﻿596 
  Messrs. 
  Cameron 
  and 
  Oettino-er 
  on 
  Electromotive 
  

  

  Time. 
  

  

  A. 
  

  

  B. 
  

  

  Temp. 
  

  

  E.M.F. 
  

  

  E.M.F./B. 
  

  

  Mean. 
  

  

  A.M. 
  

  

  

  

  C. 
  

  

  volt. 
  

  

  

  

  11.15 
  

  

  335-7 
  

  

  172-8 
  

  

  31-9 
  

  

  0-311 
  

  

  1-799x10-3 
  

  

  

  18 
  

  

  339-6 
  

  

  174-9 
  

  

  31-9 
  

  

  0-316 
  

  

  1-805 
  

  

  

  24 
  

  

  341-7 
  

  

  176-0 
  

  

  31-6 
  

  

  0-318 
  

  

  1-808 
  

  

  1-804x10-3 
  

  

  35 
  

  

  338-4 
  

  

  174-3 
  

  

  30-1 
  

  

  0324 
  

  

  1-858 
  

  

  

  38 
  

  

  348-7 
  

  

  179-5 
  

  

  30-1 
  

  

  0-338 
  

  

  1-882 
  

  

  

  40 
  

  

  348-2 
  

  

  179-3 
  

  

  29-8 
  

  

  0-334 
  

  

  1-865 
  

  

  

  45 
  

  

  341-7 
  

  

  176-0 
  

  

  29-7 
  

  

  0-318 
  

  

  1-806 
  

  

  

  49 
  

  

  335-2 
  

  

  172-6 
  

  

  29-6 
  

  

  0-c07 
  

  

  1-780 
  

  

  1-838 
  

  

  P.M. 
  

  

  3.45 
  

  

  347-6 
  

  

  1790 
  

  

  21-5 
  

  

  0-339 
  

  

  1-895 
  

  

  

  49 
  

  

  380-7 
  

  

  196-0 
  

  

  21-4 
  

  

  0-361 
  

  

  1-840 
  

  

  

  51 
  

  

  337-3 
  

  

  173-7 
  

  

  21-4 
  

  

  0-319 
  

  

  1-836 
  

  

  1-857 
  

  

  The 
  change 
  observed 
  is 
  onlj 
  3 
  per 
  cent., 
  i. 
  e. 
  is 
  within 
  the 
  

   limit 
  of 
  experimental 
  error 
  previously 
  found. 
  Experiments 
  

   were 
  also 
  made 
  to 
  ascertain 
  the 
  change 
  of 
  temperature 
  

   caused 
  by 
  friction 
  while 
  the 
  liquid 
  was 
  passing 
  through 
  the 
  

   capillary. 
  A 
  thermometer 
  was 
  introduced 
  into 
  the 
  tube 
  

   connecting 
  the 
  bottle 
  with 
  the 
  capillary, 
  and 
  a 
  second 
  placed 
  

   in 
  the 
  stream 
  of 
  liquid 
  issuing. 
  A 
  rise 
  of 
  temperature 
  was 
  

   observed 
  which 
  never 
  exceeded 
  1°*5. 
  For 
  experiments 
  at 
  

   ordinary 
  temperatures, 
  therefore, 
  slight 
  temperature 
  changes 
  

   need 
  not 
  be 
  considered. 
  

  

  Experiments 
  with 
  Dilute 
  Solutions. 
  

  

  The 
  question 
  under 
  discussion 
  in 
  this 
  paper 
  would 
  be 
  tested 
  

   most 
  advantageously 
  if 
  series 
  of 
  measurements 
  could 
  be 
  made 
  

   with 
  different 
  concentrations 
  for 
  different 
  acids 
  and 
  alkalies. 
  

   We 
  attempted 
  to 
  make 
  such 
  measurements, 
  but 
  found 
  many 
  

   difficulties 
  in 
  the 
  attempt 
  to 
  employ 
  a 
  large 
  range 
  of 
  concen- 
  

   tration. 
  When 
  the 
  concentration 
  is 
  greater 
  than 
  N/1000 
  the 
  

   E.M.F. 
  obtained 
  with 
  the 
  pressures 
  employed 
  becomes 
  less 
  than 
  

   0*1 
  volt. 
  In 
  this 
  case 
  there 
  become 
  of 
  great 
  importance 
  the 
  

   errors 
  which 
  arise 
  from 
  a 
  difference 
  of 
  potential 
  of 
  both 
  elec- 
  

   trodes 
  when 
  the 
  tube 
  is 
  filled 
  with 
  liquid 
  at 
  rest. 
  We 
  never 
  

   succeeded 
  in 
  avoiding 
  casual 
  differences 
  between 
  the 
  two 
  elec- 
  

   trodes, 
  in 
  this 
  condition, 
  of 
  the 
  order 
  of 
  several 
  millivolts. 
  In 
  

   determining 
  these 
  values 
  before 
  and 
  after 
  the 
  determination 
  of 
  

   the 
  E.M.F. 
  produced 
  by 
  flow 
  of 
  liquid, 
  we 
  found 
  that 
  often 
  

   they 
  change 
  both 
  in 
  value 
  and 
  in 
  sign. 
  Devices 
  such 
  as 
  

   connecting 
  the 
  electrodes 
  before 
  the 
  measurement, 
  insulating 
  

   as 
  well 
  as 
  possible 
  the 
  glass 
  surface 
  (both 
  tube 
  and 
  flask) 
  &c., 
  

   proved 
  insufficient 
  remedies. 
  It 
  was 
  therefore 
  necessary 
  

  

  