﻿598 
  Messrs. 
  Cameron 
  and 
  Oettinger 
  on 
  Electromotive 
  

  

  Thus 
  for 
  16°, 
  7; 
  = 
  1-111; 
  17°, 
  t? 
  = 
  1-086 
  ; 
  18°, 
  1-059; 
  

   19°, 
  1-033, 
  &c. 
  

  

  In 
  every 
  experiment 
  the 
  potential 
  at 
  zero 
  pressure 
  (i. 
  e. 
  with 
  

   the 
  capillary 
  filled 
  with 
  solution 
  at 
  rest) 
  was 
  first 
  measured, 
  

   until 
  constant, 
  then 
  that 
  at 
  one 
  or 
  more 
  pressures, 
  and 
  finally 
  

   that 
  at 
  zero 
  pressure 
  again. 
  

  

  In 
  these 
  experiments 
  a 
  new 
  tube 
  was 
  used, 
  with 
  the 
  following 
  

   constants: 
  total 
  length, 
  518 
  mm., 
  length 
  between 
  electrodes 
  

   256 
  mm., 
  diameter 
  0-720 
  to 
  0-728 
  mm.* 
  

  

  The 
  following 
  table 
  shows 
  the 
  results 
  with 
  dilute 
  acids. 
  

   A 
  and 
  B 
  have 
  the 
  usual 
  significance. 
  It 
  should 
  be 
  remembered 
  

   that 
  the 
  concentrations 
  are 
  only 
  approximate, 
  and 
  that 
  an 
  

   error 
  of 
  3 
  or 
  4 
  per 
  cent, 
  is 
  possible. 
  Ei 
  and 
  E3 
  are 
  the 
  

   voltages 
  found 
  at 
  zero 
  pressure 
  before 
  and 
  after 
  the 
  actual 
  

   measurement 
  (E2) 
  respectively. 
  E4 
  is 
  the 
  corrected 
  voltage. 
  

   In 
  order 
  to 
  obtain 
  </)^— 
  -(/>„ 
  in 
  volts 
  (Helmholtz's 
  formula 
  is 
  

   given 
  in 
  absolute 
  electrostatic 
  units), 
  the 
  term 
  Eiooo/^t 
  was 
  

   multiplied 
  by 
  the 
  factor 
  rj 
  x 
  0'901 
  x 
  10^, 
  calculated 
  from 
  the 
  

   formula. 
  C 
  is 
  the 
  equivalent 
  of 
  1 
  cm. 
  on 
  the 
  electrometer-scale 
  

   in 
  volts. 
  

  

  Solution. 
  

  

  Concentration. 
  

  

  A. 
  

  

  B. 
  

  

  C. 
  

  

  Temp. 
  

  

  i 
  E.. 
  

  

  E, 
  

  

  HCl 
  

  

  N/5000 
  

  

  372 
  

  

  730 
  

  

  184 
  

   3t51 
  

  

  0-033 
  

  

  16° 
  

  

  -0-016 
  

  

  +0-098 
  

   0-191 
  

  

  

  

  N/5000 
  

  

  389 
  

   740 
  

  

  194 
  

  

  366 
  

  

  0-050 
  

  

  16° 
  

  

  -0-002 
  

  

  +0-105 
  

   0173 
  

  

  CH3COOH... 
  

  

  N/2000 
  

  

  762 
  

  

  384 
  

  

  377 
  

   190 
  

  

  0-033 
  

  

  15° 
  

  

  +0-053 
  

  

  +0-275 
  

   0-168 
  

  

  1 
  

  

  Solution. 
  

  

  E., 
  E, 
  

  

  1//C. 
  

  

  ^looo'^- 
  

  

  <^i-0a. 
  

  

  HCl 
  

  

  ? 
  +0-114+ 
  ? 
  

   0-207+ 
  ? 
  

  

  

  0-1383x105 
  

  

  4-58 
  XlC 
  

   4-24 
  

  

  )-5 
  

  

  4-60+ 
  ? 
  

   4-26+ 
  ? 
  

  

  

  

  

  

  +0-107+2 
  0/0 
  

   0-175+1 
  0/0 
  

  

  

  0-1341x105 
  

  

  4-09x10 
  

   3-52 
  

  

  -5 
  

  

  4-11+2 
  "'0 
  

   3-52+1 
  0/0 
  

  

  CH3OOOH... 
  

  

  +0-052 
  

  

  +0-222+0-4 
  

   0-11 
  5 
  + 
  0-8 
  

  

  /o 
  

   '0 
  

  

  0-1647x105 
  

  

  3-58 
  XlC 
  

   3-70 
  

  

  -5 
  

  

  3-95+0-4 
  0/0 
  

   4-20+0-8 
  0/^ 
  

  

  

  

  

  

  

  

  

  The 
  errors 
  shown 
  after 
  the 
  + 
  sign 
  are 
  calculated 
  on 
  the 
  

   assumption 
  that 
  the 
  flow 
  of 
  liquid 
  produces 
  an 
  E.M.F. 
  equal 
  

  

  * 
  The 
  total 
  length 
  of 
  electrode 
  spaces 
  was 
  16 
  mm. 
  

  

  t 
  E;^QQQ 
  is 
  the 
  voltage 
  calculated 
  for 
  1000 
  mm. 
  pressure. 
  

  

  