MANUFACTURE,  IMPURITIES  AND  TESTS  OF  CHLOROFORM.  433 
acetic  acids,  acetic  ether,  aldehyde,  chloride  of  ethyl,  chloral, 
&c.  The  remainder  of  the  process,  and  that  in  which  almost 
all  the  imperfections  lie,  has  for  its  object  the  separation  and 
condensation  of  the  chloroform,  and  the  utilization  of  the  resi- 
dues. The  mixed  vapors  are  passed  together  into  a  leaden  vessel 
arranged  as  a  Wolf's  bottle,  and  there  made  to  bubble  through 
milk  of  lime  kept  at  a  temperature  of  about  205°.  Here  the 
watery  vapor,  chlorine,  hydrochloric  acid,  and  some  of  the  chloric 
nated  compounds,  are  for  the  most  part  condensed  or  combined, 
while  the  more  volatile  substances,  among  which  are  the  chloro- 
form and  alcohol,  pass  on  to  the  first  condenser  or  cooler.  The 
water  around  the  worm  of  this  cooler  is  kept  nicely  regulated  at 
about  165°,  so  that  in  it  much  of  the  vapor  of  water  yet  remain- 
ing, and  almost  all  the  alcohol  vapor,  is  condensed  and  abstracted, 
leaving  the  vapor  of  chloroform  to  pass  on  to  the  final  conden- 
sers in  a  state  tolerably  pure.  These  final  condensers  are  supplied 
with  cold  water,  and  in  them  the  remaining  condensable  vapors 
are  brought  to  the  liquid  condition.  The  product  of  crude 
chloroform  at  this  stage  is  about  thirty-six  fluid  ounces. 
During  this  part  of  the  process  the  contents  of  the  still  oc- 
casionally froth  up,  and  would  pass  over  with  the  vapors  except 
for  the  arrangement  of  a  cribriform  cup  of  lead  at  the  top  of 
the  still,  inside,  whereby  a  fine  shower  of  cold  water  from  a  hose 
faucet  is  made  to  fall  upon  the  frothing  mixture. 
Steam  is  then  admitted  to  the  still  again,  and  the  distillation 
continued,  after  the  impure  chloroform  has  ceased  to  separate, 
until  the  distillate  no  longer  contains  any  traces  of  alcohol  or 
chloroform.  This  weak  distillate  is  used  instead  of  water,  to 
dilute  the  succeeding  charge. 
The  crude  chloroform  is  then  washed  three  times  with  an  equal 
volume  of  cold  water,  to  deprive  it  of  alcohol,  acetic  acid,  &c, 
and  set  aside  till  the  product  of  several  charges  is  accumulated. 
It  is  then  shaken  with  an  equal  volume  of  a  dilute  solution  of 
carbonate  of  soda  to  free  it  from  traces  of  chlorine,  and  at  the 
end  of  the  process,  is  finished  by  rectification  from  a  mixture  of 
slaked  and  quick  lime,  in  a  glass  apparatus.  The  washings, 
except  those  of  carbonate  of  soda,  with  the  liquid  condensed  in 
the  cooler,  and,  every  third  charge  the  contents  of  the  lime 
purifier,  are  added  to  the  succeeding  charge,  and  in  this  way 
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