 
  each 
  ten 
  minutes'' 
  sparking 
  the 
  film 
  would 
  become 
  

   thicker 
  and 
  denser, 
  while 
  the 
  amount 
  of 
  spray 
  round 
  tbe 
  

   cathode 
  would 
  remain 
  fairly 
  constant, 
  since 
  it 
  only 
  depends 
  

   on 
  the 
  spark 
  and 
  the 
  consequent 
  heating 
  of 
  the 
  electrode. 
  

   If, 
  then, 
  the 
  ratio 
  of 
  the 
  amount 
  of 
  electrolytic 
  gas 
  collected 
  

   when 
  the 
  cathode 
  was 
  at 
  C 
  to 
  that 
  when 
  it 
  was 
  at 
  D 
  was 
  found 
  

   to 
  alter 
  through 
  successive 
  pairs 
  of 
  experiments, 
  it 
  would 
  show 
  

   that 
  the 
  metallic 
  film 
  exercised 
  a 
  catalytic 
  influence 
  apart 
  

   from 
  that 
  of 
  the 
  spray 
  round 
  the 
  heated 
  cathode. 
  

  

  The 
  following 
  table 
  gives 
  the 
  results 
  of 
  some 
  of 
  these 
  

   experiments. 
  

  

  

  

  

  Vol. 
  of 
  

  

  Vol. 
  of 
  

  

  

  No. 
  of 
  

  

  

  Diameter 
  of 
  

   bulbs 
  round 
  

  

  electrolytic 
  

  

  electrolytic 
  

  

  

  pairs 
  of 
  

  

  Electrodes. 
  

  

  gas 
  collected 
  

  

  gas 
  collected 
  

  

  Eatio 
  

  

  experi- 
  

  

  

  electrodes. 
  

  

  in 
  10 
  mins. 
  

  

  in 
  10 
  mins. 
  

  

  B/A. 
  

  

  ments. 
  

  

  

  wben 
  cathode 
  

  

  wben 
  cathode 
  

  

  

  

  

  

  was 
  at 
  C. 
  

  

  was 
  at 
  D. 
  

  

  

  

  

  

  A. 
  

  

  B. 
  

  

  

  1. 
  

  

  Platinum 
  

  

  1 
  cm. 
  

  

  8-58 
  c.c. 
  

  

  208 
  c.c. 
  

  

  0-242 
  

  

  2. 
  

  

  wire 
  - 
  5 
  mm. 
  

   diameter. 
  

  

  

  809 
  c.c. 
  

  

  1-62 
  c.c. 
  

  

  0-201 
  

  

  3. 
  

  

  

  

  8-96 
  c.c. 
  

  

  1 
  -02 
  c.c. 
  

  

  0181 
  

  

  4. 
  

  

  Aluminium 
  

  

  1 
  cm. 
  

  

  244 
  c.c. 
  

  

  249 
  c.c. 
  

  

  1018 
  

  

  5. 
  

  

  wire 
  05 
  mm. 
  

   diameter. 
  

  

  

  5*96 
  c.c. 
  

  

  614 
  c.c. 
  

  

  1031 
  

  

  0. 
  

  

  

  

  7 
  17 
  c.c. 
  

   2*68 
  c.o. 
  

  

  7 
  •.")() 
  c.c. 
  

   ITS 
  c.c. 
  

  

  1-047 
  

  

  7. 
  

  

  Platinum 
  

  

  1 
  cm. 
  

  

  0-690 
  

  

  

  wire 
  1 
  mm. 
  

  

  

  

  

  

  8. 
  

  

  diameter. 
  

  

  

  L 
  '99 
  0.0. 
  

  

  1 
  32 
  c.c 
  

  

  0-063 
  

  

  0. 
  

  

  Platinum 
  

  

  wire 
  ()•.") 
  niiii. 
  

  

  5 
  cms. 
  

  

  3-18 
  c.c. 
  

  

  2*94 
  cc. 
  

  

  0-924 
  

  

  10. 
  

  

  diameter. 
  

  

  

  3*14 
  c.c. 
  

  

  2*87 
  c.c. 
  

  

  0-914 
  

  

  