NEW  APPARATUS  FOR  RECTIFYING  SPIRITS. 
7 
water  in  the  tub,  is  hermetically  sealed  at  the  bottom,  and  re- 
ceived into  a  flanch  there,  and  by  this  flanch  bolted  to  the  centre 
of  the  bottom  of  the  tub.  The  upper  end  of  this  piece  of  pipe 
is  fitted  with  an  ordinary  steam  fitter's  reducing  socket,  and  by 
this  adapted  to  receive  a  short  piece  of  J  inch  iron  pipe  in  con- 
tinuation. This  piece  of  \  inch  pipe  is  bored  out  true  and 
screwed  in  perfectly  tight.  This  small  pipe  is  fitted  with  a  piston 
having  a  long  bearing  for  packing,  and  the  piston  and  rod  have 
a  narrow  passage  way  drilled  throughout  their  entire  length. 
The  upper  end  of  this  channel  is  perfectly  secured  by  a  soft  iron 
screw  plug.  A  fine  screw  thread  is  cut  upon  the  outside  of  the 
upper  end  of  this  piston  rod,  and  over  this  passes  a  female  por- 
tion with  an  internal  thread,  furnished  at  some  portion  with  a 
milled  head  for  facility  of  turning.  This  arrangement  enables 
the  operator  to  lengthen  the  piston  rod  at  pleasure,  in  adapting 
the  contrivance  to  different  degrees  of  temperature,  or  in  adjust- 
ing it  nicely  to  any  desired  degree.  The  rounded  upper  end  of 
this  female  portion  bears  upon  a  lever  arranged  upon  a  stout  bar 
of  wood  across  the  top  of  the  tub,  and  weighted  as  shown  in  the 
figure.  The  weight  upon  the  lever  is  so  adjusted  as  to  close  a 
valve  against  the  head  of  water  in  the  cold  water  pipes  which 
supply  the  tub,  but  pressure  on  the  lever  from  the  piston  rod 
head  raises  the  weight,  and  allows  the  head  of  water  to  raise 
the  valve  so  that  the  tub  may  be  supplied.  The  iron  tubes  are 
filled  with  mercury,  the  packed  piston  put  in  place,  and  the 
channel  in  its  centre  filled  with  mercury  to  the  careful  ex- 
clusion of  air,  and  the  little  plug  screwed  tightly  into  its  place, 
so  as  to  hermetically  seal  the  carefully  filled  mercury  column. 
The  apparatus  being  thus  arranged,  as  the  water  in  the  tub  be- 
comes heated  the  mercury  expands,  and  the  expansion  is  multi- 
plied in  the  small  pipe  where  it  pushes  up  the  piston.  The 
milled  head  of  the  female  part  is  turned  so  as  to  shorten  the 
piston  as  the  expansion  takes  place,  till  the  water  rises  to  the 
desired  degree  of  temperature.  Then  the  farther  expansion  is 
allowed  to  act  upon  the  lever  and  raise  the  closing  weight  of  the 
valve,  which  it  does  just  in  proportion  to  the  amount  of  the  ex- 
pansion from  the  temperature  of  the  water.  The  principal 
difficulty  in  the  practical  application  of  this  simple  contrivance. 
