370  M.  G.  Quincke  on  Electrolysis,  and  the 
of  free  electricity  e,  and  each  molecule  of  chlorine  the  quantity 
of  free  electricity  ef. 
This  free  electricity  arises  from  the  different  degrees  of  attrac- 
tion which  sodium,  chlorine,  hydrogen,  and  oxygen,  being  simul- 
taneously in  mutual  proximity  in  space,  exert  upon  the  two 
electric  fluids.  As  in  the  case  of  the  excitation  of  free  electri- 
city by  the  contact  of  different  metals,  so  in  this  case  also  the 
free  electricity  of  each  constituent  may  depend  upon  the  tem- 
perature of  the  bodies  in  contact,  and  may  alter  with  the  con- 
dition of  the  solvent.  The  magnitude  and  signs  of  the  masses  of 
electricity  e  and  er  remain  to  be  determined,  but  may  in  general 
be  either  both  equal  or  different. 
Each  of  the  two  masses  of  electricity  will  be  moved  with  a  force 
dV         ,<       dY  , 
€  and 5— 
dx  doc 
where  the  force  is  positive  in  the  direction  of  the  positive  elec- 
tricity, and  V  is  the  potential  of  free  electricity  for  the  corre- 
sponding section  of  the  conductor.  Within  the  same  section  of 
the  linear  conductor  the  potential  V  is  constant,  and,  in  electro- 
lytes as  well  as  in  metals,  depends  only  on  the  free  electricity  on 
the  surface  of  the  conductor  (compare  §  57  etseqq.).  Within  the 
conductor  there  is,  indeed,  free  electricity  on  the  various  consti- 
tuent molecules ;  but  at  the  same  place  in  space  equal  and  oppo- 
site quantities  of  electricity  lie  so  near  each  other  that  they  exer 
equal  and  opposite  actions,  and  thus  their  action  on  more  distant 
particles  of  electricity  is  nullified.  If  a  constant  current  of  elec- 
tricity traverses  the  conductor,  it  is  quite  immaterial  for  the 
present  considerations  whether  the  free  electricity  has  collected 
on  the  external  surface  in  consequence  of  a  mechanical  displace- 
ment of  liquid  particles,  or  from  some  other  cause. 
Since  the  quantities  of  electricity  on  the  individual  molecules 
can  only  move  slowly  or  with  difficulty  from  one  molecule  to  an- 
other, the  quantities  of  electricity  e  and  e'  will  carry  with  them 
the  constituent-molecules  (ions)  to  which  they  adhere;  and, 
owing  to  friction  against  the  surrounding  liquid,  each  will  very 
soon  acquire  a  constant  mean  velocity. 
These  constant  velocities 
^-Cjeandt/s-O^     .     .     .     (1) 
will  have  the  direction  of  the  forces  acting  upon  the  electrical 
masses  e  and  e',  and  with  these  masses  will  change  their  sign — 
that  is,  their  direction.  The  constant  C  which  defines  the  velo- 
city of  such  a  material  constituent-molecule  and  the  adhering 
quantity  of  electricity  e,  besides  depending  on  the  magnitude  of 
