'^Spimber^^92'3:}    Methyl  Alcokol  and  Ethyl  Alcohol.  635 
and  each  of  the  others  less  than  the  preceding  one,  which  is  the  reason 
for  the  varying  heights  of  the  connections. 
Tar  Still. — ^The  tar  in  the  bottom  of  the  wooden  settlers  is  drawn 
off  and  collected  and  then  refined  in  a  wooden  tar  still  equipped 
with  a  copper  steam  heating  coil  and  with  a  copper  tubular  con- 
denser. The  wood  oils  are  recovered  by  means  of  this  still.  The 
tar  residue  left  in  the  still  is  conveyed  to  the  tar  storage  tank  to  be 
used  as  'fuel. 
Primary  Still. — The  liquor  in  the  last  of  the  wooden  settlers, 
which  is  practically  free  from  tar  in  suspension,  is  run  by  gravity 
through  a  copper  pipe  into  a  copper  primary  still,  and  the  feed  is 
continuous  and  kept  so  by  a  float  valve.  In  this  still  the  tar  in 
solution  is  separated.  The  still  is  made  entirely  of  copper  and  sup- 
plied with  a  copper  ■  steam  heating  coil,  copper  neck  and  copper 
tubular  condenser.  The  tar  from  the  primary  still  is  considered 
a  waste  product  and  is  conveyed  to  the  tar  storage  tank  to  be  used 
as  fuel. 
Neutralizing. — The  liquor  which  is  obtained  by  the  condensa- 
tion of  the  vapor  issuing  from  the  primary  still  and  passing  through 
the  condenser  is  conveyed  to  a  wooden  neutralizing  tub,  where  it 
is  treated  with  slaked  lime.  The  tub  is  provided  with  an  agitator 
to  properly  carry  on  the  neutralization. 
Lime  Lee  Still. — ^The  neutralized  liquor  is  carried  to  a  steel 
still,  called  a  lime  lee  still,  and  here  the  acetate  of  lime  is  separated 
from  the  wood  alcohol.  It  is  equipped  with  a  copper  steam  heating 
coil  and  with  a  copper  tubular  condenser.  From  the  lime  lee  still 
the  process  separates  into  two  branches. 
Settling  Tanks  and  Steam  Pans. — We  will  first  follow  the  progress 
of  the  acetate  solution,  which  is  what  remains  in  the  Hme  lee  still 
after  the  wood  alcohol  has  been  driven  off  in  the  form  of  vapor. 
The  acetate  solution  is  pumped  or  blown  with  steam  or  compressed 
air  from  the  still  into  steel  settling  tanks,  in  which  the  solid  matter 
precipitates.  The  solution  is  then  drawn  off  and  piped  into  steam- 
jacketted  evaporating  pans,  where  the  greater  portion  of  the  water 
is  evaporated,  leaving  a  substance  of  consistency  which  can  be 
handled  with  an  ordinary  hand  shovel.  From  these  pans  the  sub- 
stance, which  is  acetate  of  lime,  is  shoveled  out  onto  drying  floors 
situated  above  the  ovens,  and  it  is  spread  in  a  thin  layer  and  allowed 
to  become  thoroughly  dry.    This  is  now  grey  acetate  of  lime  of  an 
