﻿94 
  Messrs. 
  A. 
  Holt 
  and 
  E. 
  Hopkinson 
  on 
  Decomposition 
  

  

  This 
  separation 
  was 
  well 
  shown 
  by 
  the 
  following 
  experi- 
  

   ment 
  : 
  — 
  A 
  stream 
  o£ 
  water-vapour 
  at 
  about 
  15 
  mm. 
  pressure 
  

   was 
  drawn 
  into 
  the 
  tube 
  B 
  (fig. 
  1), 
  where 
  it 
  divided, 
  one 
  

  

  Fkr.l. 
  

  

  / 
  \ 
  

  

  iA 
  

  

  ^~ 
  

  

  B 
  

  

  / 
  — 
  V 
  

  

  

  

  > 
  D 
  

  

  

  W4TC--R 
  ~V_ 
  

  

  To 
  ConDEns 
  ERi 
  

  

  \IA?OuH 
  

  

  

  

  AND 
  ~P*nV 
  

  

  half 
  passing 
  straight 
  on 
  to 
  a 
  condenser 
  D 
  and 
  pump, 
  while 
  

   the 
  other 
  half 
  passed 
  through 
  the 
  spark 
  between 
  A 
  and 
  C, 
  

   and 
  on 
  to 
  a 
  second 
  condenser, 
  E, 
  and 
  pump. 
  Both 
  con- 
  

   densers 
  were 
  kept 
  at 
  the 
  same 
  temperature, 
  and 
  both 
  pumps 
  

   were 
  worked 
  at 
  approximately 
  similar 
  rates. 
  Under 
  these 
  

   conditions 
  it 
  was 
  found 
  that 
  the 
  hydrogen 
  produced 
  by 
  the 
  

   spark 
  diffused 
  into 
  the 
  stream 
  of 
  vapour 
  passing 
  from 
  B 
  to 
  D, 
  

   where 
  it 
  appeared 
  in 
  excess, 
  while 
  a 
  proportionate 
  excess 
  of 
  

   oxygen 
  was 
  collected 
  from 
  E, 
  since 
  this 
  gas 
  could 
  not 
  readilv 
  

   diffuse 
  back 
  against 
  the 
  water-vapour 
  current 
  passing 
  from 
  

   BtoE. 
  

  

  No. 
  of 
  

   experiment. 
  

  

  Vol. 
  of 
  excess 
  

   of 
  hydrogen 
  col- 
  

   lected 
  from 
  I). 
  

  

  Vol. 
  of 
  excess 
  

   of 
  oxygen 
  col- 
  

   lected 
  from 
  I-]. 
  

  

  Total 
  vol. 
  of 
  electro- 
  

   lytic 
  gas 
  collected 
  

  

  from 
  D 
  + 
  E. 
  

  

  1 
  

  

  . 
  2-14 
  c.c. 
  

   1-94 
  c.c. 
  

   220 
  c.c. 
  

  

  104 
  c.c. 
  

   0-94 
  cc. 
  

   107 
  cc. 
  

  

  11-2 
  cc. 
  

  

  io;> 
  c.c. 
  

  

  10-0 
  c.c. 
  

  

  •\ 
  

  

  Ii 
  seemed 
  possible 
  that 
  the 
  separation 
  of 
  the 
  oxygen 
  and 
  

   hydrogen 
  in 
  the 
  spark 
  might 
  really 
  be 
  a 
  diffusion-pheno- 
  

   menon, 
  for 
  most 
  of 
  the 
  results 
  obtained 
  by 
  Perrol 
  and 
  by 
  

   Chapman 
  and 
  Lidbury 
  can 
  be 
  explained 
  by 
  this 
  hypothesis. 
  

  

  When 
  electric 
  sparks 
  pass 
  through 
  water-vapour 
  contained 
  

   in 
  an 
  apparatus 
  like 
  that 
  used 
  by 
  Chapman 
  and 
  Lidbury, 
  a 
  

   mixture 
  of 
  oxygen 
  and 
  hydrogen 
  i> 
  produced 
  in 
  the 
  path 
  of 
  

  

  