16  ON  THE  STEATIFICATIONS  AND  DAEK  BAND  IN  ELECTEICAL  DISCHAEGES. 
the  magnet  into  two  sets  of  stratifications,  each  set  having  a tendency  to  rotate  round 
the  pole  of  the  magnet  in  opposite  directions : the  character  of  the  electrical  discharge 
with  relation  to  these  two  forms  can  always  be  determined  by  a magnet. 
57.  I have  in  all  instances  found  that  the  discharge  from  the  positive  terminal  exhibits 
a dominant  action,  as  if  the  force  issued  from  this  direction.  I have  akeady  alluded  to 
the  remarkable  length  (36.)  of  the  column  of  stratifications,  and  I have  given  a drawing, 
Plate  I.  fig.  8,  which  I consider  exhibits  a direction  of  force  from  the  positive  to  the 
negative,  centring  to  the  axis  of  stratification ; in  the  following  arrangement  this  domi- 
nant character  of  the  positive  discharge  is  further  developed. 
58.  Plate  I.  fig.  12  represents  a bent  glass  tube,  about  one  inch  internal  diameter, 
in  which  both  wires  can  be  covered  with  liquid  mercury ; the  wires  « to  5 are  31  inches 
apart,  from  a io  c the  distance  is  24  inches,  from  h to  d ^ inches,  from  (Z  to  c 3 inches ; by 
inclining  the  apparatus,  the  mercury  from  a can  be  elongated  towards  c to  the  length  of 
8 or  10  inches ; in  this  condition,  if  a is  negative,  the  entire  surface  of  the  mercuiy  is 
covered  with  a brilliant  white  glow ; if  it  is  positive,  the  meremy  is  entirely  luminous 
at  the  extreme  end  nearest  c,  but  the  remainder  is  unafiected  by  the  discharge. 
59.  I cannot  conclude  this  Note  vdthout  expressing  the  deep  sense  of  the  obhgation 
which  I owe  to  Dr.  Faeaday,  who  has,  during  the  course  of  these  investigations,  not  only 
afforded  me  the  advantage  of  many  important  suggestions,  but  has  also  spared  me  much 
of  his  valuable  time.  I am  at  present  continuing  these  most  interesting  experiments  on 
the  stratification,  and  should  the  results  obtained  be  such  as  I anticipate,  they  will  form 
the  subject  of  a further  communication. 
March  2,  1858. 
J.  P.  G. 
