﻿Physics. 
  219 
  

  

  method 
  of 
  correcting 
  the 
  irregularity 
  by 
  adjusting 
  the 
  amount 
  of 
  

   acid 
  present 
  is 
  simply 
  a 
  device 
  for 
  replacing 
  the 
  copper 
  by 
  

   cuprous 
  oxide 
  ; 
  and 
  although 
  its 
  results 
  are 
  not 
  very 
  erroneous, 
  

   it 
  must 
  be 
  considered 
  scientifically 
  unsound. 
  

  

  We 
  found 
  that, 
  by 
  reducing 
  very 
  much 
  the 
  temperature 
  and 
  

   by 
  protecting 
  the 
  solution 
  from 
  the 
  air 
  so 
  as 
  to 
  exclude 
  this 
  

   oxidizing 
  environment, 
  it 
  was 
  possible 
  to 
  obtain 
  maximum 
  and 
  

   minimum 
  results, 
  from 
  acidified 
  cuprous 
  and 
  cupric 
  solutions 
  

   respectively, 
  which 
  were 
  fairly 
  close 
  together. 
  The 
  average 
  

   between 
  these 
  two 
  was 
  still 
  much 
  less 
  than 
  the 
  amount 
  corre- 
  

   sponding 
  to 
  the 
  silver 
  voltameter. 
  The 
  obvious 
  inference 
  from 
  

   this 
  discrepancy 
  was 
  that 
  the 
  silver 
  voltameter 
  is 
  itself 
  erroneous, 
  

   and 
  deposits, 
  for 
  some 
  reason 
  or 
  other, 
  too 
  much 
  silver 
  to 
  corre- 
  

   spond 
  to 
  the 
  current. 
  

  

  The 
  careful 
  investigation 
  of 
  the 
  sources 
  of 
  this 
  inaccuracy, 
  

   both 
  from 
  the 
  study 
  of 
  earlier 
  work 
  and 
  from 
  our 
  own 
  experi- 
  

   ence, 
  led 
  us 
  to 
  conclude 
  that 
  the 
  irregularities 
  were 
  caused 
  by 
  

   some 
  unusual 
  action 
  at 
  the 
  anode, 
  and 
  hence 
  it 
  is 
  obvious 
  that 
  by 
  

   excluding 
  this 
  anode 
  with 
  the 
  help 
  of 
  a 
  fine-grained 
  porous 
  cup 
  

   it 
  was 
  possible 
  also 
  to 
  exclude 
  the 
  irregularities. 
  Upon 
  careful 
  

   trial 
  the 
  porous 
  cup 
  was 
  found 
  to 
  give 
  desirably 
  constant 
  results, 
  

   which 
  were 
  0.082 
  per 
  cent 
  lower 
  than 
  the 
  amounts 
  of 
  silver 
  

   obtained 
  with 
  the 
  same 
  current 
  from 
  Lord 
  Rayleigh's 
  standard. 
  

   This 
  amount, 
  as 
  is 
  indicated 
  below, 
  was 
  just 
  enough 
  to 
  account 
  for 
  

   the 
  discrepancy 
  noticed 
  in 
  the 
  work 
  upon 
  copper. 
  It 
  was 
  found 
  

   in 
  the 
  same 
  way, 
  that 
  Patterson 
  and 
  Guthe's 
  method 
  yielded 
  a 
  

   result 
  about 
  0.2 
  per 
  cent 
  higher 
  than 
  the 
  porous 
  cup 
  voltameter. 
  

   Upon 
  applying 
  these 
  corrections 
  to 
  the 
  chief 
  results 
  which 
  have 
  

   been 
  obtained 
  for 
  the 
  electrochemical 
  equivalents 
  of 
  silver, 
  it 
  was 
  

   found 
  that 
  all 
  of 
  the 
  results 
  were 
  fairly 
  concordant, 
  indicating 
  a 
  

   deposit 
  of 
  about 
  1.1172 
  milligrams 
  of 
  silver 
  per 
  ampere 
  per 
  

   second. 
  

  

  Since 
  the 
  electrochemical 
  equivalent 
  of 
  copper 
  upon 
  the 
  same 
  

   basis 
  was 
  found 
  to 
  be 
  equal 
  to 
  about 
  0.3292 
  milligram 
  per 
  ampere 
  

   per 
  second, 
  and 
  since 
  the 
  atomic 
  weights 
  of 
  silver 
  and 
  copper 
  and 
  

   silver 
  are 
  respectively 
  107.93 
  and 
  63.604, 
  it 
  is 
  clear 
  that 
  Fara- 
  

   day's 
  Law 
  is 
  verified 
  more 
  precisely 
  than 
  before. 
  For 
  1.1172: 
  

   0.3292 
  = 
  2(107.93): 
  63.60. 
  

  

  Conversely, 
  supposing 
  Faraday's 
  Law 
  to 
  hold 
  rigidly, 
  and 
  the 
  

   value 
  63.60 
  to 
  represent 
  the 
  atomic 
  weight 
  of 
  copper, 
  the 
  agree- 
  

   ment 
  furnishes 
  evidence 
  of 
  the 
  accuracy 
  of 
  the 
  new 
  method. 
  

  

  3. 
  Irreversible 
  Radiation 
  Phenomena. 
  — 
  An 
  important 
  theoreti- 
  

   cal 
  article 
  on 
  this 
  subject 
  has 
  been 
  published 
  by 
  Professor 
  Max 
  

   Planck. 
  It 
  is 
  a 
  study 
  of 
  the 
  application 
  of 
  the 
  electromagnetic 
  

   theory 
  of 
  light 
  to 
  the 
  laws 
  of 
  thermodynamics. 
  The 
  author 
  recog- 
  

   nizes 
  the 
  fact 
  that 
  since 
  the 
  phenomena 
  of 
  heat 
  satisfy 
  the 
  second 
  

   law 
  of 
  thermodynamics, 
  the 
  electromagnetic 
  theory 
  must 
  also 
  

   embrace 
  this 
  law 
  in 
  its 
  generality. 
  He 
  discusses 
  the 
  phenomena 
  

   of 
  heat 
  and 
  light 
  from 
  the 
  point 
  of 
  view 
  of 
  this 
  theory; 
  regarding 
  

   the 
  molecules 
  as 
  oscillating 
  systems, 
  sending 
  out 
  or 
  receiving 
  

   electrical 
  waves, 
  and 
  he 
  finds 
  the 
  necessity 
  of 
  enunciating 
  electro- 
  

  

  