﻿FEB. 
  4, 
  1922 
  VINAL 
  AND 
  ALTRUP 
  : 
  CELLS 
  AT 
  LOW 
  TEMPERATURES 
  

  

  69 
  

  

  the 
  heat 
  of 
  the 
  reaction 
  for 
  an 
  electrolyte 
  of 
  1.280 
  specific 
  gravity 
  is 
  

   87800 
  4- 
  4420 
  = 
  92220 
  calories. 
  

  

  The 
  value 
  for 
  K 
  at 
  25° 
  C. 
  and 
  electrolyte 
  of 
  specific 
  gravity 
  1.280 
  

   was 
  2.120 
  volts. 
  The 
  temperature, 
  25° 
  C, 
  corresponds 
  to 
  298° 
  abso- 
  

   lute. 
  Substituting 
  these 
  values 
  for 
  T, 
  E 
  and 
  Q 
  in 
  equation 
  (2) 
  the 
  

   value 
  for 
  the 
  temperature 
  coefficient 
  dE/dT 
  is 
  found 
  to 
  be 
  0.0004.07 
  

   The 
  results 
  of 
  the 
  experiment 
  showed 
  a 
  decrease 
  in 
  the 
  open 
  circuit 
  

   voltage 
  of 
  0.0386 
  volt 
  when 
  the 
  temperature 
  was 
  decreased 
  97° 
  from 
  

   which 
  dE/dT 
  = 
  0.000398. 
  

  

  Open 
  O/rcuj/ 
  \/b//t^tBS 
  of/^^^ 
  Cg// 
  

   onc/S/or^c^e 
  Ce/J 
  a/JLow 
  '^rBjO'sr-cf/iir^s 
  _ 
  

  

  an 
  G/ec^oin€;Mn 
  

  

  Ce//s 
  /n 
  cr 
  cfoiziJc 
  CLKi/h</a/rjcic/r&/. 
  

  

  ' 
  J.ZVS 
  ^ 
  

  

  ce// 
  J.ZVS 
  

  

  Oc/yv, 
  J3itf 
  

  

  

  

  _J 
  I 
  I 
  L 
  

  

  -J 
  I 
  I 
  L_ 
  

  

  TeTT^cer^c/ijr'e^, 
  c^ar&e^ 
  O 
  

  

  Fig. 
  2. 
  Open 
  circuit 
  voltages 
  of 
  dry 
  cell 
  and 
  storage 
  cell 
  of 
  low 
  temperatures. 
  

  

  The 
  agreement 
  of 
  this 
  observed 
  value 
  with 
  that 
  calculated 
  from 
  

   thermochemical 
  data 
  is 
  better 
  than 
  would 
  be 
  expected 
  and 
  gives 
  a 
  

   striking 
  proof 
  of 
  the 
  validity 
  of 
  the 
  Gibbs-Helmholtz 
  equation 
  over 
  

   a 
  wide 
  range 
  of 
  temperature. 
  

  

  A 
  second 
  series 
  of 
  measurements 
  extending 
  the 
  temperature 
  range 
  

   down 
  to 
  —170° 
  C. 
  was 
  then 
  made. 
  Only 
  the 
  electrometer 
  readings 
  

   are 
  of 
  value 
  at 
  this 
  low 
  temperature. 
  The 
  results 
  on 
  a 
  dry 
  cell 
  and 
  a 
  

   storage 
  cell 
  are 
  shown 
  graphically 
  in 
  Fig. 
  2. 
  These 
  are 
  the 
  open 
  

   circuit 
  voltages 
  measured 
  electrostatically. 
  The 
  storage 
  cell 
  showed 
  

  

  