566  Pharmaceutical  Still  and  Vapor  Condenser.  {Kxn'ioy\Strm' 
inner  surface  of  the  cone,  k,  and  by  its  slant  will  run  into  the  gulley,  e, 
which  is  in  turn  placed  slanting  into  the  cone  to  allow  the  flowing  off 
of  the  condensed  liquid  through  the  tube  h.  The  water-joint,  d,  may 
be  filled  with  water,  but  better,  according  to  the  solvent  to  be  recovered, 
with  oil  or  glycerin,  and  it  makes  the  closure  absolute  and  air-tight, 
without  either  the  danger  of  escaping  vapor  and  loss,  or  of  explosion. 
The  hood  can  easily  be  lifted  to  inspect  the  contents  of  the  dish, 
or  to  replenish  the  same  if  necessary,  doing  away  with  the  screws, 
flanges,  and  packing  usually  employed.  To  admit  of  proper  operation 
of  the  water-joint,  however,  care  must  be  had  to  make  the  escape-pipe, 
h,  of  the  proper  diameter,  and  give  it  sufficient  dip  to  cause  the  con- 
densed liquid  to  flow  off  readily,  for  with  a  small  tube,  as  I  had  at  first, 
and  horizontally  placed,  I  soon  found  that  the  filling  of  the  pipe  with 
liquid  and  the  condensing  of  the  vapor  in  the  hood  caused  a  vacuum 
which  rapidly  sucked  up  the  liquid  from  the  water-joint.  Care  must 
also  be  observed  that  the  apparatus  should  be  perfectly  level ;  the 
liquid  in  the  water-joint  will  give  the  best  indication  for  that  purpose. 
An  apparatus  such  as  I  have  exhibited  will  answer  all  the  purposes 
pointed  out,  both  as  an  evaporator  and  a  still.  The  heat  necessary  for 
its  operation  may  be  had  either  from  a  gas  stove,  or,  where  gas  is  not 
at  hand,  and  even  with  greater  economy,  by  a  coal-oil  stove,  or  may 
readily  be  operated  by  placing  it  on  the  top  of  an  ordinary  kitchen 
range  or  stove.  There  is  absolutely  no  danger  from  explosion,  and  the 
recovered  liquid,  if  highly  inflammable,  may  be  led  away  by  a  proper 
tube  from  any  dangerous  proximity  of  the  flames.  The  fact  that  the 
evaporating  dish  is  made  of  copper  will  not  interfere  with  the  evapo- 
ration of  acid  liquids,  as  these  can  be  placed  in  porcelain  dishes  inside 
of  it  without  interfering  with  the  results. 
The  advantages  of  this  apparatus  are  its  simplicity  and  small  expense, 
the  rapidity  with  which  evaporation  is  effected  by  it,  its  adaptability  to 
any  scale,  the  fact  that  in  it  evaporation  may  be  conducted  to  the  very 
end,  and  the  ease  with  which  residua  may  be  removed  and  the 
apparatus  itself  be  cleaned.  Its  work  as  a  still  is  fully  equal  and 
greater  than  an  ordinary  one  of  its  size,  while  it  is  perhaps  the  only 
apparatus  by  which  vapor  can  be  condensed  at  a  comparatively  low  tem- 
perature and  without  boiling  of  the  contents.  For  the  manufacture  of 
the  fluid  and  solid  extracts,  oleoresins,  abstracts,  etc.,  on  a  small  scale,  I 
certainly  know  of  no  more  suitable  apparatus  and  one  more  adapted 
to  the  wants  of  the  pharmacist.    It  might  still  further  be  improved 
