420 
PREPARATION  OF  ALUMINIUM,  SODIUM,  ETC. 
The  apparatus  used  for  the  preparation  of  sodium  is  repre- 
sented by  fig.  2.  The  fireplace,  CC,  of  the  furnace,  shown  in 
action,  is  lined  with  firebricks ;  the  bars,  G,  are  moveable,  and 
ihe  flue  should  be  furnished  with  a  well  fitting  damper.  In  the 
breast  of  the  furnace  there  is  a  square  opening,  P,  closed  by  a 
plate  of  cast  iron,  with  a  hole  through  which  the  tube,  T,  may 
project. 
A  mercury  bottle,  furnished  with  an  iron  tube  about  three 
inches  long,  serves  as  the  distillate  or  vessel.  It  is  supported 
upon  two  firebricks,  K,  about  four  inches  high,  and  hollowed  at 
the  top  so  as  to  fit  the  side  of  the  bottle. 
Fig.  3. 
The  receiver  (fig.  3)  in  which  the 
sodium  is  condensed  is  made  of  two  pieces 
of  sheet  iron  about  one  tenth  of  an  inch 
thick,  AA.  One  of  these  pieces  is  flat, 
except  at  the  end,  C,  where  it  is  ham- 
mered so  as  to  form  a  semi-cylindrical 
hollow.  The  other  piece  is  turned  up 
at  the  sides  so  that,  when  fitted  to  the 
plate,  A,  there  is  a  space  of  about  one 
fifth  of  an  inch  wide  and  a  hollow,  corresponding  to  that  in  the 
other  plate,  is  hammered  at  the  end,  so  that  together  they  will 
form  a  collar  to  receive  the  conical  end  of  the  tube  T.  The 
edges  are  filed,  so  as  to  fit  close,  and  are  kept  in  their  place  by 
two  binding  screws  (W,  fig.  2.) 
When  the  bottle  containing  the  mixture  is  placed  in  the  fur- 
nace, and  the  fire  made  up,  a  copious  evolution  of  gas  commences; 
and,  after  about  half  an  hour,  a  white  vapor  of  carbonate  of  soda 
is  deposited,  which  would  seem  to  indicate  that  the  gas  contained 
sodium.  However,  the  receiver  must  not  be  attached  to  the 
bottle  until  a  cold  iron  rod  passed  into  the  tube,  T>  is  found  to  be 
covered  with  sodium.  When  the  draught  of  the  furnace  is  good, 
the  sodium  is  disengaged  rapidly,  and  the  receiver  becomes  so 
hot  that  the  condensed  metal  flows  out  of  the  open  extremity,  D, 
where  it  is  reeeived  in  an  iron  basin,  L,  containing  c<*al  tar 
naphtha.  If,  after  a  time,  the  receiver  should  become  stopped  up, 
it  is  replaced  by  another,  previously  heated  to  about  400?  or 
500°  F. 
