ON  CHLOROFORM. 
293 
off  directly  into  a  drain  connecting  with  the  sewer.  A  system 
of  upright  steam  pipes  was  attached  near  the  centre  of  the  bot- 
tom, and  so  arranged  that  the  steam  ascended  the  inner  (smallest), 
and  descended  through  the  outer  (larger)  pipes.  About  half-way 
up  on  the  side  a  three-quarter-inch  steam  pipe  passed  into  the 
interior,  and  was  bent  in  an  oblique  direction  towards  the 
bottom,  its  lower  half  being  perforated  for  the  purpose  of  inject- 
ing steam. 
The  top  contained  a  man-hole  16  inches  in  diameter,  with  a 
high  flange  cast  around  it,  upon  which  fitted  a  copper  still-head  ; 
into  the  tubulure,  3  inches  in  diameter,  a  pipe  of  pure  lead  was 
inserted,  reaching  below  the  base  of  the  head ;  the  opening  was 
closed  by  a  screw-cap.  The  head  was  connected  with  an  iron 
safety  chamber,  the  object  of  which  was  to  prevent  the  mixture 
in  the  still  from  reaching  the  receiver,  in  case  it  should  boil  over. 
The  charge  was  mixed  in  the  third  story,  in  an  iron  kettle, 
then  strained  into  a  lead-lined  wooden  tank  elevated  on  the 
second  floor,  and  from  this,  by  means  of  a  two-inch  round  way 
cock,  and  a  piece  of  lead  or  rubber  tube,  through  the  tubulure, 
which  was  nearly  even  with  the  floor,  run  into  the  still  below. 
As  much  as  800  pounds  of  chlorinated  lime,  containing  30 
per  cent,  active  chlorine,  has  been  worked  successfully  at  one 
time  ;  this  was  mixed  with  350  gallons  of  water  and  18  gallons 
of  95  per  cent,  alcohol,  and  the  mixture  heated  to  120u  F.  by 
blowing  steam  into  it.  The  temperature  was  ascertained  by  a 
thermometer  dipping  into  solution  of  chloride  of  zinc,  which  was 
kept  in  an  iron  tube  inserted  in  the  lower  half  of  the  still.  A 
little  steam  was  now  kept  in  the  upright  pipes, — merely  sufficient  • 
to  compensate  for  the  loss  of  heat  by  the  surrounding  air.  Soon 
the  temperature  rises,  and  the  chloroform  distils  over  ;  when  it 
ceases  to  distil,  steam  is  again  blown  in,  and  the  mixture  kept  in 
active  boiling  for  some  time,  until  all  chloroform  and  alcohol  has 
distilled. 
The  crude  chloroform  settled  in  the  receiver  from  the  distillate 
was  transferred  to  the  wash-can,  where  it  was  agitated  with  three 
successive  portions  of  water.  When  the  alcohol  had  been  thus 
removed,  the  chloroform  was  agitated  in  a  leaden  tank  with 
about  one-sixth  of  its  weight  of  sulphuric  acid,  and  the  two 
